Citation
A New Method for the Modeling of Elemental Segregation Behavior and Partitioning in Single Crystal Nickel Base Superalloys

Material Information

Title:
A New Method for the Modeling of Elemental Segregation Behavior and Partitioning in Single Crystal Nickel Base Superalloys
Creator:
CALDWELL, ERIC CHRISTOPHER ( Author, Primary )
Copyright Date:
2008

Subjects

Subjects / Keywords:
Alloying ( jstor )
Alloys ( jstor )
Aluminum ( jstor )
Curvature ( jstor )
Dendrites ( jstor )
Heat resistant alloys ( jstor )
Heat treatment ( jstor )
Solidification ( jstor )
Tantalum ( jstor )
Tungsten ( jstor )

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
Copyright Eric Christopher Caldwell. Permission granted to University of Florida to digitize and display this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Embargo Date:
8/7/2004
Resource Identifier:
56813727 ( OCLC )

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Full Text












A NEW METHOD FOR THE MODELING OF ELEMENTAL SEGREGATION
BEHAVIOR AND PARTITIONING IN SINGLE CRYSTAL NICKEL BASE
SUPERALLOYS















By

ERIC CHRISTOPHER CALDWELL


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA


2004

































Copyright 2004

by

Eric Christopher Caldwell





























This work is dedicated to my family and friends who have been with me through good
times and bad. And for those who travel in harms way, there is a light at the end of the
tunnel. Godspeed!






















"Nothing of value is free"

- from Starship Troopers by Robert A. Heinlein















ACKNOWLEDGMENTS

The author would like to thank and to acknowledge the support of Dr. Gerhard

Fuchs for providing the way and the means, Dr. Reza Abbaschian and Dr. Robert DeHoff

for support and consultation, and my family and friends for their support and

understanding, especially Dr Daniel Villanueva for making me realize that I was in the

wrong career. Additional thanks go to Wayne Acree and the staff of the Major Analytical

Instrument Center (MAIC) at the University of Florida, and oddly enough, the United

States Navy for giving me the backbone, courage and dedication to see the job done.

This material is based on work supported by the National Science Foundation under

Grant No. 0072671.
















TABLE OF CONTENTS

page

A C K N O W L E D G M E N T S ........................................................................ .....................v

LIST OF TABLES ......................................... ............ ..... ix

LIST OF FIGURES ......... ......................... ...... ........ ............ xi

ABSTRACT ........ .............. ............. ...... ...................... xix

CHAPTER

1 INTRODUCTION ............... ................. ........... ................. ... ..... 1

2 LITER A TU RE SEAR CH .................................................. ............................... 9

2.1. Evolution of Nickel Based Superalloys..... .......... ......................................9
2.1.1. The y-y' M atrix ................ .......... ............. ............ ................ .. 10
2.1.2. Casting and Specialized Processing Techniques.................. ............14

3 MATERIALS AND EXPERIMENTAL PROCEDURE ...........................................19

3 .1 M a te ria ls ........................................................................................................ 1 9
3.2. M etallography .................. .. .. ..... ............. ................................ .... .. 21
3.3. Scanning Electron Microscopy/Backscatter Electron Microscopy ...................24
3.3.1. Electron M icroprobe A nalysis........................................ ............... 26
3.3.2. Verification of Applicability of Analysis........ ........... .. ................. 28

4 EXPERIMENTAL RESULTS ............................................................................29

4.1. Prim ary D endrite A rm Spacing ........................................ ....................... 29
4.2. Electron M icroprobe A nalysis.................................... .......................... ......... 30
4.3. Elem ental Segregation and Partitioning ................................... .................32
4.3.1. C obalt P artitioning.......................................................... ............... 38
4.3.2. Chrom ium Partitioning ..................................................... ............. 39
4.3.3. R henium Partitioning........................................... .......................... 43
4.3.4. Tungsten partitioning ........................................................ 46
4.3.5. Tungsten Partitioning with an Addition of Molybdenum ....................47
4.3.6. M olybdenum Partitioning...................................... ........................ 51
4.3.7. R uthenium Partitioning ........................................ ......... ............... 51









4.3.8. Palladium Partitioning ......................................................... .... ........... 52
4.3.9. Tungsten and Molybdenum Partitioning Interactions ............................55
4.3.10. Tantalum and Aluminum Partitioning Interactions.................................57
4.3.11. Tantalum and Aluminum Partitioning Interactions with an Addition of
T titanium ..................................................................................................60
4.4. Segregation B ehavior................................................. .............................. 64
4.4.1. Cobalt Segregation B ehavior................................ ....................... 70
4.4.2. Chromium Segregation Behavior............... ............................................71
4.4.3. Rhenium Segregation Behavior...................................... ............... 75
4.4.4. Tungsten Segregation Behavior ...................................................78
4.4.5. Tungsten Segregation Behavior with an Addition of Molybdenum .........79
4.4.6. M olybdenum Segregation Behavior.............................................. 80
4.4.7. Ruthenium Segregation Behavior............................... ................80
4.4.8. Palladium Segregation Behavior............................................................ 83
4.4.9. Tungsten and Molybdenum Segregation Behavior Interactions ..............83
4.4.10. Tantalum and Aluminum Segregation Behavior Interactions.................87
4.4.11. Tantalum and Aluminum Segregation Behavior with an Addition of
T ita n iu m ...................................... ............................................. 8 8
4.5. Scheil A analysis and Com parison.................................. ...................... ........... 92
4.6. Verification of Applicability of Analysis ............................ ................96

5 DISCUSSION .............................................. ............... 98

5.1. Primary Dendrite Arm Spacing ............................ ....... .................. 100
5.2. Partitioning Coefficient and Segregation...................................... ................ 101
5.2.1. Comparison of k' and K Techniques for Examining Segregation...........101
5.2 .2 C obalt E effects ......... ................................ .................. 105
5.2.3. Chrom ium Effects ............................................................................107
5.2.4. Rhenium Effects ............ ............. .................... 109
5.2.5. Tungsten Effects .................................................... .. ........... ............... 111
5.2.6. Tungsten Effects with an Addition of Molybdenum.............................1113
5.2.7. M olybdenum E effects ............................ ................... .............. ......114
5.2.8. Ruthenium Effects .......................................................................115
5.2.9. Palladium E effects ...................... .............................. ............. .. 117
5.2.10. Tungsten and M olybdenum Effects.................... .................. ................118
5.2.11. Tantalum and Aluminum Effects ..................................... ..................120
5.2.11.1 Effect of increased tantalum with decreased aluminum..............120
5.2.11.2. Effect of decreased tantalum and increased aluminum.............121
5.2.12. Tantalum and Aluminum Effects with an Addition of Titanium ..........123
5.2.12.1. Effect of decreased tantalum with titanium..............................123
5.2.12.2. Effect of decreased aluminum with titanium ...........................125
5.3. Scheil Analysis ........................ .................. ...... ....... 127
5.3.1. Analysis of LMSX-3 ................................................................................... 128
5.3.2. A analysis of C M SX -4 ................................................................... ..... 128

6 CONCLUSIONS ................................. ............... .. ............133









7 F U T U R E W O R K ........................................................................... ..................... 13 8

7.1. Solidification Front Curves from EMPA ......... ........................................ 138
7.2. O their Elem ental Interaction......................................... .......................... 139

APPENDIX

A SAMPLE BACKSCATTERED ELECTRON IMAGES .......................................141

B ELECTRON MICROPROBE ANALYSIS SCHEDULES AND SUMMARY OF
P R O C E D U R E U SE D ....................................................................... ..................160

C AVERAGE ELECTRON MICROPROBE ANALYSES RESULTS ..................163

D SCHEIL ANALYSIS GRAPHS FOR LMSX-3 .............................................1..82

E SCHEIL ANALYSIS DATA AND GRAPHS FOR CMSX-4...............................195

F SCHEIL ANALYSIS GRAPHS FOR LMSX-3 ................................................204

G SCHEIL ANALYSIS DATA AND GRAPHS FOR CMSX-4..............................217

L IST O F R E F E R E N C E S ............. ...... .......... ................ ..............................................226

B IO G R A PH IC A L SK E T C H ........................................ ............................................230
















LIST OF TABLES


Table p

3-1 Compositions of the 18 model alloys in weight percent (wt%) ............................22

3-2 Com position of CM SX -4 in w t% .4,6 ............................................. .....................28

4-1 PDAS measurements from EMPA and from hand calculations. ..........................31

4-2 Showing weight percentages of each respective element in each alloy from the
dendrite core and the interdendritic region, and the calculated k' value for both
techniques A (in orange), and B (in blue). .................................... .................35

4-3 Comparison of values calculated by k'B and K ....................................................73

4-4 Comparison of k'B and K for CMSX-4...............................................................97

5-1 Ki | for the eighteen model alloys and CMSX-4 listed in order from lowest to
highest. ............................................................................ 105

6-1 Elemental segregation effects for each combination of alloy compared.............. 136

7-1 Recommended alloying variations to investigate in wt%. ..................................139

7-2 Recommended alloying variations based on at% ......................................... ......140

C- Average EM PA data for LM SX-1 .............................. ................................. 164

C-2 Average EM PA data for LM SX-2 .............................................. ............... 165

C-3 Average EM PA data for LM SX-3 ........... ................................... .................. 166

C-4 Average EM PA data for LM SX-4. ............................................. ............... 167

C-5 Average EMPA data for LMSX-5 .................................................................168

C-6 Average EM PA data for LM SX-6. ............................................. ............... 169

C-7 Average EM PA data for LM SX-7. ............................................. ............... 170

C-8 Average EM PA data for LM SX-8. ............................................. ............... 171









C-9 Average EM PA data for LM SX-9. ............................................. ............... 172

C-10 Average EMPA data for LMSX-10 ......................................................................173

C-11 Average EMPA data for LMSX-11. ........................................................... 174

C-12 Average EMPA data for LMSX-12 ......................................................................175

C-13 Average EM PA data for LM SX-13 ................................................................... 176

C-14 Average EMPA data for LMSX-14 ......................................................................177

C-15 Average EMPA data for LMSX-15 ......................................................... 178

C-16 Average EM PA data for LM SX-16 ......................................................................179

C-17 Average EM PA data for LM SX-17 ......................................................................180

C-18 Average EM PA data for LM SX-18. ...................................... ....................181

E -l Scheil curve data for CM SX -4 .........................................................................201

F-l EMPA data for LMSX-3 Scheil analysis. ............. ........................................209

G-l Scheil curve data for CM SX-4. ........................................................................223
















LIST OF FIGURES


Figure pge

2-1 The y-y' matrix from model alloy LMSX-15. Image taken at 10kx. y matrix and y'
precipitates are labeled. ............................................... .................. ............. 10

2-2 Al-Ni phase diagram. The A1Ni3 field is visible at 85 87 wt% Ni....................11

2-3 FCC matrix shown above left and Li2 ordered phase ofNi3Al (Ni shown in black)
above right.6 .................................. ............................. .......... .............11

2-4 Ni-Al-X ternary phase diagram. The Ni3Al phase fields are shown in the phase
diagram with the various other additions, indicating large regions of solubility.....14

2-5 The improvements in alloy elongation and rupture strength for the same alloys (M-
252 and Waspalloy) for vacuum melt and air melt. ............................................15

2-6 DS casting operation is shown on the left and SX casting operations are shown on
the right. The primary difference is the use of a constrictor or single crystal
selector. ............................................................................. 17

3-1 BSE image of LMSX-1 taken at 100x equivalent.................................................25

3-2 BSE image of LMSX-13 taken at 100x equivalent............................. ...............25

3-3 BSE photo of LMSX-1 taken at 100x equivalent. Yellow line indicates location of
the line scan reform ed. ................................................ ............................... 27

4-1 BSE image of LMSX-13. Black lines added to image were where PDAS
measurements were taken ................. ......... ..... ............... 30

4-2 k' values for LMSX-1 for techniques A (orange) and B (blue). The green line is at
k' = 1 ..................... ....................................... 40

4-3 k' values for LMSX-13 for techniques A (orange) and B (blue). The green line is
at k = 1 ............................................................................. 4 0

4-4 k' values for LMSX-18 for techniques A (orange) and B (blue). The green line is
at k = 1. .......................................................................... 4 1

4-5 k' values for LMSX-8 for techniques A (orange) and B (blue). The green line is at
k' = 1. The difference is noted by a circle.......................................................41









4-6 Mo segregation plot for LMSX-7 and -8. White points were used in k'B analysis.
Second order trendlines are also shown for both alloys...................................42

4-7 Al segregation plot for LMSX-1 and -18 shown for comparison. White points were
used in k'B analysis. Second order trendlines are also shown for all alloys............42

4-8 Partitioning effects due to increasing Co concentration for elements showing a
preference to segregate to the dendritic region ....................................................... 44

4-9 Partitioning effects due to increasing Co concentration for elements showing a
preference to segregate to the interdendritic region. .........................................44

4-10 Partitioning effects due to increasing Cr concentration for elements showing a
preference to segregate to the dendritic region ....................................................... 45

4-11 Partitioning effects due to increasing Cr concentration for elements showing a
preference to segregate to the interdendritic region. .........................................45

4-12 Partitioning effects due to increasing Re concentration for elements showing a
preference to segregate to the dendritic region ....................................................... 48

4-13 Partitioning effects due to increasing Re concentration for elements showing a
preference to segregate to the interdendritic region. .........................................48

4-14 Partitioning effects due to increasing W concentration for element segregating to
th e d en dritic reg ion ............ ... ............................................................ ....... ............... 4 9

4-15 Partitioning effects due to increasing W concentration for element segregating to
the interdendritic region ........................................ ............................................49

4-16 Partitioning effects due to decreasing W concentration with the addition of 1 at%
Mo for element segregating to the dendritic region. ..............................................50

4-17 Partitioning effects due to decreasing W concentration with the addition of 1 at%
Mo for element segregating to the interdendritic region .......................................50

4-18 Partitioning effects due to the addition of 1 at% Mo for element segregating to the
dendritic region .................................................... ................. 53

4-19 Partitioning effects due to the addition of 1 at% Mo for element segregating to the
interdendritic region. ........................ .......... .. ...... ............... 53

4-20 Partitioning effects due to Ru addition for element segregating to the dendritic
re g io n ...................................... .................................... ................ 5 4

4-21 Partitioning effects due to Ru addition for element segregating to the interdendritic
re g io n ...................................... .................................... ................ 5 4









4-22 Partitioning effects due to Pd addition for element segregating to the dendritic
re g io n ...................................... .................................... ................ 5 6

4-23 Partitioning effects due to Pd addition for element segregating to the interdendritic
re g io n ...................................... .................................... ................ 5 6

4-24 Partitioning trends for elements in LMSX-1 and-7. Difference in the two alloys is
that LMSX-7 contains 3.1 wt% W and an addition of 1.6 wt% Mo......................58

4-25 Partitioning trends for elements in LMSX-6 and -8. Difference in the alloys is that
LMSX-6 contains 8.6 wt% W, 0 wt% Mo, and LMSX-8 contains 5.85 wt% W, 1.6
w t% M o .......................................................... ................. 58

4-26 Partitioning trends for elements between in LMSX-1 and-12. Difference in the two
alloys is that LMSX-12 contains 11.2 wt% Ta and 5.0 wt% Al. ...........................61

4-27 Partitioning trends for elements between in LMSX-1 and-13. Elements segregating
to the dendritic region shown. Difference in the two alloys is that LMSX-13
contains 6.00 wt% Ta and 6.15 wt% Al........................................ ............... 61

4-28 Partitioning trends for elements between in LMSX-1 and-13. Elements segregating
to the interdendritic region shown. Difference in the two alloys is that LMSX-13
contains 6.00 wt% Ta and 6.15 wt% Al....................................... ............... 62

4-29 Partitioning trends for elements between in LMSX-12 and-13. Elements
segregating to the dendritic region shown.............. .............................................. 62

4-30 Partitioning trends for elements between in LMSX-12 and-13. Elements
segregating to the interdendritic region shown. ........................................... ........... 63

4-31 Partitioning trends for elements between in LMSX-1 and-14. Elements segregating
to the dendritic region shown. Difference in the two alloys is that LMSX-14
contains 6.00 wt% Ta and an addition of 0.80 wt% Ti. ................. .................65

4-32 Partitioning trends for elements between in LMSX-1 and-14. Elements segregating
to the interdendritic region shown. Difference in the two alloys is that LMSX-14
contains 6.00 wt% Ta and an addition of 0.80 wt% Ti. ................. .................65

4-33 Partitioning trends for elements between in LMSX-1 and-15. Elements segregating
to the dendritic region shown. Difference in the two alloys is that LMSX-15
contains 5.10 wt% Al and an addition of 0.80 wt% Ti. .........................................66

4-34 Partitioning trends for elements between in LMSX-1 and-15. Elements segregating
to the interdendritic region shown. Difference in the two alloys is that LMSX-15
contains 5.10 wt% Al and an addition of 0.80 wt% Ti. .........................................66

4-35 Partitioning trends for elements between in LMSX-14 and-15. Elements
segregating to the dendritic region shown.............. .............................................. 67









4-36 Partitioning trends for elements between in LMSX-14 and-15. Elements
segregating to the interdendritic region shown. ........................................... ........... 67

4-37 Red lines indicated solidification/segregation gradients between dendrite cores
within the interdendritic region for an element that segregates to the dendrite cores.
The dendrites are represented in yellow .... ........... ...................................... 69

4-38 Elemental segregation plots based on K due to increasing Co content from 4 wt% to
12 .2 w t% ........................................................................ 7 5

4-39 Elemental segregation plots based on K due to increasing Cr content from 2.1 wt%
to 6 .15 w to% ....................................................... ................. 76

4-40 Elemental segregation plots based on K due to increasing Re content from 0 wt% to
8.9 w t% .......................................................... 78

4-41 Elemental segregation plots based on K due to increasing W content from 5.85 wt%
to 8 .6 w to% ........................................................ ................. 79

4-42 Elemental segregation plots based on K due to increasing W content from 3.1 wt%
to 5.85 wto with an addition of 1.6 wt% Mo to the alloys...................................82

4-43 Element segregation plots based on K due to increasing Mo content from 0 wt% to
1 .6 w t% ......................................................................... 8 2

4-44 Element segregation plots based on K due to increasing Ru content from 0 wt% to
3 .2 w t% ......................................................................... 8 4

4-45 Elemental segregation plots based on K due to increasing Pd content from 0 wt% to
1 .7 w t% ......................................................................... 8 4

4-46 Elemental segregation plots based on K due to decreasing W to 3.1 wt% and adding
1.6 w t % M o. ..........................................................................86

4-47 Elemental segregation plot based on K due to decreasing W to 5.85 wt% and
adding 1.6 w t% M o. ....................................... ... .... ........ ......... 86

4-48 Elemental segregation plots based on K due to increasing Ta to 11.2 wt% and
decreasing A l to 5 w t% ............................................ ................... ............. 89

4-49 Elemental segregation plots based on K due to decreasing Ta to 6.0 wt% and
increasing Al to 6.15 wt% ....... ........................... .......................................89

4-50 Elemental segregation plots based on K due to changing Ta and Al concentrations.
Compilation of Figures 4-48 and 4-49. ................. .............................................. 90

4-51 Elemental segregation plots based on K due to decreasing Ta to 6.0 wt% and a Ti
addition of 0.80 w t% ............................ ........................... .......... ................93









4-52 Elemental segregation plots based on K due to decreasing Al to 5.10 wt% and a Ti
addition of 0.80 w t% ........................ ................................ ......... ...... ............93

4-53 Elemental segregation plots based on K due to changing Ta and Al concentrations
with a Ti addition. Compilation of figures 4-51 and 4-52. ................ ..............94

4-54 Scheil curve comparison for Cr done by two different techniques........................94

4-55 Scheil curve comparison for Re done by two different techniques..........................95

4-56 Scheil curve comparison for Ta done by two different techniques........................95

5-1 Ni segregation plot for LMSX-9, -10, -1, and -11. Trendlines were added to show
degree of segregation ofNi observed as the Re content was increased...............103

5-2 Ta segregation plot for LMSX-9, -10, -1, and -11. Trendlines were added to show
degree of segregation of Ni observed as the Re content was increased...............103

5-3 Example showing data for k' and K from two idealized elemental segregation
profiles based on a normalized PDAS. The equations for each trendline are
indicated on the graph. ................................ .... .......... .............. .............. 104

5-4 LMSX-3 Scheil curves for Full and Short techniques for Cr.............................130

5-5 LMSX-3 Scheil curves for Full and Short techniques for Al.............................130

5-6 Scheil curves for Re from CMSX-4 done using the techniques described in this
stu d y ...............................................................1 3 1

5-7 Scheil curves for Re from CMSX-4 from literature.43 ...........................131

5-8 Scheil curves for Ta from CMSX-4 done using the techniques described in this
stu d y ...............................................................1 3 1

5-9 Scheil curves for Ta from CMSX-4 from literature.43 ......................................131

5-10 Scheil curves for Ti from CMSX-4 done using the techniques described in this
stu d y ...............................................................1 3 2

5-11 Scheil curves for Ti from CMSX-4 from literature.43..........................................132

5-12 Scheil curves for W from CMSX-4 done using the techniques described in this
stu d y ...............................................................1 3 2

5-13 Scheil curves for W from CMSX-4 from literature.43.......................................132

A-1 BSE image of LM SX-1 at 100x. ..........................................................................142

A-2 BSE image of LM SX-1 at 100x. ..........................................................................142









A-3 BSE image of LM SX-2 at 100x. ......................................................................143

A-4 BSE image of LM SX-2 at 100x. ......................................................................143

A-5 BSE image of LM SX-3 at 100x. ......................................................................144

A-6 BSE image of LM SX-3 at 100x. ......................................................................144

A-7 BSE image of LM SX-4 at 100x. ......................................................................145

A-8 BSE image of LM SX-4 at 100x. ......................................................................145

A-9 BSE image of LM SX-5 at 100x. ......................................................................146

A-10 BSE image of LM SX-5 at 100x. ......................................................................146

A-11 BSE image of LM SX-6 at 00x. ......................................................................147

A-12 BSE image of LM SX-6 at 100x. ......................................................................147

A-13 BSE image of LM SX-7 at 00x. ......................................................................148

A-14 BSE image of LM SX-7 at 100x. ......................................................................148

A-15 BSE image of LM SX-8 at 100x. ......................................................................149

A-16 BSE image of LM SX-8 at 100x. ......................................................................149

A-17 BSE image of LM SX-9 at 00x. ......................................................................150

A-18 BSE image of LM SX-9 at 00x. ......................................................................150

A-19 BSE image of LMSX-10 at 00x. .........................................................................151

A-20 BSE image of LMSX-10 at 00x. .........................................................................151

A-21 BSE image ofLMSX-11 at 00x. ......................................... ............... 152

A-22 BSE image ofLMSX-11 at 00x. ......................................... ............... 152

A-23 BSE im age of LM SX-12 at 100x ...................................................... ........... 153

A-24 BSE image of LMSX-12 at 100x. ............................ ..................... 153

A-25 BSE image of LMSX-13 at 00x. ...................................................... ...............154

A-26 BSE image of LMSX-13 at 00x. ...................................................... ...............154

A-27 BSE image of LMSX-14 at 100x. .................................. ............... 155









A-28 BSE image of LM SX-14 at 100x. ...................................................... ............... 155

A-29 BSE image of LM SX-15 at 00x. ......................................................................... 156

A-30 BSE image of LM SX-15 at 00x. .........................................................................156

A-31 BSE image of LMSX-16 at 00x........................................................... 157

A-32 BSE image of LMSX-16 at 100x. .........................................................................157

A-33 BSE image of LM SX-17 at 00x. .........................................................................158

A-34 BSE image of LM SX-17 at 100x. .........................................................................158

A-35 BSE image of LM SX-18 at 00x. ...................................................... ............... 159

A-36 BSE image of LM SX-18 at 00x. ...................................................... ............... 159

E-1 Scheil curve for Ni from CMSX-4. ...............................................................196

E-2 Scheil curve for Cr from CMSX-4. ...............................................................196

E-3 Scheil curve for Co from CM SX-4. ............................................ ............... 197

E-4 Scheil curve for Mo from CMSX-4. ........................................... ............... 197

E-5 Scheil curve for W in CM SX -4 ........................................................... ... .......... 198

E-6 Scheil curve for Re in CM SX-4. ........................................ ........................ 198

E-7 Scheil curve for Ta from CM SX-4..................................... ........................ 199

E-8 Scheil curve for Al from CMSX-4 ................... ....... ............. 199

E-9 Scheil curve for Ti from CM SX -4 .............................................. .....................200

F-l Scheil curves comparing full and short techniques for Ni in LMSX-3.................205

F-2 Scheil curves comparing full and short techniques for Cr in LMSX-3.................205

F-3 Scheil curves for both full and short techniques for Co in LMSX-3 ....................206

F-4 Scheil curves for both full and short techniques for W in LMSX-3 .....................206

F-5 Scheil curves for both long and short techniques for Re in LMSX-3....................207

F-6 Scheil curves for both long and short techniques for Ta in LMSX-3....................207

F-7 Scheil curves for both full and short techniques for Al in LMSX-3 ......................208









G-1 Scheil curve for Ni from CMSX-4. ........................................................................218

G-2 Scheil curve for Cr from CMSX-4. ........................................................................218

G-3 Scheil curve for Co from CMSX-4. ........................................ ..................... 219

G-4 Scheil curve for Mo from CMSX-4. ............................................. ............... 219

G -5 Scheil curve for W in CM SX -4 .......................................................................... 220

G-6 Scheil curve for Re in CMSX-4. ........................................ ......................... 220

G-7 Scheil curve for Ta from CM SX-4...................................... ......................... 221

G-8 Scheil curve for Al from CMSX-4. ........................................................................221

G-9 Scheil curve for Ti from CMSX-4. ........................................ ...................... 222


xviii















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree Masters of Science

A NEW METHOD FOR THE MODELING OF ELEMENTAL SEGREGATION
BEHAVIOR AND PARTITIONING IN SINGLE CRYSTAL NICKEL BASE
SUPERALLOYS

By

Eric Christopher Caldwell

August 2004

Chair: Gerhard Fuchs
Major Department: Materials Science and Engineering

Ni-base superalloys are commonly used in very extreme environments where high

temperature strength, good corrosion/oxidization resistance, and microstructural stability

are required. These superalloys are made up of twelve to fifteen different elemental

additions including, but not limited to, Cr, Co, Mo, W, Re, Ta, Al, Ti, Ru, and Pd. The

combinations of these elements make casting of a superalloy difficult and undesirable

phases (the Topologically Close Packed, or TCP phases) may form in the microstructure

during casting or service.

TCP phases form due to localized concentrations of specific elements. To prevent

the formation of these undesirable phases and to maximize the alloys' properties,

solutioning heat treatments are required. Many of the solutioning heat treatment for third

generation superalloys (2 at%/ Re) are very long. The length of time has to be sufficient

to remove the elemental segregation that exists within the microstructure.









The elemental segregation exists upon casting due to alloying elements partitioning

to a specific phase (y or y') or region (dendrite core or interdendritic region). A

partitioning coefficient, k', is used to describe the partitioning behavior of the alloying

elements. k' was observed to exhibit a different partitioning behavior than was indicated

by electron microprobe line scans.

A new term based on the curvature of the segregation plot, K was used to qualify

the direction of each elements' partitioning (dendrite core or interdendritic region), and to

quantify some degree of relative segregation between all the alloying elements in each

alloy. The values for K were then plotted against varying elemental relationships and

conclusions about the segregation behavior were drawn.














CHAPTER 1
INTRODUCTION

The need for new materials is ever present and has been a driving force in

technological evolution. The gas turbine engine is a prime example of this. Due to the

extreme operating conditions within the engine, most materials as well as the processes

used to fabricate components are insufficient.

Historically the first true application of gas turbine technology was the first jet

aircraft of World War II. These aircraft were revolutionary at the time, but severely

limited operationally and cost prohibitive due to materials issues. The IME-262, the first

jet powered airplane, was powered by a Junkers Jumo 004B (Figure 1-1) turbojet engine,

generating about 2,000 pounds of thrust. However, the engine could only run for around

forty hours before it had to be replaced. This short service life was largely due to the



II


JL]770Tm


Figure 1-1: Junkers Jumo 004A turbojet engine









forged steels used in the engine. After World War II, the jet age began, and with it the

quest for higher powered and more reliable turbojet engines.

One of the key limiting components of the turbojet engine (or more simply here,

turbine) are the blades and vanes within the "hot section". The "hot section" is as the

name implies: the hot part of the engine. A turbojet operates under the thermodynamic

Brayton cycle. The efficiency of a Brayton cycle is determined by the temperature of the

first stage of the turbine. The higher the temperature of the first stage, the more efficient

and higher power the turbojet can become. Since more power is desired and the limiting

components are in the region of the turbine section, these components had to be designed

better and new materials used to reach the higher temperatures required to increase

efficiency.

The Junkers Jumo 004B blades were made of forged mild steel (SAE 1010) that

had an aluminum coating for oxidization protection.3 It should be noted that the use of

steel over other metals was due to availability of steel compared to other scarce strategic

materials. Besides being exposed to the highest temperatures within the engine, the

blades and vanes are also exposed to a very corrosive environment and at high stress

levels. This lead the early metallurgists to select the Co-based and Ni-based metals for

turbine applications, which are now called superalloys (Figure 1-2).

Many of the early improvements to superalloys came from both processing and by

alloying. The concept of investment casting was taken from the dental industry. With

this innovation came problems such as inclusions from the mold, but investment casting

was cheaper and easier to manufacture than forged components. The advent of vacuum

induction melting (VIM) by F. N. Darmara in the 1950's reduced the problem of















1100 Ta +Hf DS eutectics
Cast alloys +WandNb / IN591 DS e CMS
0 MAR M-22 I/MAR-M-002 DS CMSX-2
c ^'- MAR-M-20 j 0
10".MARM-200 /M2 M241 M24 MAf-M-200+ HfDSN
1 0 00 INlOO .---TRWVIA W --R J
S119 R INN792 IN 201 N620
Smelting l 713C C] R77 I. 3
M Udlmet 700 N11l [ IN 73B IN 935
S +0 Udlmet50 MA6R-M- ~ U t7
E*+co N1_1 '0 ..... /-
900 Waspaloy Ni l
SX40 / N90
12 N91
X750 / NB1A wrought 1Cast N1i-bse
h +AI a l I l Go-base
's NI-base
800 / HS21 u81 Wrought c0 C-bae
N0 ---- +Ti Cast L DS and SC
Hastelloy B P/M A ODS Ni-base

700 --- 199-/
1940 1950 1960 1970 1980 1990s
Figure 1-2: The change of temperature capabilities for superalloys at the approximate
time the alloy was introduced.4

inclusions to wrought processes.5 VIM made casting an even more viable alternative


because purer alloys could be made with fewer inclusions. As an added benefit, additions


of more reactive additions for solid solution strengthening (i.e., W, Nb, and later Ta)4


could be used due to the vacuum atmosphere in the processing stage. Therefore better


strength and creep resistance, and ultimately higher temperature capability, were realized


in the resulting alloys.


One of the first superalloys was Ni-20Cr, a simple solid solution strengthened


alloy. To increase the strength of this alloy, metallurgists began to add other alloying


elements, like Mo and C, to the Ni-Cr base alloy. The demand for higher temperature use


was still present, and since Cr depressed the Ni melting point, other alloying elements


such as Al had to be utilized. The Ni-Al alloys worked well with the VIM process due to


the reactivity of Al with the atmosphere and the need to keep Al in solution.


There were two potential precipitate strengthening phases that could be used for the


nickel-aluminum alloys: P-NiAl, and y'-Ni3Al. Initially, the Ni-base alloys were single


Directional
structures


MA6000









phase y, due to the FCC lattice which provided good creep resistance. It was later found

that a y matrix with y' (y' is an order phase with an L12 type structure) precipitates

produced higher strength materials and allowed operational temperatures to increase

further. The y' phase forms as a cuboidal precipitate, but the shape of the precipitate is

governed by the misfit strains between the precipitates and the matrix.6 Negative misfit

produces small cubes, and positive misfit produces spheres. A significant portion of the

strengthening of the alloys is from the y' phase, the y-y' interface, and single y' coherent

with the y matrix. The aluminum also resulted in the formation of a thin A1203 coating

on the surface which reduced the problems of corrosion in the hot sections. The resulting

alloys were the first generation superalloys. All of the elements that had previously been

added to the matrix when steels and other metals were used (i.e., Cr, W, Nb, Ti, Ta, etc.),

were all added to these new alloys. The resulting Ni-based alloys could be used up to

about 85% of their homologous temperature.4

The entire time alloy development was in progress, the processing advances were

also occurring. Due to the high temperatures, turbine blades must also withstand creep; a

slow time-temperature-stress dependant type of deformation. Investigation found that

creep life could be extended by reducing the number of transverse grain boundaries

within the component. The number of transverse grains was reduced with the

development of directional solidification in 1960.6 Directional solidification (DS) itself

was further developed by controlling the withdrawal rate of the casting, and therefore

controlling the solidification front to yield only high angle boundaries (HAB) and low

angle boundaries (LAB)7 along the direction of grain growth.









DS work was not the last of the advancements in processing. The ultimate goal of

DS was the complete elimination of grain boundaries from the cast component, to

produce a "single crystal". This was accomplished with the addition of a grain selector.8

This grain selector almost completely eliminates the HAB's and LAB's from the casting

and produces a single crystal (SX). SX technology further increased the operating

temperatures and operational lifetimes of components within a turbine.

The next key innovation was the addition of rhenium to the alloy. With the

addition of 1 atomic percent (at%) Re, there was a substantial boost in the mechanical

properties of the cast alloys. These alloys containing 1 at% Re became known as second

generation superalloys.

It is often said that "Necessity is the mother of invention," and the desire for better

operational capabilities of turbines was still the quest. Around the mid 1990's another 1

at% of Re was added to the superalloys.9 These were given the moniker of third

generation superalloys due to their Re addition, which resulted in a further increase in the

properties of the alloy. Throughout these alloy and process improvements, engineers and

designers took advantage of the increased temperature capabilities of the blade and vane

alloys. Due to the increased temperature capabilities of the materials, engine design has

taken off more. The F-119 turbojet engine is currently the state of the art and generates

35000 pounds of thrust (Figure 3).10 A very large increase when compared to that of the

early Jumo 004B (an increase of about 18 x in only 50 years).

Due to the increased additions of many high density refractory elements (nearly

20% of the weight was due to less than 10% of the additions), a relatively minor problem

began to becomes more significant. Undesirable phases began to form in the




















Figure 1-3: A modern day turbojet engine. This is the F-119 engine developed by Pratt
& Whitney for the F-22 Raptor and the F-35 Joint Strike fighter.

microstructure along specific orientations. These phases are called topologically close

packed (TCP) phases. While they did form in the earlier generation superalloys, TCP has

become more of a problem in the third generation superalloys. TCP's form at relatively

high temperature, over extended time, consists primarily of the heavy refractory

elements, and form within the microstructure of components in service. There are cases

of TCP forming upon casting (i.e. CMSX-10), but these TCP phases can be put back into

solution by solutioning heat treatments. Some of these solutioning heat treatments are

exceedingly long and take over fifty hours11 to complete. TCP are composed of many of

the refractory elements added to the alloy for strengthening, and the presence of the TCP

therefore depletes the microstructure of the key solid solution strengthening elements.

Also, TCP are inherently brittle, and are reported to be common failure initiation sites in

failed components.4

TCP are needlelike in shape when viewed in the transverse direction and disk like

when observed from the proper longitudinal orientation. Some of the common TCP

phases are o, [t, r, p, and Laves phases.12 Although relatively little is understood about

TCP formation, an understanding of the elemental partitioning during solidification could









aid in TCP prediction, alloy development, and develop better heat treatment

requirements.

Earlier analysis involved the use of a segregation partitioning coefficient, k'. This

partitioning coefficient relates the difference in the amount of an element present between

the dendrite core and the interdendritic region and has been defined as13


k'= XDendte (equation 1-1)
i,Interdendntc

where xi, dendrite is the composition in the dendrite core (in wt%) for element i, and xi,

interdendritic is the composition of element i within the interdendritic region (in wt%). Other

work has utilized partitioning coefficients by performing a Scheil analysis on the data

collected.

It is the goal of this investigation to further examine the elemental partitioning that

takes place during the solidification of a superalloy. To do this a different technique was

used to collect the data in the effort to determine how composition effects elemental

segregation. This different technique was then compared against prior work done, and

was re-examined to identify any new trends.

Two additional checks were also done. The first was Scheil-type analysis that was

preformed on one of the model alloys to see how the data collection technique in this

study compared to that typically preformed in industry. The second check done in this

investigation was then preformed on a common, commercial superalloy to determine how

the analysis used in this study compares to what is reported in open literature.

Using the compositional data collected, this new analysis technique which used

the curvature of compositional profile of the elemental segregation from dendrite core to

dendrite core. This was be done in hopes of developing a better understanding of






8


elemental segregation in a superalloy on solidification in order to develop more castable

alloys with reduced heat treatment requirements, and create new and better alloys for

future use.














CHAPTER 2
LITERATURE SEARCH

Ni-base superalloys are some of the most complex metal alloys used, and are used

in very extreme, if not hostile environments. The metallurgy of superalloys begins with

the microstructure that results from the elemental additions, and then casting and

processing. The processing of these advanced alloys has to be carefully controlled and

the steps understood to produce the optimal balance of properties and to avoid the

formation deleterious phases and an inhomogeneous microstructure. There are

inhomogentities in the elemental distribution that occur on casting of the advanced

superalloys due to elemental partitioning and segregation. This section will provide an

overview of this history and present current ideas regarding the phenomena of

segregation in third generation Ni-base superalloys.

2.1. Evolution of Nickel Based Superalloys

The development of Ni-base superalloys begins nearly 100 years ago. A simple

wrought Ni-20Cr alloy was used for electrical heating elements. They have grown

tremendously from this humble beginning and have spread in their use from heating

elements, to corrosion resistant alloys, and to high temperature applications. A specific

high temperature application for Ni-base alloys is the hot section components of aircraft

turbine engines, and industrial gas turbine (IGT) engines. The Ni alloys developed for

use in these components need to have excellent strength, creep resistance, and fatigue

resistance at high temperature, and also be resistant to oxidation and hot corrosion. The








development of these alloys requires unique alloying additions and special casting and

processing techniques.

2.1.1. The y-y' Matrix

The ability for Ni-based superalloys to tolerate high levels of alloying without

forming microstructural instabilities, and to form the unique y-y' microstructure produces

a material with unique properties. The material is composed of two phases, a y matrix

with y' precipitates spread throughout, with a coherent interface between the phases

(Figure 2-1). Figure 2-2 is the Al-Ni phase diagram showing the specific composition

range of interest for the formation of these alloys.14 The y matrix is a FCC structure and

the y' is an L12 type ordered structure (Figure 2-3). The FCC structure exhibits the

highest degree of packing with numerous slip systems which typically results in a

material that maintains arrangement for constituent atoms to maintain tensile, creep

rupture, and fatigue strength, at temperatures close to the homologous temperature.





I I---'-\ \


v


Figure 2-1: The y-y' matrix from model alloy LMSX-15. Image taken at 10kx. y matrix
and y' precipitates are labeled.










The FCC lattice also has a large range of solubility for other elements that can be used to

improve the properties of the alloy. The y' precipitate has nearly the same lattice


parameter as the y matrix making the matrix and precipitate coherent.

ALiomic PFI-L;r.n Nickel
0 Io 20 30 40 50 40 s S0 .100

1800

1500

1400 3
10L


AINL



I -








o 20 2) 3 0 40 s0 o SO o eo 9fl tOO
Al Weight Percent NLcke] Ni

Figure 2-2: Al-Ni phase diagram. The A1Ni3 field is visible at 85 87 wt% Ni.










Figure 2-3: FCC matrix shown above left and L12 ordered phase of Ni3Al (Ni shown in
black) above right.6

The benefits of the FCC or y matrix were originally discovered in steels and were

found to have the ability to be heavily alloyed. The base element for high temperature

alloys was shifted from Fe to Ni and Co because they had the ability to be alloyed to a

greater extent and the y-y' microstructure could be formed. Cr and Al were some of the









earliest additions to this base material. They acted as solid solution strengtheners,

increased environmental resistance, and increased the high temperature properties of the

alloys. The addition of Cr to the matrix increased the alloys resistance to hot corrosion,

and Al increased its resistance to high temperature oxidation.4'6

The high strength of the superalloys comes from solid solution strengthening,

precipitation hardening, and the misfit between the y and its coherent ordered

precipitated, y'. When alloying elements are added, the lattice parameters for the y and y'

both change slightly due to the alloying elements being larger or smaller than the one

they are substituting for (Hume-Rothery criteria for solid solution strengthening). The

misfit is the difference in lattice parameters between the matrix and the precipitate.

Misfit influences the shape of the y' precipitate. At low misfit strains (0.0 0.2 %), the y'

precipitates are spherical. At slightly higher misfit strains (0.5-1.0 %), the y' precipitates

are cuboidal. Finally, when the misfit is even higher (> 1.25 %), the y' precipitates are

plate-like. It is the formation of the cuboidal y' and the very fine (secondary) y' (which is

formed on ageing) that prevents dislocation bypass and forces the dislocations to 'cut'

through the ordered y' particle forming a superdislocation. The y' volume fraction is also

important because it influences alloy strength4. Alloys that have a very high y' volume

fraction (z 70% and greater) exhibit high strength, but very limited ductility, and the

opposite is true for the low y' volume fraction alloys. It is the combination of the volume

fraction, misfit, and coherency of the precipitate that bring about the high strengths of

superalloys.

There are many different elemental additions used to improve the properties of

superalloys. Among the additions are Co, Cr, Mo, W, Re, Ta, Ti, Ru, and Pd (which has









become of recent interest). Many of these elements are soluble in the Ni3Al system

(Figure 2-4).30 Each addition has various contributions it provides to the superalloy as a

whole, and summarized below

* Cobalt: Added to reduce or offset the y' solvus temperature without causing
incipient melting4'6'15, is reported to increase the microstructural stability of the
alloy9'15, reduces stacking fault energy (YSFE), and provides some solid solution
strengthening.6 Co has been reported to partition to the dendrite core.16,17,18

* Chromium: Added to increase the surface stability and prevent/minimize hot
corrosion4'6, reduces the y' solvus temperature19, reduces the anti-phase boundary
energy (YAPB) of the y' phase. Cr has been to partition to the dendrite core16'17'18 and
is a known component of TCP phases.4'6

* Molybdenum: Added to increase solid solution strengthening of the y' matrix6'18,
lower the alloy density (Mo is less dense than other elements like W), adjust the y'
volume fraction.20 Mo has been reported to partition to the dendrite core16'18'21, and
is a known component of TCP phases.4'6'12

* Tungsten: Added because it is a potent solid solution strengthener in Ni-base
alloys16'18, and W increases the incipient melting point of the alloy. W partitions to
the dendrite core and is a known component of TCP phases.6'12 W has also been
reported to increase the susceptibility of the alloy to hot corrosion.

* Rhenium: is the element that defines the difference in superalloy generations. It is
a strong solid solution strengthener22, and increases the high temperature creep
properties.18 Re is an element found in TCP phases23 and partitions to the dendrite
core.17,19,25
core.

* Tantalum: like Re is a strong solid solution strengthener.18'25 Ta is also added to
improve castability26, increase the y' volume fraction15, decreases the susceptibility
to incipient melting27, increase the anti-phase boundary energy (YAPB) of the y', and
is one of the y' former. Ta has been reported to partition to the interdendritic
region.16,18,22

* Aluminum: is the primary y' former.4'6 Al is also added to increase surface
stability and high temperature oxidation resistance4'6, and Al improves the
castability of the alloy. Al has been reported to partition to the interdendritic
region. 16'1822

* Titanium: another y' former.4'6 Ti is less dense than Ta, it increases the y' volume
fraction15, increase the anti-phase boundary energy (YAPB) of the y', and strengthens
the y' phase.4'6'16 Ti has been reported to partition to the interdendritic region.16'18










* Ruthenium: is reported to increase the microstructural stability28 and act as a solid
solution strengthener. Ru has been reported to partition to the dendrite core.16,29

* Palladium: is an element of recent investigation. Pd is added to improve the
surface stability of the alloy and act as a solid solution strengthener. Pd has been
reported to partition to the dendrite core.16'29

There are other trace elements (i.e. Hf, and B) that are added as well as many

deleterious elements (i.e. Cd, Hg, 0, and N) that have to be removed by meticulous

quality control and specialized processing procedures.

550










s4







Xs~O 40 30 A/. X 2O 10

Figure 2-4: Ni-Al-X ternary phase diagram. The Ni3Al phase fields are shown in the
phase diagram with the various other additions, indicating large regions of
solubility.

2.1.2. Casting and Specialized Processing Techniques

The original superalloys were cast using investment casting techniques from dental

prosthesis.6 Investment casting involves the pouring of the molten alloy into a pre-

formed shell mold and then breaking the shell mold away from the components after the

alloy has solidified and cooled. This left behind grains of various sizes throughout the

alloy due to different localized cooling rates. In some instances, inclusions were left in










the casting from the shell, impurities in the metal melted, or some of the alloying

elements oxidizing before the alloy solidifies (i.e. 2 Al + 3/2 02 -> A1203). For the

properties of the superalloys to increase, these problems had to be overcome.

Vacuum induction melting (VIM) overcame these problems. Developed in the

1950's by Falih N. Darmara6, VIM removed the atmosphere to keep the reactive

elements (i.e. Al and Ti) from oxidizing and leaving inclusions in the cast alloys, and

aided in removing of some of the deleterious tramp elements from the alloys. VIM also

allowed for closer control of the elemental additions. The mechanical properties

increased after VAR was used. (Figure 2-5).4

s- 50
40






M-252 V4Walsp M-252 Wapalovy
Elongalion Rupturle Slenglh
i Ai r mlt O Vcuurnmanu
Figure 2-5: The improvements in alloy elongation and rupture strength for the same
alloys (M-252 and Waspalloy) for vacuum melt and air melt.

Superalloy properties were increased with the advent of VIM and VAR, but another

advancement had to achieved to continue to increase the useful temperatures and

mechanical properties as turbine inlet temperatures continued to rise. The presence of

transverse grain boundaries was reduced with the use of directional solidification (DS).

The DS process was initially developed in the 1960's by F. VerSnyder and colleges

working at Pratt & Whitney.6 The process used was then further improved upon by G.

Chadley working at TRW.7 The improvement involved a controlled withdrawal of the

casting from the furnace. The grains nucleate on the chill plate and grow into the melt,









but the solidification interface does not change location relative to the outside of the

furnace. The solidification interfaces only moves relative to the component as it is being

cast. By controlling the withdrawal rate, which controlled the solidification front, the

only grains formed in the casting are only high angle boundaries (HAB) and low angle

boundaries (LAB).

The removal of transverse grain boundaries dramatically increased the creep

properties of the alloys. The next goal was the elimination of grain boundaries from the

alloy entirely. B. Piearch modified the molds being used for DS. He added a "grain

selector" to the lower part of the casting. This grain selector was designed to let only on

grain orientation through. This is typically the <001> orientation due to its high creep

rupture properties. When the alloy was now cast, it was a single crystal (SX) with no

longitudinal or transverse grains. Figure 2-631 shows the configuration for DS casting

techniques and Figure 2-731 shows the configuration for SX casting techniques.

As the superalloys were being cast, they began to develop a problem. A metastable

phase would develop in the microstructure over time while the alloy was in-service or on

casting due to the high refractory element content. These phases are the topologically

close packed (TCP) phases and they deplete the matrix of alloying elements when they

are formed from the constituent alloying elements.12 TCP are thought to be fracture

initiation sites due to their shape and brittle behavior. Methods like PHACOMP were

developed to create alloys that had stable microstructures that were stable (i.e., were not









Susceplor Induction
Insulation | ___ .... ..... Coil
nsulation Susceptor Induction Radil /
coil Radtilobn 0/
Sh. / ean
I Radiation
heating 0
0 0

0 Mea
0 Molten 0 mi 0
metal Rd aton Baffel
c000ing//, / Single
Ceramic Radiation Crysal
mold /, cooling Cea Crystal
mold Selector
Solidification 00 o Water-cooled Columnar grain
front chill Wateroot-led Starter Block
Motion
Figure 2-6: DS casting operation is shown on the left and SX casting operations are
shown on the right. The primary difference is the use of a constrictor or single
crystal selector.

prone to form TCP phases). As more and more refractory elements were added to the

alloy, the frequency of TCP formation increased. TCP formation was noted in some of

the early superalloys during service life, but in alloys like CMSX-10, TCP phases form

on casting due to the high refractory element content. Solutioning heat treatments are

done to remove the TCP phases from the as-cast alloys but these heat treatments are

very long (upwards of 50 hours), at high temperature (CMSX-10 is solution heat treated

at temperatures above 13500C).16 There are several different TCP phases found in

superalloys. Among these are o, |t, p, r, and the Laves phases. o and p are composed

predominately ofNi Cr, and Re, and to a lesser extent Co, W, and Mo.12

When a SX component is cast, a solidification front is formed as the dendrites grow

into the melt. The dendrites reject certain elements back into the liquid depending up

how the elements partition. This rejection is the origin of the segregation of the alloying

elements within the microstructure. With the elements not being homogeneously

distributed in the alloy, solutioning heat treatments must be preformed.









Solutioning heat treatments (solutioning for short) are done at temperatures above

the y' solvus temperatures and below the solidus temperature and at times sufficient to

have the elements become evenly distributed. The difference in these two temperatures

(y' solvus and solidus temperatures) is called the y' window. In general, alloys that have

less segregation are more easily solutioned.

There are several benefits to developing a better understanding of the segregation

of the constituent elements in a nickel base superalloy. By understanding which elements

segregate more strongly, solution heat treatments can be developed that are potentially

shorter and at lower temperature. The development of new alloys would also benefit

from this understanding, by using elements that have been shown to reduce segregation,

and therefore, reduce TCP formation.














CHAPTER 3
MATERIALS AND EXPERIMENTAL PROCEDURE

In this chapter, the materials and procedure that were used in this study are

described along with the various techniques used to analyze them.

3.1. Materials

The materials used are based on a third generation Ni-based superalloy. The

baseline alloy (LMSX-1); has a composition in weight percent (wt%) of Ni-bal, Cr-4.15,

Co-12.2, W-5.85, Re-5.9, Ta-8.6 Al-5.5, Hf-0.1. The baseline composition is related to

CMSX-10 and Rene N6, both being third generation superalloys. From this LMSX-1

baseline alloy, 17 other model alloys were designed to evaluate the effect of typical

alloying additions on the solidification behavior and properties ofNi-base superalloy

single crystals (Table 3-1). The elemental additions and the compositional ranges

selected were based on industrial experience, material development history, and current

industrial trends.

The 17 model alloys each had one to two variations from the baseline alloy so that

the influence of each type of addition could be examined. LMSX-2 and -3 were added to

study the influence of cobalt on stability, y' solvus and solid solution strengthening.

LMSX-2 contained a moderate level of Co (8 w/o) and LMSX-3 contained a low level (4

w/o Co). Note that LMSX-1 has 12 wt% Co which is similar to the Co concentration in

Rene N625, and LMSX-3 has 4 wt% Co for comparison to CMSX-10.9 Rene N6 was

developed by GE, and CMSX-10 was developed by Cannon-Muskegon. These

manufacturers have different ideas as to the effects of Co.9'25'31 LMSX-4 and -5 have









variations in the amount of chromium present in these alloys. These alloys were

developed to examine the effect of Cr content on microstructure stability, y' solvus

temperature, and surface stability. LMSX-4 has a high Cr level (6.15 w/o) and LMSX-5

contains a low level (2.1 w/o) of Cr. LMSX-6 has a high level of tungsten (8.6 w/o) to

investigate tungsten's effect on stability and solid solution strengthening. LMSX-7 and -

8 both have a 1 a/o (1.6 w/o) addition of molybdenum, to determine the effect of Mo

additions on stability and solid solution strengthening. LMSX-7 substituted 1 atomic

percent (at%) Mo for 1 at% W, so the alloy contained a reduced amount of tungsten (3.1

w/o). LMSX-9, -10, and -11 all have varying amounts of rhenium. LMSX-9 contains no

rhenium (0 w/o). LMSX-10 contains a low level of rhenium (1 at% or 2.95 wt%).

LMSX-11 has the largest amount of rhenium of all the alloys (3at% or 8.7 w/o). These

alloys are intended to cover what is essentially the first three generations of superalloy

(LMSX-9, -10, and -1) to determine the effect of the Re on stability of first, second, and

third generation superalloys. The high Re content in LMSX-11 was added to investigate

the stability of alloys with large Re additions. In LMSX-12, -13, -14, and -15, the

amounts of the y' former, Al and Ta, were varied from alloy to alloy and titanium was

substituted in the latter two. LMSX-12 and -13 have changes in the amounts of Ta and

Al to determine the effect of Ta/Al ratio variations on solvus and solidus temperatures,

elemental solidification segregation, and y' size and shape. In LMSX-14 and -15, Ti was

substituted for Ta (in LMSX-14) or Al (LMSX-15) to determine if Ti affected the alloys

solidus, solvus, segregation, and strength. The alloys LMSX-12, -13, -14, and -15 were

all intended to have a constant y' volume fraction. To begin examination of the fourth

generation superalloys, LMSX-16 and -17 both have additions of ruthenium (1.6 and 3.2









w/o respectively). It has been reported that Ru additions affect stability and solid

solution strengthening28 and these two alloy were added to investigate that claim.

LMSX-18 has a 1 a/o addition of palladium (1.7 w/o). Pd, a member of the precious

metal group (i.e. Re, Ru, Pd, Pt, Au) was also included in this study since it has also been

reported to affect microstructural stability, strength, and surface stability.32'33

The alloys were cast in single crystal bars at Precision Cast Components Airfoils

(PCC Airfoils, Minerva, OH). A commercial directional solidification furnace was used

with high gradient investment casting techniques to cast the alloys in a [001] orientation.

An inchworm type grain selector was used to produce single crystal samples. The

withdrawal rate was initially set at 6 in (15.24 cm) per hour until the grain selector was

reached. After that point, the rate was changed to 8 in (20.32 cm) per hour. The bars

were cast in cylinders with a diameter of 1.25 cm and a length of 20 cm. One mold was

processed for each alloy, and each mold contained nineteen bars. After casting, the [001]

orientation was verified by Laue backscattered x-ray techniques. For the purpose of this

investigation, samples with defects such as freckles, slivers, high angle boundaries

(HAB), and low angle boundaries (LAB) were not used.

3.2. Metallography

After receipt of the bars, specimens were sectioned for metallographic evaluation.

A LECO CM-20 cut-off wheel, using a LECO 3025 blade (rated for HRC 45-60) was

used to perform all sectioning of the bars. The bar was cut in the middle, and starting

from the cut mid-section ends, another cut was made to leave behind a small disk 1.25 cm

in diameter and z 0.5 cm thick. This disk was then sectioned in half to produce two

semi-circular specimens for microstructural characterization.












Table 3-1:


Compositions of the 18 model alloys in weight percent (wt%). Highlighted regions indicate changes made from baseline.
Com positions ofRene N6 and CMSX-10 sao n


.V l..ll.1r L II Jll V.I I\.'IIU UllV ^II T.1VI*IUI IV LI VV s .l.t U.~llrU I JJll..
Alloy ID Ni Cr Co Mo W Ta Re Al Ti Hf Ru Pd Comments
LMSX-1 Bal 4.10 12.20 5.85 8.60 5.90 5.55 0.10 Baseline
61.95 5.00 13.00 2.00 3.00 2.00 13.00 0.05 Atomic % Composition
LMSX-2 Bal 4.10 8.00 5.85 8.60 5.90 5.55 0.10 Reduced Co (8 at%)
LMSX-3 Bal 4.10 4.00 5.85 8.60 5.90 5.55 0.10 Minimum Co (4 at%)
LMSX-4 Bal 6.15 12.20 5.85 8.60 5.90 5.55 0.10 High Cr (7 at%)
LMSX-5 Bal 2.10 12.20 5.85 8.60 5.90 5.55 0.10 Low Cr (3 at%)
LMSX-6 Bal 4.10 12.20 8.60 8.60 5.90 5.55 0.10 High W (3 at%)
LMSX-7 Bal 4.10 12.20 1.60 3.10 8.60 5.90 5.55 0.10 Low W (1 at%) + 1 at%
Mo
LMSX-8 Bal 4.10 12.20 1.60 5.85 8.60 5.90 5.55 0.10 +1 at% Mo
LMSX-9 Bal 4.10 12.20 5.85 8.60 0.00 5.55 0.10 0 at% Re
LMSX-10 Bal 4.10 12.20 5.85 8.60 2.95 5.55 0.10 1 at% Re
LMSX-11 Bal 4.10 12.20 5.85 8.60 8.70 5.55 0.10 3 at% Re
LMSX-12 Bal 4.10 12.20 5.85 11.20 5.90 5.00 0.10 High Ta
(4at%), Low Al (12 at%)
LMSX-13 Bal 4.10 12.20 5.85 6.00 5.90 6.15 0.10 Low Ta
(2 at%), High Al (14 at%)
LMSX-14 Bal 4.10 12.20 5.85 6.00 5.90 5.65 0.80 0.10 Low Ta
(2 at%) + lat %Ti
LMSX-15 Bal 4.10 12.20 5.85 8.60 5.90 5.10 0.80 0.10 Low Al
(12 at%) + 1 at% Ti
LMSX-16 Bal 4.10 12.20 5.85 8.60 5.90 5.55 0.10 1.60 +1 at% Ru
LMSX-17 Bal 4.10 12.20 5.85 8.60 5.90 5.55 0.10 3.20 +2 at% Ru
LMSX-18 Bal 4.10 12.20 5.85 8.60 5.90 5.55 0.10 1.70 +1 at% Pd
CMSX-10 Bal 3.00 4.00 0.60 6.00 8.00 6.00 5.75 0.10
Rene N6 Bal 4.50 12.50 1.10 5.75 7.50 6.00 5.35 0.15









Once the specimens were cut, they were mounted using a LECO PR-10 mounting press.

The specimens were mounted in 3.175 cm (1.25 inch) mounts using diallyl phthalate and

labeled as LMSX-X as cast, where X indicated the specific alloy identification number.

With the metallographic specimens mounted, they were then leveled, ground, and

polished to a mirror-like finish. The leveling of the specimens was done using a LECO

BG-20 belt grinder with a water cooled 240 grit belt. The edges of the specimen mounts

were first chamfered to ease handling and lessen hydroplaning during polishing.

Leveling was done until there was no diallyl phthalate covering the specimen and there

were no raised spots obvious on the sample.

All of the grinding and polishing was done using a LECO VP-20 Vari/Pol, operated

at z 300 rpm, and water was used to lubricate and cool the specimen. Standard

metallographic practices for grinding and polishing were used to prepare the specimen33

and a Branson 1200 ultrasonic sink was used for ultrasonic cleaning of the specimens

between polishing steps.

Two techniques were evaluated for grinding and polishing. The first technique was

considered the "standard" technique, which has been typically used by the University of

Florida Materials Science and Engineering Department, and the second was an advanced

technique initially developed by Struers Inc and further modified for this study.

The "standard" technique was done on LMSX-1, -2, -3, -4, -5, -9, -10, -11, -16, -17,

and -18. Grinding was done using wet-dry alumina grinding disks beginning with 240

grit, followed with 320, 400, 600, and finally 800 grit. This was followed with two rough

polishing steps. Rough polishing was done using 20.32 cm (8 in) billiard cloths with first

15 |tm and then 5 |tm alumina suspended in water. Fine polishing was done using LECO









Micron cloths with first 1 |tm and then 0.3 |tm alumina suspended in water. All

specimens were polished to a mirror-like finish and examined optically for scratches.

The advanced technique was done on LMSX-6, -7, -8, -12, -13, -14, and -15. The

grinding steps were done using Struers MD-Piano 600 and MD-Piano 1200 grit magnetic

grinding disks. The particulate was imbedded into the disk itself and only needed to be

dressed between specimens to maintain the proper grit size. Rough polishing was done

using a Struers MD-Mol magnetic disk with the appropriate MD-mol solution. This

solution was water based and needed either little or no extra water for lubrication. The

final polishing was done in the same manner as the standard technique. Again, all

specimens were polished to a mirror-like finish and examined optically for scratches.

Although no specimen was done using both techniques, the final requirement was

the same: a mirror-like finish without scratches. This was easily attainable with both

techniques given sufficient time. The advanced technique, using the magnetic disks,

offered reduced grinding and polishing times, less mess, fewer steps, and a decreased

chance of cross contamination between grit sizes. The advanced technique has the

setback of increased time if a step is not done properly due to the large changes in grit

sizes used. If done correctly, specimen preparation time was reduced from 45 min to

20 min.

3.3. Scanning Electron Microscopy/Backscatter Electron Microscopy

Electron microscopy was first done using a JOEL SEM 6400. The instrument was

operated with an accelerating voltage of 15 keV and a working distance of 15 mm. The

instrument was primarily operated in the backscattered mode. Using the backscattered

electron (BSE) imaging, 20 images were taken of each specimen in the as-cast condition.









The images were taken in a grid like manner of four-by-five. The images were 1 mm

apart in the "y" direction and 2 mm apart in the "x" direction. These images were taken

to calculate the primary dendrite arm spacing (PDAS). Figures 3-1 and 3-2 are

representative of the BSE images taken to determine the PDAS. Appendix A contains

additional images from this portion of this investigation.











X






Figure 3-1: BSE image of LMSX-1 taken at 100x equivalent.










Y

X 3






Figure 3-2: BSE image of LMSX-13 taken at 100x equivalent









3.3.1. Electron Microprobe Analysis

The remainder of this investigation of the segregation behavior of these alloys was

done using electron microprobe analysis (EMPA). The instrument used for this

examination was a JOEL 733 Superprobe. The instrument was operated with an

accelerating voltage was 15 keV, a take-off angle of 400, a spot size of 1 tm and a

beam current 20 nA. Each point in the EMPA was measured by wavelength dispersive

spectroscopy (WDS) and measured for 10 seconds per point.

Specific calibration for Ni, Cr, Co, Mo, W, Re, Ta, Al, Ti, Ru, Pd, and Hf were all

used as references. To expedited the scanning times, as many different crystals as

possible were used while maintaining the best line (Kc, Lc, or Mc) to scan. A LiF

crystal was used to measure intensities for Ni, Cr, and Co. The compositional analysis

for these elements was based on the Kc lines. To measure intensities for W, Re, Ta, Hf,

and Al, a TAP crystal was used. To determine the chemical analysis of these elements,

the Kc line for Al was measured, and the La lines were used for all the others on this

crystal. Finally, a PET crystal was used to measure intensities for Ru, Mo, and Ti, with

chemical composition based on the Kc line for Ti and the La lines for Ru and Mo.

A small computer routine for the microprobe had to be used to perform the line

scans, along with some of the proper settings. Due to the age of the equipment, some of

the line scan routines had to be varied to detect specific elements. These routines are

found in Appendix B.

A problem occurred with measuring some of the trace elements due to the age of

the software. The trace elements of Mo in LMSX-7 and -8, Ti in LMSX -14 and -15, and









the Ru in LMSX-16 all required a specific step to be added to this routine to properly

measure the peak.

Line scans were used to measure composition and segregation within the

microstructure. A line of 30 points was scanned running between two dendrite cores

through the interdendritic region. Care was taken to avoid any secondary and tertiary

dendrite arms. Image 3-3 contains an example of one of the line scans examined. The

typical length of each line scan was z 300 |tm. Three scans were done on each specimen

and all the data was entered by hand, again due to the age of the equipment. A total of 90

points were scanned for each specimen. This technique is a variation of that used by

Pollock et. al.34

The technique to measure/quantify solidification segregation was developed by M.

N. Gungor36 and is commonly found to be the industry standard. This technique involves

a grid of point scans across the specimen, all equally spaced. To check the validity of the

new method of using line scans, the grid method was used on LMSX-3. The PDAS of


Figure 3-3: BSE photo of LMSX-1 taken at 100x equivalent. Yellow line indicates
location of the line scan preformed.









LMSX-3 was measured at 253.4 |tm and a slightly larger spacing of 265.0 |tm was used

for the spacings between points in the line scans. Fifteen line scans of fifteen points were

used with the larger spacings used for a total of 225 points scanned.ll This atomic

percent and normalized weight percent data were then entered into a spreadsheet by hand

for analysis.

3.3.2. Verification of Applicability of Analysis

To provide an independent check of this investigation, a piece of as-cast CMSX-4

was sectioned, mounted, and polished (using the standard technique) to an optically

verified mirror like finish. CMXS-4 was used due to availability of the as-cast sample.

The composition of CMXS-4 is listed in Table 3-2. The EMPA was preformed in a

similar fashion to that described above to see if the techniques described above were

applicable to current production alloys and to broaden the possible spectrum of further

understanding of trends found in this experiment.


Table 3-2: Composition of CMSX-4 in wt%.4,6
Alloy ID Ni Cr Co Mo W Ta Re Al Ti Hf
CMXS-4 Bal 6.5 9.0 0.6 6.0 6.5 3.0 5.6 1.0 0.10















CHAPTER 4
EXPERIMENTAL RESULTS

For clarity, the results of this investigation are broken down into three parts. First,

the primary dendrite arm spacing (PDAS) will be discussed. Then the observations of the

electron microprobe analysis are evaluated. Finally, the two electron microprobe analysis

techniques will be compared and evaluative.

4.1. Primary Dendrite Arm Spacing

Twenty 100x images (or fields of view) taken of each of the 18 model alloys were

used to calculate the primary dendrite arm spacing (PDAS). Due to the natural

variabilities in dendrite arm spacings, from 6 to 8 measurements were taken from each

field of view, but the number was held consistent for all fields for that alloy. Figure 4-1

is one of the 100x BSE images from LMSX-12. The black lines drawn on the image are

examples of the lines used to measure the PDAS. This procedure was repeated for all

twenty fields of view, and then the final values were tabulated. To make measuring

easier, the micron bar on the image was measured and used as a standard. It was

measured at 5.4 cm and indicated 500 |tm long. This allowed a machinist's scale to be

used to make all the measurements directly from the field of view and then ratioed back

to the actual size. The average, standard deviation, and median values were all

calculated. Table 4-1 contains the results from these calculations. This was done to

develop an understanding of the accuracy in calculating the PDAS from the EMPA line

scans.









All of the measured PDAS standard deviations were relatively large, and all but

two of the PDAS measurements fell to within one standard deviation of the mean. The

exceptions were LMSX-10 and -17. Of the remaining sixteen alloys, six of the measured

PDAS were very close (about 20 |tm difference) to those calculated from the line scans.

Another eight of the measurements were within about 50 |tm of one another. The only

alloys that exhibited a variation in PDAS greater than 70 |tm (other than LMSX-10 and-

17) were LMSX-1 and -2. LMSX-1 had the highest standard deviation for PDAS of the

eighteen alloys.



















Figure 4-1: BSE image of LMSX-13. Black lines added to image were where PDAS
measurements were taken.

4.2. Electron Microprobe Analysis

To quantify and characterize the inhomogeneties and segregation in the

microstructure that occur during solidification, a lengthy analysis was preformed to

develop a better understanding of the elemental interactions and solidification behavior.

The electron microprobe analysis (EMPA) results are broken down into three sections.

The first section contains the results of the line scan technique and how they relate to the









Table 4-1: PDAS measurements from EMPA and from hand calculations. Standard
deviation is shown for hand calculations. All measurements are in |tm.
LMSX- 1 2 3 4 5 6 7 8 9
EMPA 287.66 267.39 250.94 259.61 262.91 225.52 307.24 262.31 367.90
Measured 374.33 343.00 253.47 294.35 310.84 281.65 331.78 320.62 381.86
St Dev 104.1 98.7 64.3 84.0 87.1 97.5 80.7 74.1 84.5

LMSX- 10 11 12 13 14 15 16 17 18
EMPA 271.41 223.59 275.72 257.35 226.80 290.93 247.51 174.70 258.09
Measured 360.23 258.52 325.85 280.03 281.48 286.40 284.51 268.91 271.53
StDev 116.1 61.0 79.5 79.8 72.4 78.2 61.7 79.9 70.1
elemental segregation and partitioning for the eighteen model alloys. The next section

contains the results from the grid scan of LMSX-3. Finally, the data from the line scans

from CMSX-4 are presented. The data was measured in atomic percent (at%) and then

converted to normalized weight percent (wtO) and recorded.

Within these eighteen model alloys, a total of fifteen relationships were observed.

Eight of these relationships could be directly related to the variation of a single elemental

addition. The remaining seven show the interactions that appear to be present from alloy

to alloy based on the variation of only two elements (i.e. Ta and Al both varied from

baseline). The relationships observed that relate to elemental variations are as follows:

* Cobalt. By comparing LMSX-1, -2, and -3.
* Chromium. By comparing LMSX-1, -5, and -5.
* Rhenium. By comparing LMSX-1, -9, -10, and -11.
* Ruthenium. By comparing LMSX-1, -16, and -17.
* Tungsten. By comparing LMSX-1 and 6.
* Molybdenum. By comparing LMSX-1 and -8
* Palladium. By comparing LMSX-1 and -18.
* Tungsten with a Molybdenum addition. By comparing LMSX-7 and -8.

The remaining relationships that were observed were examined to qualify the interactions

that might be present in the systems where two elemental additions were varied. These

systems are listed as follows:









* Variation of Tantalum and Aluminum from the baseline. LMSX-1, -12, and
LMSX-1, -13.

* Variation between Tantalum and Aluminum. LMSX-12 and -13.

* Variation of Tantalum and Aluminum from the baseline with an addition of
Titanium. LMSX-1, -14, and LMSX-1, -15.

* Variation between Tantalum and Aluminum with an addition of Titanium. LMSX-
14 and -15.

* Variation between decreasing Tungsten and increasing Molybdenum. LMSX-1, -7
and -6, -8.

As noted previously, all final data from the line scans is presented in normalized

weight percent (wt%).

4.3. Elemental Segregation and Partitioning

Three line scans from dendrite core to dendrite core through the interdendritic

region were preformed on one specimen from each of the model alloys. The composition

of each point along the line in each alloy was determined. The average values for each

element for the three line scans for each specimen were calculated. Appendix C contains

the average EMPA results for the eighteen model alloys. Nearly all the elements in all

the alloys exhibit some degree of segregation; however the degree and direction

dendriticc or interdendritic) of the segregation varied. A partitioning coefficient (k') was

calculated from the average values of each element from the set of line scans from each

alloy

The partitioning coefficient parameter is indicative of the degree of segregation

during solidification and tendency for an element to segregate to either the dendrite core

or the interdendritic region and how much upon casting. k' is defined as


k'= XDendrite (Equation 1-1)
i,Interdendrtec









where xi, dendrite is the composition (in wt%) at the dendrite core and xi, interdendritic is the

composition (in wt%/) roughly equidistant between both dendrite cores.11 16,36-40 The

points chosen for the determination of the segregation partition coefficient came from

either end of the line scan (i.e. the dendrite core). The interdendritic value was chosen

from either of the midpoint of this average scan, with one exception. When the minimum

or maximum compositional level did not occur at the midpoint, this interdendritic value

was taken from a trendline. If the mid points did not lie reasonably near the trendline, the

next point on the line was chosen. This was done to avoid the possibility that the mid-

points chosen would not indicate the actual degree of segregation as shown by the

trendlines of the actual data was as indicated. Table 4-2 contains the k' values calculated

from this method. Data listed as k'A is the data collected by F. Fela.16 The partitioning

coefficients calculated in this study are reported as k'B.

A k' less the unity indicates a tendency of this element to segregate to the

interdendritic region; whereas a k' greater than unity indicates segregation to the dendrite

core.11,16,36-38 Graphs were then developed to show the variations of k' as the

composition was varied in this investigation. Figures 4-2, 4-3, and 4-4 graphically

illustrates how k'A and k'B compared to one another for LMSX-1, -13, and -18 as

examples.

From the comparisons, it can be seen that although the segregation behavior in both

studies indicate similar directions of segregation, the magnitudes varied particularly for

Re. The magnitude difference can be attributed to differences in the location used to

measure composition within the specimen being locally different from one another.

However, it is clear that the segregation trends represented by k' largely holds true for









both k'A and k'B. The y' former, Ni, Al, Ta, and Ti, all segregated to the interdendritic

region, and the y solid solution strengtheners, Cr, Co, W, and Re segregated to the

dendritic region. Although the segregation behavior was similar in both studies, there

was a discrepancy in the segregation behavior of Mo in LMSX-8 (+ 1 at% Mo). k'A

indicated that Mo segregated to the dendritic region, whereas k'B indicated Mo

segregated to the interdendritic region. Figure 4-5 contains the graph that compares the

results of both k'A and k'B. Figure 4-6 is the graph for LMSX-8 that was used to identify

the points for the k' partitioning analysis. The points chosen for the k' analysis are

shown as large open circles on the graphs. In addition, a second order trend line was

plotted to aid in visualizing the segregation behavior. For comparison, a similar graph for

Al from LMSX-1 and -18 is shown with the same data points used for calculation of k'

labeled as in Figure 4-7.












Table 4-2


Showing weight percentages of each respective element in each alloy from the dendrite core and the interdendritic region,
na d the calculated k' value for both te )


Alloy Ni Cr Co Mo W Re Ta Al Ti Ru Pd
Dendritic 56.04 4.07 13.04 6.83 10.49 4.86 4.33
Interdendritic 61.76 3.93 11.40 4.31 3.38 10.08 5.74
LMSX-1
k'B 0.91 1.04 1.14 1.58 3.10 0.48 0.75

Dendritic 59.96 4.27 9.04 6.73 10.85 5.02 4.67
Interdendritic 63.85 3.56 7.64 4.29 3.57 10.38 6.39
LMSX-2
k'B 0.94 1.20 1.18 1.57 3.04 0.48 0.73

Dendritic 64.90 3.91 4.33 6.71 10.79 4.98 4.46
Interdendritic 69.00 3.66 3.52 3.58 2.22 11.35 6.33
LMSX-3
k'B 0.94 1.07 1.23 1.87 4.86 0.44 0.70

Dendritic 54.87 6.35 13.37 6.67 9.72 4.26 4.46
Interdendritic 59.16 6.07 11.19 4.38 3.16 9.29 5.48
LMSX-4
k'B 0.93 1.05 1.19 1.52 3.08 0.46 0.81

Dendritic 60.75 2.59 13.37 5.79 9.29 3.69 4.51
Interdendritic 64.88 2.65 12.87 3.54 3.59 6.86 5.79
LMSX-5
k'B 0.94 0.98 1.04 1.64 2.59 0.54 0.78

Dendritic 57.17 4.67 13.97 8.44 9.17 3.43 4.56
LMS6 Interdendritic 61.76 4.54 12.01 4.47 3.41 8.46 6.61
k'B 0.926 1.029 1.163 1.888 2.689 0.405 0.690












Table 4-2 (Cont.) showing weight percentages of each respective element in each alloy from the dendrite core and the interdendritic
region, and the calculated k' value A (in blue), and B (in orange).
Alloy Ni Cr Co Mo W Re Ta Al Ti Ru Pd
Dendritic 60.3 4.74 13.65 1.61 2.88 8.64 3.97 4.72
LMSX- Interdendritic 62.48 4.29 12.89 1.82 2.04 3.67 7.37 5.65
7 k'B 0.97 1.10 1.06 0.88 1.41 2.35 0.54 0.84

Dendritic 57.75 4.44 13.71 1.54 5.55 8.59 3.91 4.71
LMSX- Interdendritic 61.5 4.3 12.97 1.88 3.81 3.47 7.75 5.56
8 k'B 0.94 1.03 1.06 0.82 1.46 2.48 0.50 0.85

Dendritic 64.35 3.79 12.82 7.39 0 5.62 4.70
LMSX- Interdendritic 63.79 3.79 11.59 4.57 0 9.25 5.45
9 k'B 1.01 1.00 1.11 1.62 0.00 0.61 0.86

Dendritic 60.31 3.83 13.53 6.91 5.69 5.32 4.60
LMSX- Interdendritic 62.62 3.59 11.38 4.32 1.67 10.65 5.53
10 k'B 0.96 1.07 1.19 1.60 3.41 0.50 0.83

Dendritic 54.30 4.63 13.62 4.82 13.81 3.29 4.40
LMSX- Interdendritic 62.62 3.61 10.92 2.79 2.06 9.79 6.80
11 k'B 0.87 1.28 1.25 1.73 6.70 0.34 0.65

Dendritic 57.53 4.41 13.89 5.97 8.85 5.26 4.36
LMSX- Interdendritic 61.26 3.90 12.03 3.80 3.31 9.76 5.68
12 k'B 0.94 1.13 1.15 1.57 2.67 0.54 0.77












Table 4-2(Cont.) showing weight percentages of each respective element in each alloy from the dendrite core and the interdendritic
region, and the calculated k' value A (in blue), and B (in orange).
Alloy Ni Cr Co Mo W Re Ta Al Ti Ru Pd
Dendritic 59.49 4.14 13.36 5.69 9.97 2.18 5.07
LMS Interdendritic 67.13 4.63 11.14 2.75 1.70 6.42 7.37
LMSX-13
k'B 0.89 0.89 1.20 2.07 5.86 0.34 0.69

Dendritic 61.75 4.72 13.97 5.25 7.30 1.93 4.12 0.48
Interdendritic 66.52 3.96 12.66 2.87 2.34 4.38 5.70 1.15
LMSX-14
k'B 0.93 1.19 1.10 1.83 3.12 0.44 0.72 0.42

Dendritic 58.23 4.32 13.82 5.72 9.66 3.58 4.19 0.42
Interdendritic 63.99 3.78 11.32 2.99 2.40 8.04 5.94 1.13
LMSX-15
k'B 0.91 1.14 1.22 1.91 4.03 0.45 0.71 0.37

Dendritic 57.37 4.52 14.51 5.11 9.35 3.55 4.59 1.63
Interdendritic 61.41 4.04 12.17 3.36 3.16 7.53 4.52 1.38
LMSX-16
k'B 0.93 1.12 1.19 1.52 2.96 0.47 1.02 1.18

Dendritic 55.41 4.24 13.69 5.77 9.66 3.52 4.52 3.59
Interdendritic 61.49 3.68 10.97 3.10 1.68 10.11 6.34 3.11
LMSX-17
k'B 0.90 1.15 1.25 1.86 5.75 0.35 0.71 1.15

Dendritic 57.23 4.13 13.86 6.06 10.12 3.84 4.41 0.80
LMS 8 Interdendritic 61.84 3.71 11.22 2.91 2.23 8.74 6.47 2.95
k'B 0.93 1.11 1.24 2.08 4.54 0.44 0.68 0.27









With k'B exhibiting the same trend as k'A, the composition effects and some of the

elemental interactions were plotted. When examining the effect of elemental variations,

all the compositional effects were compared directly to the baseline alloy LMSX-1. Note

that k'B is calculated using equation 1-1, however the data used in this calculation was

obtained from data collection method described in this paper.

4.3.1. Cobalt Partitioning

The effects of cobalt variations (LMSX-1, -2 and -3; 12.2 wt% Co, 8.0 wt% Co,

and 4.0 wt% Co respectively) on the k'B values were all of the elements in the alloy were

plotted against increasing Co content. From this graph (Figure 4-8), it can be seen that

increasing Co content decreased the segregation of the elements that partition to the

dendrite core. The largest decrease in segregation occurs with Re followed by W, Co

itself, and finally Cr. The effect on Cr is a very small decrease in segregation over the

range of 4 wt% to 12.2 wt% Co. Whereas the effect of Re decreased markedly as the Co

level is increased to the 8 wt% Co, and then remains constant with further increasing Co.

It should be noted that the increase in Co content in these alloys results in a decreased

segregation of Co itself, but only slightly.

When looking at the elements that segregate to the interdendritic region (Figure 4-

9), increasing the Co content also decreased the segregation of Al and Ta, but slightly

increased the segregation of Ni. The decrease in partitioning for Al with increasing Co

content greater than that for Ta, but the Ta follows the same trend as Re does in that the

degree of segregation is decreased to the 8 wt% Co point and then becomes essentially

constant. As was stated, the segregation of Ni increased with increasing Co, but Ni is the

only element that was observed to exhibit increased segregation when increasing Co

content.









4.3.2. Chromium Partitioning

The alloys with varying chromium content were the second group examined. This

series of alloys consists of LMSX -5, -1, and -4 (2.1 wt% Cr (3 at%), 4.1 wt% Cr (5 at%),

and 6.15 wt% Cr (7 at%) respectively). The effects of this addition on the elements in the

alloy (Ni, Cr, Co, W, Re, Ta, and Al) was examined and characterized. Increasing the Cr

concentration increased the segregation of Re, Co, and Cr. The increase in Re

segregation, being the most consistent and pronounced when compared to that of Co and

Cr. Co partitioning increased as Cr content was increased, and the Cr partitioning did

increase slightly. In the baseline alloy, LMSX-1, and the high Cr content alloy, LMSX-4,

Cr was observed to partition to the dendrite core. But in the low Cr alloy (LMSX-5), Cr

was observed to segregate to the interdendritic region. W had a different response to this

change in concentration; as Cr content increased, the W partitioning decreased. The

partitioning coefficient for Co at the 2.1 wt% Cr was the lowest found in this

investigation indicating that Co partitioned the least in this alloy. Figure 4-10 shows the

effect graphically of increasing Cr concentration on the segregation of elements

partitioning to the dendritic region.








40




k' Comparison for LMSX-1

35




mTechnLque A
hTechnique B
25


2


15








05


NI Cr Co W Re Ta Al

Figure 4-2: k' values for LMSX-1 for techniques A (orange) and B (blue). The green
line is at k' = 1.


k' Comparison for LMSX-13



mTechnlque A
mTechnlque B







4


3


2







NI Cr Co W Re Ta Al

Figure 4-3: k' values for LMSX-13 for techniques A (orange) and B (blue). The green
line is at k' = 1








41




k' Comparison for LMSX-18


ETechnique A
ETechnique B


Ni Cr Co W Re


Figure 4-4: k' values for LMSX-
line is at k' = 1.





600

ETechnique A
ETechnique B
5 00



400



S3 00
Differel


200



1 00



0 00


Ta Al Pd


18 for techniques A (orange) and B (blue). The green


k' Comparison for LMSX-8


Ni Cr Co Mo W Re


Figure 4-5: k' values for LMSX-8 for techniques A (orange) and B (blue). The green

line is at k' = 1. The difference is noted by a circle.








42




Plot of Molybdenum Segregation in LMSX-7 and -8
with Normalized PDAS
250 -




200

-U-." -- .- _--__.
==
150
0



1 00

LMSX-7
LMSX-8
PLMSX-8

0 -5




00
0 02 04 06 08 1
Normalized PDAS

Figure 4-6: Mo segregation plot for LMSX-7 and -8. White points were used in k'B

analysis. Second order trendlines are also shown for both alloys.


Plot of Aluminum Segregation in LMSX-1 and -18
with Normalized PDAS
700
0
650


600
650 //---------------- ------------------







3 50
O / \ 41














300
0 02 04 06 08
Normalized PDAS

Figure 4-7: Al segregation plot for LMSX-1 and -18 shown for comparison. White

points were used in k'B analysis. Second order trendlines are also shown for

all alloys.









The effect of increasing Cr on elements that partition to the interdendritic region is

shown in Figure 4-9. The partitioning behavior of Ni, Al, and Ta due to varying the Cr

concentration was not consistent. Ta showed a linear increase in partitioning as the Cr.

The partitioning of Ni did not appear to be affected by the change in Co content. The

graph in Figure 4-11 shows a decrease in the partitioning coefficient, but the variation are

small and may be due to experimental data scatter. The effect of Cr content on the

partitioning of Al was still different than that of Ni and Ta. Al partitioning decreased as

Cr content increased.

4.3.3. Rhenium Partitioning

Alloys LMSX-9, -10, -1 and -11 were used to evaluate the changes in partitioning

due to increasing Re content. LMSX-9 is a first generation superalloy with 0 wt% Re,

LMSX-10 is a second generation superalloy with 1 at% Re (- 3 wt%), LMSX-1 is the

baseline and is a third generation superalloy with 2 at% Re (- 6 wt%), and LMSX-11 is a

model alloy with 3 at% Re (z 9 wt%) and was added to examine the effect of a large Re

additions on alloy stability. Figure 4-12 contains the k'B curves for elements segregating

to the dendritic region, and Figure 4-13 contains the k'B curve for elements that segregate

to the interdendritic region.

Of the elements segregating to the dendrite cores, Re shows the largest increase in

partitioning due to the increase in Re concentration. The partitioning coefficient for Re

in LMSX-11 (8.95 wt% Re) was the largest k' value observed in this experiment. Cr and

Co also exhibit increasing segregation levels when the Re content was increased up to the

5.95 wt% Re (LMSX-1) concentration. At the highest Re concentration, the Co showed a

slightly greater propensity to partition to the dendrite core.









44





Partitioning Effect with Varying Co


6000




5 000
"-- *--Cr
S----CO

4000




". 3000




2 000

40 --------------------- ----------------


1000 ---



0 00
2 4 6 8 10 12 14
wt% Co


Figure 4-8: Partitioning effects due to increasing Co concentration for elements showing

a preference to segregate to the dendritic region.



Partitioning Effect with Varying Co


1 000

0 0 0 ^ -----------------------------------' ------
0900


0 800


0 700 A------A -- -


0 600


0500


0400


0300


0200


0 100


0000
2 4 6 8 10 12 14
wt% Co


Figure 4-9: Partitioning effects due to increasing Co concentration for elements showing

a preference to segregate to the interdendritic region.















Partitioning Effect with Varying Cr


3500



3 000



2500
-- CO


2 00



1 500



1 000



0 500



0 000
1 2 3 4 5 6
wt% Cr


Figure 4-10: Partitioning effects due to increasing Cr concentration for elements showing

a preference to segregate to the dendritic region.



Partitioning Effect with Varying Cr


1 000


0900


0 800 --
0800 A-..-...----- . .... A

0 700


0 600 -M-Ta


a. 0 500


0 400


0 300


0200


0 100


0000
1 2 3 4 5 6 7
wt% Cr


Figure 4-11: Partitioning effects due to increasing Cr concentration for elements showing

a preference to segregate to the interdendritic region.









The Cr continued to exhibit a limited degree of segregation to the dendritic core, and the

final k'B values for Cr and Co for LMSX-11 (8.9 wt% Re) were virtually the same.

LMSX-11 contained the most severe segregation and, therefore the highest partitioning

coefficients for Cr, Co, and Re for this investigation.

Increased Re contents also resulted in an increasing segregation ofNi, Ta, and Al.

Ta showed the greatest degree of segregation for these three elements, followed by Al,

and then Ni. Ni showed a linear decrease in k'B (increasing segregation) as the Re

concentration was increased. Ta and Al showed somewhat parabolic decreasing trends in

k' as the Re content increased. Unlike in the Re bearing alloys, Ni partitioned to the

dendritic region for LMSX-9 (0 wt% Re). LMSX-11 showed the greatest amount of

partitioning in Ni, Al, and Ta for this investigation. In general, the segregation behavior

of all of the elements was reduced to its lowest levels in the 0 wt% Re (LMSX-9) alloy,

and the highest levels in the 8.9 wt% (LMSX-11) alloy.

4.3.4. Tungsten partitioning

The effects of increasing the W concentration were also evaluated in this

investigation by comparing LMSX-1 (5.85 wt% W) and LMSX-6 (8.9 wt% W). Figures

4-14 and 4-15 show the changes in the partitioning coefficient for the base elements (Ni,

Cr, Co, W, Re, Ta, and Al) as the concentration of W is increased. W had a variety of

effects on the elements that commonly segregate to the dendritic regions (Re, W, Co, and

Cr). The first effect noted was that the increased concentration of W, also resulted in an

increased W partitioning coefficient. This was the only element with k'B greater than one

(i.e. elements that partitioned to the dendrite core) that showed an increase in this

segregation. Co and Cr were unchanged as the W concentration was increased.









Somewhat unexpectedly, the increase in W content resulted in a decrease in the

segregation of Re.

Similar to the varied segregation behavior in the dendritic segregating elements, the

elements segregated to the interdendritic region also showed very different responses.

Raising the W levels in the alloy caused Ta and Al to segregate to a greater extent, with

Ta exhibiting a greater degree of segregation than Al. In a pattern similar to that shown

by Re for this series, the partitioning of Ni decreased (k'B approaching one) with

increasing W content.

4.3.5. Tungsten Partitioning with an Addition of Molybdenum

LMSX-7 and -8 both had a 1 at%/ Mo addition to evaluate the effects of Mo on the

segregation behavior of the alloys. In addition, the W concentration in LMSX-7 was

decreased to 3.1 wt% (1 at%). Re, W, Cr, and Co all segregated to the dendrite core

regions of the as-cast structure (Figure 4-16). As the W concentration was decreased

from 5.85 wt% to 3.1 wt%, Re showed the largest decrease in segregation of the elements

in this alloy. The segregation behavior of W itself was also decrease slightly. The

partitioning behavior of Co was unaffected by the decrease in W concentration. The

degree of Cr segregation increased as the W concentration decreased. Mo, Ni, and Ta all

exhibited a decreased degree of segregation as the W concentration was decreased. The

change in W had no obvious effect on the Al segregation behavior. The lowest k'B

values for W and Re (indicating the least amount of segregation) in this investigation

were found in LMSX-7. Figure 4-17 clearly illustrates the effect of decreasing W

concentration the segregation behavior ofNi, Ta, Mo, and Al.









48




Partitioning Effect with Varying Re


8000


7 000
Cr
-Co
6000 --W


5000


2. 4000


3000


2 000
A 00- ----------------- -----------------t-h----------------A





0 uuuI
0 1 2 3 4 5 6 7 8 9 10
wt% Re


Figure 4-12: Partitioning effects due to increasing Re concentration for elements showing

a preference to segregate to the dendritic region.



Partitioning Effect with Varying Re


1 200 -



1 000 -




0800 -, --4



0 0600



0 400 -



0200





0 1 2 3 4 5 6 7 8 9 10
wt% Re


Figure 4-13: Partitioning effects due to increasing Re concentration for elements showing

a preference to segregate to the interdendritic region.









49





Partitioning Effects with Varying W





35000 '------------ -------------------------


2 500
*- -Cr




d- W
2000 Re
-A





- -- - --*
1 500



1 000 -



0 500



0000
5 55 6 65 7 75 8 85 9 95
wt% W


Figure 4-14: Partitioning effects due to increasing W concentration for element

segregating to the dendritic region.



Partitioning Effects with Varying W


1 000


0 900


0 800


0 700 .


0 600


S0 500 -


0400 -


0 300


0200 -


0 100


0000
5 55 6 65 7 75 8 85 9 95
wt% W


Figure 4-15: Partitioning effects due to increasing W concentration for element

segregating to the interdendritic region.









50




Partitioning Effects with Varying W
(Mo added)


300



250



200



S1 50



1 00


2 25 3 35 4 45
wt% W


5 55 6 65 7


Figure 4-16: Partitioning effects due to decreasing W concentration with the addition of 1

at% Mo for element segregating to the dendritic region.



Partitioning Effect with Varying W (Mo added)


U- -'- -- -


--*-- N i
-- Mo
- -A Ta
-4-0- Al


A ------- - - --. --- .-. .-. -A


000 1
2 25 3 35 4 45 5 55 6 65 7
wt%


Figure 4-17: Partitioning effects due to decreasing W concentration with the addition of 1

at% Mo for element segregating to the interdendritic region.


1 20




1 00




080




, 060




040


020


--M -Co







7 A-- W
i i ------------









4.3.6. Molybdenum Partitioning

By examining the segregation behavior of the baseline (LMSX-1) and LMSX-8

alloys, the effect of a single addition of Mo could be observed. The elemental

segregation behavior of elements that partition to the dendritic regions is shown in

Figure 4-18 and Figure 4-19 illustrates the segregation behavior of elements that partition

to the interdendritic region. The addition of 1 at% Mo decreased the overall segregation

of nearly every element in the alloy. k'Re decreased the most substantially followed by

k'w, and finally k'co. Cr partitioning was virtually unaffected by the addition of Mo to

this alloy.

The elements that exhibited partitioning coefficients (k') less than one, also

exhibited a similar segregation behavior with the addition of 1 at% (1.6 wt%) Mo. The

segregation of Al was observed to decrease to the greatest degree followed by Ni and

finally Ta. Mo was observed to partition to the interdendritic regions, and partitioned

more strongly than Al and less than Ta.

4.3.7. Ruthenium Partitioning

Ruthenium has become an alloying addition of great interest and is currently being

added to the newer superalloys28,39', which are called fourth generation superalloys. To

investigate the effect of Ru, two alloys were included in the alloy design matrix (see

Table 3-1). The first was LMSX-16, which was the baseline LMSX-1 alloy with an

addition of 1 at% Ru (1.6 wt%). The second alloy, LMSX-17, contained 2 at% Ru (3.2

wt%). The addition of 1 at% Ru had no affect on Re segregation. However, when the Ru

content was increased to 2 at%, Re begins to partition more dramatically. The remaining

elements with k'B greater than one (i.e. partition to the dendrite core) all show essentially

linear trends (Figure 4-20) for all three Ru concentrations (LMSX-1 (0 at% Ru), LMSX-









16 (1 at% Ru), and LMSX-17 (2 at% Ru)). Cr segregated to a lesser degree than Re for

all of the alloys in this study, and showed a linear increase in segregation as the Ru

concentration increased. The k'B values for Co and W both increased by a similar

amount with the increase in Ru content. With the increase in Ru, Ru itself showed a

decrease in its segregation behavior. The k'B for Co in LMSX-17 was the largest value

found for Co in this investigation, indicating that Ru strongly influences the segregation

behavior of Co.

Of the elements segregating to the interdendritic region in LMSX-1, -16, and -17,

Ta showed the greatest degree of segregation followed by Al and finally Ni (Figure 4-

21). The segregation of Ta does not change until the Ru content was greater than 1.6

wt% (1 at%). When the Ru concentration was increased above 1 at%, Ta began to

segregate to the interdendritic region more substantially than at lower Ru concentrations.

Al followed a similar pattern to Ta, but not as strongly. It should also be noted that Al

segregation behavior seemed to be reversed in the 1 at%/ Ru alloy since Al was observed

to segregate to the dendritic region in LMSX-16. Ni was the only element that was

relatively unaffected by the addition or Ru, and exhibited only a slight trend towards

increased segregation with the increasing Ru content.

4.3.8. Palladium Partitioning

The effect of Pd, a precious metal group element, was examined using LMSX-18 (1

at% Pd). Of the elements that exhibited tendencies to segregate to the dendrite cores, Re

was affected the most by the Pd addition, and then followed by W (Figure 4-22). Both

Re and W showed increased segregation as Pd was introduced into the alloy. Although

Cr and Co partitioning both increased with the increasing Pd content, it was not to the

extent of the increase observed in W and Re.









53




Partitioning Effect with Varying Mo

3500



3000


2 5 0 0 0--











2 000
31000 .-- .------------------------------














0 000
0 02 04 06 08 1 12 14 16 18
wt% Mo


Figure 4-18: Partitioning effects due to the addition of 1 at% Mo for element segregating

to the dendritic region.



Partitioning Effects with Varying Mo

1 000 -

09004-
0 800 . . . . ..-- '---------- ----
0 800





-HT
0 700

0600 T

0500 --

0 400 Al

0300 -AI

0200

0 100

0000
0 02 04 06 08 1 12 14 16 18
wt% Mo


Figure 4-19: Partitioning effects due to the addition of 1 at% Mo for element segregating

to the interdendritic region.









54




Partitioning Effect with Varying Ru


1 UUU -


0 900


0 800


0 700


0600


0 500 1 2 3


0 400 "
--a

CoAl
0300


0200


0 100




wt% Ru


Figure 4-20: Partitioning effects due to Ru addition for element segregating to the

dendritic region.



Partitioning Effect with Varying Ru











-a- Re
S000


4 000





2000

UUU- -


wt% Ru


Figure 4-21: Partitioning effects due to Ru addition for element segregating to the

interdendritic region.









The presence of Pd in the alloy (LMSX-18) caused a decrease in segregation of Ni

to the interdendritic regions (Figure 4-23). Segregation for Al and Ta both increased due

to the addition of 1.7 wt% (1 at%) Pd, and their increases were similar in magnitude.

From the k'B values calculated, Pd itself segregated heavily to the interdendritic region.

4.3.9. Tungsten and Molybdenum Partitioning Interactions

Although the segregation behaviors of alloys with an increasing W content

(LMSX-1 and -6), with an addition of Mo (LMSX-1 and -8), and with decreasing W

content with an addition of Mo (LMSX-7 and -8) were discussed, the segregation

behavior due to substituting Mo for W was evaluated (LMSX-1 and -7, and LMSX-6 and

-8) for interactions and consistency. These graphs from this evaluation are presented in

See Figure 4-24.

The first alloys compared were between LMSX-1 (5.85 wt% W, 0 Wt% Mo) and

LMSX-7 (3.1 wt% W, 1.6 wt% Mo). The segregation behavior for those elements whose

partitioning coefficient, k'B, value is greater than one are Re, W, Cr, and Co. The

substitution of 1 at% Mo for 1 at% W caused a decrease in the segregations of Re, W,

and Co. The decrease in segregation for Re was the most significant followed by W and

finally Co, which showed only a slight decrease in segregation. Cr segregation increased

slightly due to this alloy modification. All of the elements that segregated to the

interdendritic region exhibited a decrease in partitioning due to the decrease in W content

and the Mo addition. The partitioning of Al was reduced to the greatest degree, followed

by Ni. The degree of segregation observed for Mo was intermediate to Al and Ni, but

since it is only one point no further observation can be made. The segregation of Ta was

also decreased, but not to the extent of Ni.









56




Partitioning Effects due to Pd Addition


1 o00


090


0 80

07 ------------------^ -----










----Ta
0 30 ~A-l


020


0 10

00
0 02 04 06 08 1 12 14 16 18
wt% Pd


Figure 4-22: Partitioning effects due to Pd addition for element segregating to the

dendritic region.



Partitioning Effects due to Pd Addition


500 -


450Co


400


350


3004




200 -- Re


1 50







u uu
0 02 04 06 08 1 12 14 16 18
wt% Pd


Figure 4-23 Partitioning effects due to Pd addition for element segregating to the

interdendritic region.









To verify the trends shown in decreasing W content with an addition of Mo,

LMSX-6 (8.6 wt% W, 0 wt% Mo) and -8 (5.85 wt% W, 1.6 wt% Mo) were compared.

All of the trends noted in the LMSX-1 and -7 comparison were present in the evaluation

of LMSX-6 and -8 (Figure 4-25), but the magnitudes had changed. The segregation

behavior of Re was still observed to decrease with decreasing W content, but at a lower

rate than the alloys with a lower concentration ofW. W exhibited more initial

segregation due to the increased W content of LMSX-6, but decreased to nearly the same

k'B values for both LMSX-7 and -8 indicating an increased segregation at high W

concentrations. Ta and Ni both exhibited greater decreases in segregation behavior when

the W content was reduced from 8.6 to 5.85 wt% and 1.6 wt% Mo was added. However,

Ta and Ni were both initially more segregated in LMSX-6 than LMSX-1. The

segregation behavior of Co was observed to decrease more, but like Ni and Ta, was to a

greater extent segregated in LMSX-6 than LMSX-1. Cr and Al segregation did not

indicate any change due to decreasing W from a high content to an intermediate content

combined with adding Mo. When comparing the degree of segregation in these four

alloys (LMSX-1, -6, -7 and -8), LMSX-8 exhibited the least amount of segregation.

4.3.10. Tantalum and Aluminum Partitioning Interactions

The next group of interactions observed come from those alloys that had varying

amounts of both Ta and Al (LMSX-12 and -13). LMSX-12 is a modified baseline alloy

with 4 at% Ta (11.2 wt%/, termed high Ta) and 12 at% Al (5 wt%, termed low Al).

LMSX-13 contained a reduced Ta content (2 at%, 6 wt% termed low Ta) and an

increased Al concentration (14 at%, 6.15 wt% termed high Al). Comparing the elements

of these alloys to one another as well as the baseline (LMSX-1) was done to characterize







58



Partitioning Interactions due to Decreasing W and a Mo Addition


Alloy (LMSX-X)


Figure 4-24: Partitioning trends for elements in LMSX-1 and-7. Difference in the two
alloys is that LMSX-7 contains 3.1 wt% W and an addition of 1.6 wt% Mo.


Partitioning Interactions Due to Decreased W and a Mo Addition


Alloy (LMSX-X)


Figure 4-25: Partitioning trends for elements in LMSX-6 and -8. Difference in the alloys
is that LMSX-6 contains 8.6 wt% W, 0 wt% Mo, and LMSX-8 contains 5.85
wt% W, 1.6 wt% Mo.









the interactions. Recall that all of these alloys have similar volume fractions ofy', so the

alloy modifications are only intended to alter the composition of the phases.

The increase in Ta to 11.2 wt% coupled with a decrease in Al to 5 wt% (LMSX-1

to LMSX-12) resulted in a variety of effects on the elements in the alloys (Figure 4-26).

Increased Ta and decreased Al contents caused a decrease in the segregation of Re, but

Re remained the most segregated element present in this alloy. Ta showed the second

greatest decrease in segregation which is surprising since the amount of Ta was increased

by 1 at% (z 3 wt%). The only other element that showed some effect due to this change

was Cr, whose partitioning increased. The other elements in the system, W, Co, Ni, and

Al did not show any significant change in segregation due to the modification in alloy

chemistry.

To continue to evaluate the role of the y' former, another combination of alloys

was used to begin to examine partitioning interactions (LMSX-1 and -13). The

difference in chemistry for these two lies in LMSX-13 which contains a reduced quantity

of Ta (from 8.9 wt% down to 6 wt%) and an increase in Al (from 5.55 wt% up to 6.15

wt%). The overall trend for this alloy modification was an increase in segregation for all

elements except for Cr which began to segregate to the interdendritic region. The largest

increase in segregation of the elements that exhibited dendritic segregation, was in the

segregation for Re, which nearly doubled. The next greatest increase in segregation was

observed in W. Co was the only element that did not appear to be affected by the change

in alloy chemistry (Figure 4-28). Ta also exhibited a significant increase in segregation of

those elements that had a k'B less than one. However, the segregation of Ta was

significantly lower in magnitude in comparison to Re. Al segregation also increased to a









lesser extent than Ta. Ni exhibited a slight increase in partitioning due to this change in

chemistry (Figure 4-29).

LMSX-12 was also compared directly to LMSX-13 to further characterize these

alloy modification effects (Figures 4-30 and 4-31). Not surprisingly, the trends reported

for the LMSX-1 to LMSX-13 interactions were to be observed when examining LMSX-

12 and LMSX-13. Re segregation increased again, and by a factor of more than two. W

segregation also increased, but not to the degree of Re. Again, Co partitioning appeared

unaffected by these alloy modifications. The segregation to the interdendritic region

increased to the largest degree for Ta. Al segregation did increase, but not to the extent

of Ta, and the degree of Ni increased the least.

4.3.11. Tantalum and Aluminum Partitioning Interactions with an Addition of
Titanium

Ta and Al are not the only y' former in Ni-base superalloys. Ti is also

considered to be a y' former. The baseline alloy, LMSX-1, was modified again with Ti

additions for either Ta or Al, to continue to look at the effects of the y' former.

LMSX-14 is LMSX-1 with an addition of 0.80 wt% (1 at%) Ti and a decrease in

Ta from 8.9 wt% (3 at%) down to 6.0 wt% (2 at%) This change in alloy chemistry

changed the segregation of W and Cr causing them both to segregate more to the dendrite

core, with W segregating more strongly than Cr. Re and Co segregation patterns had no

observable change in this comparison (Figure 31). Ta and Al both showed about the

same increase in partitioning to the interdendritic region from the baseline to this

modified chemistry. Ti itself exhibited the strongest segregation to the interdendritic

region. The partitioning behavior of Ni decreased slightly due to these alloy

modifications (Figure 32).








61




Partitioning Interactions Due to Increasing Ta and Decreasing Al


Alloy (LMSX-X)


Figure 4-26: Partitioning trends for elements between in LMSX-1 and-12. Difference in
the two alloys is that LMSX-12 contains 11.2 wt% Ta and 5.0 wt% Al.


Partitioning Interactions Due to Decreasing Ta and Increasing Al

700


6 00


500


4 00


300


200


100


000
1 13
Alloy (LMSX-X)

Figure 4-27: Partitioning trends for elements between in LMSX-1 and-13. Elements
segregating to the dendritic region shown. Difference in the two alloys is that
LMSX-13 contains 6.00 wt% Ta and 6.15 wt% Al.








62




Partitioning Interactions due to Decreasing Ta and Increasing Al













- I


1 00

090

080

070

060

." 050

040

030

020

0 10

000


Alloy (LMSX-X)

Figure 4-28: Partitioning trends for elements between in LMSX-1 and-13. Elements
segregating to the interdendritic region shown. Difference in the two alloys is
that LMSX-13 contains 6.00 wt% Ta and 6.15 wt% Al.


Partitioning Interactions due to Variations in Ta and Al


12 13
Alloy (LMSX-X)


Figure 4-29: Partitioning trends for elements between in LMSX-12 and-13. Elements
segregating to the dendritic region shown.







63



Partitioning Interactions due to Varying Ta and Al

1 00

090

080



060

". 050

040

030

020

0 10

000
12 13
Alloy (LMSX-X)

Figure 4-30: Partitioning trends for elements between in LMSX-12 and-13. Elements
segregating to the interdendritic region shown.

The effect of substituting Ti for Al was evaluated with LMSX-1 and -15, in which


the y' former were again modified (Figure 33 and 34). LMSX-15 is a variant of LMSX-


14 in that it contains the same addition of 1 at% (0.80 wt%) Ti, but LMSX-15 also had a


reduction in Al from 5.10 wt% (13 at%) Al down to 5.0 wt% (12 at%). Of elements


segregating to the dendrite, Re again showed the largest increase in segregation due to the


alloy modification, followed by W. Cr segregation also increased, but only slightly, and


Co showed even less of a change than Cr due to this alloy modification. Ta and Al both


showed the same degree of increase in segregation with the substitution of Ti for Al. Ni


appeared to be unaffected by this modification in alloy chemistry. Ti itself again


segregated to the interdendritic region, more strongly than any other element.


Using the combination of LMSX-14 and LMSX-15, it is now possible to observe


the interactions between Ta and Al with the Ti addition being constant. When









comparing, LMSX-14 and -15, Re showed a large increase in segregation due to the

increased Al content, decreased Ta content, and the Ti addition. W and Co exhibited an

increase in k'B of similar magnitude due to the change in Ta and Al concentrations with

Ti in the matrix. The segregation of Cr had no appreciable change with the modification

in alloy chemistry. Ti showed a greater degree of segregation than any other addition that

partitioned to the interdendritic region. The k'B for Ti in LMSX-15 was slightly lower

than that of LMSX-14 indicating an increase in partitioning with increasing Ta and

decreasing Al contents. Ni and Al both exhibited similar increases in segregation with

alloy modifications. Ta showed no change in segregation due to these changes in base

alloy chemistry.

4.4. Segregation Behavior

The use of partitioning coefficients to describe the segregation of elements in an as-

cast alloy is useful to understand castability, defect formation, and heat treatment

requirements. However, the magnitude of segregation obtained from the calculation of

the partitioning coefficient may not be indicative of the degree of segregation that is

occurring. Also, in an element that shows a relatively wide scatter and no visible

partitioning preference, (i.e. Cr in this experiment) the actual partitioning, dendritic or

interdendritic, that is occurring may not be accurate in all cases.

The line scans used in this study, develop a graphical representation of the

compositional variations that occur, due to segregation after solidification and some

degree of back diffusion have occurred. Figure 4-37 depicts this segregation between

dendrites as a surface that has a varying composition depending on the distance from the

dendrite itself. The curved lines between the dendrite cores is an idealized representation














Partitioning Interaction due to Decreasing Ta with a Ti Addition

3 50



300



250

Cr
---WCo
2 00 -- ---



1 50



1 00








1 14
Alloy (LMSX-X)


Figure 4-31: Partitioning trends for elements between in LMSX-1 and-14. Elements

segregating to the dendritic region shown. Difference in the two alloys is that

LMSX-14 contains 6.00 wt% Ta and an addition of 0.80 wt% Ti.



Partitioning Interaction due to Decreasing Ta with a Ti Addition

1 00

090

080


070 1 --N -

060

S050

0 40

030








1 14
Alloy (LMSX-X)


Figure 4-32: Partitioning trends for elements between in LMSX-1 and-14. Elements

segregating to the interdendritic region shown. Difference in the two alloys is

that LMSX-14 contains 6.00 wt% Ta and an addition of 0.80 wt% Ti.









66




Partitioning Interaction Due to Decreasing Al and a Ti Addition

4 50


400-


350


300 -
Cr
250 --- Co
-W
-0- Re
200


1 50









1 15
Alloy (LMSX-X)


Figure 4-33: Partitioning trends for elements between in LMSX-1 and-15. Elements

segregating to the dendritic region shown. Difference in the two alloys is that

LMSX-15 contains 5.10 wt% Al and an addition of 0.80 wt% Ti.



Partitioning Interaction Due to Decreasing Al and a Ti Addition

1 00

090

080

070

e Ta
0 60-A

A Tl
050

0 40
A

0 30








1 15
Alloy (LMSX-X)


Figure 4-34: Partitioning trends for elements between in LMSX-1 and-15. Elements

segregating to the interdendritic region shown. Difference in the two alloys is

that LMSX-15 contains 5.10 wt% Al and an addition of 0.80 wt% Ti.









67





Partitioning Interactions Due to Varying Ta and Al with an Addition of Ti


400


350


3 00
-Cr
-Co
250--
-4----Re
2 00


I 5O


Alloy (LMSX-X)


Figure 4-35: Partitioning trends for elements between in LMSX-14 and-15. Elements

segregating to the dendritic region shown.


Partitioning Interactions Due to Varying Ta and Al with an Addition of Ti


1 00


090


080


070 -


0 60


". 050


040


030


-@-Ta
--Al


Alloy (LMSX-X)


Figure 4-36: Partitioning trends for elements between in LMSX-14 and-15. Elements

segregating to the interdendritic region shown.


r --------rf


I '"'









of solidification, back diffusion, and segregation of an element that segregates to the

dendrite core. Note that the composition of the interdendritic region is depleted in the

element while the core is enriched. Also it should be noted that the

solidification/segregation lines are represented by curves. The use of curves was based

on the observation of the general trends of the data points determined by EMPA.

For each set of EMPA data points, a second order trendline was determined and

then the equation that describes the trendline was determined. This was done for a

normalized primary dendrite arm spacing (PDAS). Using this second order equation, the

curvature for the trendline was determined.

Curvature is defined as "the amount by which a curve, surface, or other manifold

deviates from a straight line.42" Mathematically, curvature, or K comes from the second

derivative of an equation, or more explicitly, 42

a2y
82
K= 2 equation (4-1)




But this can be simplified to just the second derivative as previously mentioned due to the

desire to determine the maximum value for the given equation. Thus, putting this in

terms of the trendline equations, it is simply 2a (where a is from ax2 + bx + c from the

trendline equation) because the only point of concern is at the apex which can be

considered x = 0. It should be noted that care should be taken with the calculation of the

curvature, K. The sign ofK is determine by the line scan itself. Since the line scans in

this experiment were done from dendrite core to dendrite core through the interdendritic

region, one combination of positive and negative curvature values is achieved. If the









scan were done from the interdendritic region, through the dendrite core, and back into

the interdendritic region, another combination of positive and negative K's are returned

which are the opposite sign of the first example. By doing the scans dendrite core to

dendrite core, the resultant signs reflect those done by the previous k' analysis in this and

other studies.


















Figure 4-37: Red lines indicated solidification/segregation gradients between dendrite
cores within the interdendritic region for an element that segregates to the
dendrite cores. The dendrites are represented in yellow.

With the trendline equations determined, the K could be calculated. K was used to

explain the segregation behavior in the various alloys. The curvature, K, values were

calculated and then plotted against the following:

* Cobalt. By comparing LMSX-1, -2, and -3.

* Chromium. By comparing LMSX-1, -5, and -5.

* Rhenium. By comparing LMSX-1, -9, -10, and -11.

* Ruthenium. By comparing LMSX-1, -16, and -17.

* Tungsten. By comparing LMSX-1 and 6.

* Molybdenum. By comparing LMSX-1 and -8









* Palladium. By comparing LMSX-1 and -18.

* Tungsten with a Molybdenum addition. By comparing LMSX-7 and -8.

* Variation of Tantalum and Aluminum from the baseline. LMSX-1, -12, and
LMSX-1, -13.

* Variation between Tantalum and Aluminum. LMSX-12 and -13.

* Variation of Tantalum and Aluminum from the baseline with an addition of
Titanium. LMSX-1, -14, and LMSX-1, -15.

* Variation between Tantalum and Aluminum with an addition of Titanium. LMSX-
14 and -15.

* V Variation between decreasing Tungsten and increasing Molybdenum. LMSX-1,
-7 and -6, -8

Table 4-3 contains the K values and the k'B values for comparison purposes.

Similar to previous results, the trend of k' greater than unity indicated segregation to the

dendrite core, along with K greater than zero was consistent for partitioning to the

dendritic regions for the eighteen model alloys.11,35 Similarly, the trend of k' less than

unity and K less than zero was also consistent with previous results for the eighteen

model alloys, indicating consistency in determining overall segregation path to the

interdendritic regions. Although most results for these comparisons were similar, there

was some disagreement in the elements that showed only a weak segregation preference

between the dendritic and interdendritic region.

4.4.1. Cobalt Segregation Behavior

The K value was calculated for each element in each of LMSX-1, -2, and -3 and

then plotted against increasing Co concentration. Figure 4-38 shows the extent of change

of K resulting from this compositional variation. Cr, Ni, W, and Re all partitioned to the

dendritic region, and Al, Ni, and Ta all segregated to the interdendritic region. The









elements W, Re, Ta, and Al all show a decrease in their segregation as the Co content

was increased. Co and Ni segregated slightly more. Cr segregation did not change

significantly. Re segregates more than any of the elements in these alloys over all

concentrations of Co, and exhibited a maximum in segregation at 4 wt% Co. Re

segregation decreased slightly with the addition of 4 wt% Co to the alloy (for a total of

8 wt% Co). With 12.2 wt% Co present in the alloy, the KRe dropped to the lowest level in

this study. Ta showed the next greatest effect due to increasing Co content. The increase

in Co from 4 wt% to 8 wt% showed little effect on Ta, but the segregation began to

decrease (become less negative) when the Co concentration was increased to 12.2 wt%.

Ni showed the third greatest segregation behavior in this series of alloys. The

increase in Co concentration caused an initial increase in partitioning of Ni when Co was

increased from 4 wt% to 8 wt%. The remaining increase in Co had no further effect on

the segregation ofNi. W showed a linear decrease in segregation as the Co content was

increased from 4 wt% to 12.2 wt%. The segregation of Co followed a more expected

trend of increasing as the concentration of it increased in the system from 4 wt% to 8

wt% Co, but did not change beyond the 8wt% Co concentration. Kco in LMSX-3 was the

lowest value for Co found in this part of this investigation. The partitioning of Al was the

opposite of the trend observed by Co. There was no change in Al segregation from 4

wt% Co to 8 wt% Co, and then the partitioning decreased with further additions of Co.

4.4.2. Chromium Segregation Behavior

LMSX-4, -1, and -5 were used to evaluate the segregation behavior of the elements

in the alloys with varying Cr contents. LMSX-5 contained 2.1 wt% Cr and LMSX-4

contained 6.15 wt% Cr. This analysis is presented from the low Cr content alloy to the









high content alloy (Figure 4-39). When the analysis was preformed, Re was observed to

exhibit the greatest degree of segregation and it partitioned to the dendritic region. The

low and baseline levels of Cr had little effect on the segregation behavior, but the

addition of 4.15 wt% Cr to the high Cr (LMSX-4, 6.15 wt% Cr) brought about a decrease

in Re segregation. Ta segregated to the interdendritic region and was the second most

strongly segregated element. As Cr was added, the partitioning of Ta increased and then

remained relatively constant. The addition of Cr brought about a decrease in the third

most heavily partitioned element, Ni, which segregated to the interdendritic region. As

the Cr content was increased, the partitioning of Ni decreased in a linear manner. W

partitioned to the dendritic region and its segregation decreased linearly as the Cr content

increased. Co and Cr both segregated to the dendrite cores, and both showed only slight

increases in segregation due to increasing Cr content. However, Co did segregate more

strongly than Cr over the entire range of compositions evaluated. Cr exhibited a

complete change in segregation. In high Cr alloy (LMSX-4, 6.15 wt% Cr) and the

baseline, Cr was observed to segregate to the dendritic regions. Whereas in low Cr

content alloys (LMSX-5, 2.1 wt% Cr) was observed to segregate to the interdendritic

region. The increasing the Cr content caused Al to segregate to a slightly less, and Al

segregated to the interdendritic region. Kcr in LMSX-5 was almost zero indicating no

preference in segregation.












Table 4-3: Comparison of values calculated by k'B and K.
Alloy Method Ni Cr Co Mo W Re Ta Al Ti Ru Pd
1 K -32.91 0.75 10.02 16.55 47.80 -44.98 -9.12
k'B 0.91 1.04 1.14 1.58 3.10 0.48 0.75
2 K -31.31 2.39 11.60 19.58 55.81 -44.98 -12.59
k'B 0.94 1.20 1.18 1.57 3.04 0.48 0.73
3 K -27.81 0.88 5.29 22.36 57.96 -45.69 -13.01
k'B 0.94 1.07 1.23 1.87 4.86 0.44 0.70
4 K -21.36 1.82 9.59 13.90 40.77 -35.69 -8.98
k'B 0.93 1.05 1.19 1.52 3.08 0.46 0.81
5 K -35.63 -0.20 9.59 17.64 47.36 -27.00 -9.12
k'B 0.94 0.98 1.04 1.64 2.59 0.54 0.78
6 K -41.48 1.71 14.39 29.20 49.66 -38.49 -14.91
k'B 0.93 1.03 1.16 1.89 2.69 0.41 0.69
7 K -15.25 0.18 9.31 -2.63 5.29 39.58 -28.92 -7.55
k'B 0.97 1.10 1.06 0.88 1.41 2.35 0.54 0.84
8 K -25.39 1.06 10.64 -1.39 12.75 39.99 -28.65 -9.11
k'B 0.94 1.03 1.06 0.82 1.46 2.48 0.50 0.85
9 K 1.26 -2.27 5.49 17.99 0.00 -25.92 -4.15
k'B 1.01 1.00 1.11 1.62 0.00 0.61 0.86
10 K -16.92 2.35 14.02 22.23 31.82 -45.59 -7.82
k'B 0.96 1.07 1.19 1.60 3.41 0.50 0.83
11 K -65.36 5.71 16.86 15.51 86.65 -42.52 -16.80
k'B 0.87 1.28 1.25 1.73 6.70 0.34 0.65
12 K -28.80 2.81 13.11 16.91 47.08 -40.80 -10.27
k'B 0.94 1.13 1.15 1.57 2.67 0.54 0.77












Table 4-3 (cont.): Comparison of values calculated by k'B and K.
Alloy Method Ni Cr Co Mo W Re Ta Al Ti Ru Pd
13 K -50.02 -1.89 11.24 22.54 59.26 -25.75 -15.32
k'B 0.89 0.89 1.20 2.07 5.86 0.34 0.69
14 K -41.27 0.64 10.70 22.41 43.09 -18.99 -11.04 -5.59
k'B 0.93 1.19 1.10 1.83 3.12 0.44 0.72 0.42
15 K -30.16 2.07 13.03 19.63 46.81 -30.01 -9.43 -7.14
k'B 0.91 1.14 1.22 1.91 4.03 0.45 0.71 0.37
16 K -33.63 1.62 11.37 16.01 46.51 -31.27 -11.31 0.84
k'B 0.93 1.12 1.19 1.52 2.96 0.47 1.02 1.18
17 K -49.64 5.45 17.68 20.62 64.85 -46.59 -15.08 2.75
k'B 0.90 1.15 1.25 1.86 5.75 0.35 0.71 1.15
18 K -30.19 3.28 18.05 22.04 57.72 -36.08 -15.76 -19.12
18 B 0.93 1.11 1.24 2.08 4.54 0.44 0.68 0.27
k'B 0.93 1.11 1.24 2.08 4.54 0.44 0.68 0.27












4.4.3. Rhenium Segregation Behavior


Re is the element that defines the different generations of superalloys and this part


of the investigation deals with the effects of segregation due to increasing Re content


from 0 wt% Re (LMSX-9, a first generation model superalloy), to 3 wt% Re (LMSXS-


10, a second generation model superalloy), and finally reaching 6 wt% Re (LMSX-1), a


third generation model superalloy. To begin to understand the effect of larger quantities


or Re on an alloy, an additional 3 wt% Re was added in LMSX-11. This discussion will


be related in terms of increasing Re content from 0 wt% to 8.9 wt%. See Figure 4-40 for


graphical representation of the presented information.


Normalized Partitioning due to Co

8000


6000 -

--- N
4000 --Cr
A Co

20 00 -- Re -
W Ta

000
4 6 8 10 12 1

-20 00


-40 00 -


-60 00
wlo Co

Figure 4-38: Elemental segregation plots based on K due to increasing Co content from 4
wt% to 12.2 wt%.












Normalized Partitioning due to Cr

6000

50 00



30 00

20 00


X)- Re
000 ----Ta
Al 2 3 4 5 6
1000

-20 00

3000

-40 00

-50 00
wlo Cr

Figure 4-39: Elemental segregation plots based on K due to increasing Cr content from
2.1 wt% to 6.15 wt%.

Re was the most segregated element in the alloys examined in this series, and the


degree of segregation increased as more Re was added to the system. Re segregated to the


dendritic region, and the K for Re in LMSX-11 was the largest observed in this study. Ta,


which partitioned to the interdendritic region exhibited an initial increase in segregation


when 1 at% Re was added to the system. After this point, the segregation varied, but


remained relatively constant and did not increase further. Ni was found to segregate to


the dendrite core in LMSX-9 (0 wt% Re), and then began to partition to the interdendritic


region, with increasing Re content. The final addition of Re (to 8.9 wt%) caused a large


increase in the segregation behavior of Ni, and KNi became more negative than that of KTa


indicating even more Ni segregation was occurring than Ta. W showed less segregation


than Ni, and it segregated to the dendritic region. The increase in Re did not affect the


segregation behavior of W significantly. The overall behavior of W was nearly constant,









although a slight decrease in segregation was observed. Co initially showed very little

segregation in LMSX-9, but the addition of 1 at% Re increased its partitioning to the

dendritic core. Further additions of Re brought about a slight increase in segregation in

Co. Al segregated to the interdendritic region, and the segregation behavior for Al did

not change from the 0, 1, and 2 at% Re concentrations. The addition of the final 1 at%

Re caused the segregation to increase slightly. Cr was observed to segregate to the

interdendritic region in LMSX-9, but after Re was added, it began to segregate to the

dendritic region. As the Re content was increased, a slow, linear increase in the

segregation of Cr was observed.

LMSX-11 contained four of the strongest segregating elements in this entire

investigation. Ni and Al were the most heavily segregated to the interdendritic region,

and Re were the most heavily segregated to the dendritic core followed by either W and

Co, both of which were observed to have the same degree of segregation. However,

minimums in the segregation behavior of several elements were observed in the low Re

alloys. KA1 was the lowest in LMSX-9, and KRe was at its lowest in LMSX-10.












Normalized Partitioning due to Re

100




60

40

-U-Cr
20 CO
-4 .. ..----------- w -- -- -





wo ReR








Figure 4-40: Elemental segregation plots based on K due to increasing Re content from 0
wt% to 8.9 wt%.
-40

-60

-80
wlo Re


Figure 4-40: Elemental segregation plots based on K due to increasing Re content from 0
wt% to 8.9 wt%.


4.4.4. Tungsten Segregation Behavior

W was studied at two levels: the baseline LMSX-1 (5.85 wt% W) and an increased


level ofW in LMSX-6 (8.6 wt% W). The first observation was that by increasing the W


concentration, all of the elements in the alloys (Ni, Cr, Co, W, Re, Ta, and Al) segregated


more strongly (Figure 4-41). Re, W, Co, and Cr all segregated to the dendrite core. The


degree of segregation was also in this order with Re being the most heavily partitioned,


and Cr being the least partitioned. Ta, Ni, and Al all partitioned to the interdendritic


region. At the low W level (5.85 wt%), Ta segregated the most strongly, followed by Ni


and then Al. When segregation was examined at the high W level (8.6 wt%), Ni and Ta


switched making Ni the most heavily partitioned element segregating to the interdendritic


region. In LMSX-6, W was found to segregate more strongly than in any other alloy in


this study.












Normalized Partitioning varying W

6000

\-Q--NI
-H--Cr
40 00-



2000 Al
-X-W





r 000 -
5.5 6 6.5 7 7.5 8 8.5 9 95

-20 00



-40 00



-60 00
wlo W


Figure 4-41: Elemental segregation plots based on K due to increasing W content from
5.85 wt% to 8.6 wt%.


4.4.5. Tungsten Segregation Behavior with an Addition of Molybdenum


With the addition of 1 at% Mo, LMSX-7 and -8 could be compared to examine the


effects of partitioning with a variation in W. The difference in these to alloys is the


reduced W content of LMSX-7 to 3.1 wt% from 5.85 wt%.


Increasing the W content had little effect on the two most heavily segregated


elements (Figure 4-42). Re, the most heavily segregated of all, remained segregated to


the dendrite core regions. Ta, the second most heavily segregated element, still


segregated to the interdendritic region. Ni was still segregating to the interdendritic


regions and partitioned more strongly as W was added. The increase in KNi with


increasing W was the largest observed in this set of alloys. Initially, Co partitioned more


than W itself to the dendritic region. But after increasing the W concentration, W


segregated more strongly than Co. Al segregated to the interdendritic region. As the W









content was increased, Al began to partition to a slightly greater degree, but not to the

extent of the other elements with the exception of Re and Ta. Cr showed only a small

increase in its behavior of partitioning to the dendritic region, as W was added. Mo,

which partitioned to the interdendritic region, exhibited less segregation as more W was

added to the system. The lowest degree of W segregation, Kw, in this study was observed

in LMSX-7.

4.4.6. Molybdenum Segregation Behavior

Using the baseline LMSX-1 (0 wt% Mo) and comparing it to LMSX-8 (1.6 wt%

Mo), the segregation behavior of Mo could be ascertained. Of the elements that

segregated to the dendrite core region, Re segregated the most, followed by W, then Co,

and finally Cr (Figure 4-43). The elements that segregated to the interdendritic region

were Ta, Ni, Al, and Mo (in order from greatest degree of segregation to least). Re was

the most heavily segregated, and Ta was the second most segregated. The addition of Mo

caused both Re and Ta to segregate less, and by about the same amount. This change in

chemistry also led to a decrease in the segregation Ni and to a lesser degree, W. Al and

Cr had no observable change in segregation behavior due to the addition of 1 at% Mo.

The segregation of Co increased slightly with the addition of Mo.

4.4.7. Ruthenium Segregation Behavior

LMSX-16 and -17 both contained an addition of 1 and 2 (1.6 and 3.2) at% (wt%)

Ru respectively. Analyses were done on the EMPA data to determine the effect of an

addition of Ru on the partitioning of all elements contained in these alloys, and compared

The elements that segregated to the dendritic region (in order of greatest to least) were

Re, W, Co, Cr, and Ru (Figure 4-44). All the other elements (Ni, Ta, and Al) partitioned

to the interdendritic region. The initial addition of 1 at% Ru only showed an effect on the




Full Text

PAGE 1

A NEW METHOD FOR THE MODELING OF ELEMENTAL SEGREGATION BEHAVIOR AND PARTITIONING IN SINGLE CRYSTAL NICKEL BASE SUPERALLOYS By ERIC CHRISTOPHER CALDWELL A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2004

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Copyright 2004 by Eric Christopher Caldwell

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This work is dedicated to my family a nd friends who have been with me through good times and bad. And for those who travel in ha rms way, there is a light at the end of the tunnel. Godspeed!

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Nothing of value is free from Starship Troopers by Robert A. Heinlein

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v ACKNOWLEDGMENTS The author would like to thank and to acknowledge the support of Dr. Gerhard Fuchs for providing the way and the means, Dr Reza Abbaschian and Dr. Robert DeHoff for support and consultation, and my fam ily and friends for their support and understanding, especially Dr Daniel Villanueva for making me realize that I was in the wrong career. Additional thanks go to Wayne Ac ree and the staff of the Major Analytical Instrument Center (MAIC) at the Univers ity of Florida, and oddly enough, the United States Navy for giving me the backbone, c ourage and dedication to see the job done. This material is based on work suppor ted by the National Sc ience Foundation under Grant No. 0072671.

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vi TABLE OF CONTENTS page ACKNOWLEDGMENTS...................................................................................................v LIST OF TABLES.............................................................................................................ix LIST OF FIGURES...........................................................................................................xi ABSTRACT.....................................................................................................................xi x CHAPTER 1 INTRODUCTION........................................................................................................1 2 LITERATURE SEARCH.............................................................................................9 2.1. Evolution of Nickel Based Superalloys.................................................................9 2.1.1. The Matrix..........................................................................................10 2.1.2. Casting and Specialized Processing Techniques.......................................14 3 MATERIALS AND EXPERIMENTAL PROCEDURE...........................................19 3.1. Materials..............................................................................................................19 3.2. Metallography......................................................................................................21 3.3. Scanning Electron Microscopy/B ackscatter Electron Microscopy.....................24 3.3.1. Electron Microprobe Analysis...................................................................26 3.3.2. Verification of Applicability of Analysis..................................................28 4 EXPERIMENTAL RESULTS...................................................................................29 4.1. Primary Dendrite Arm Spacing...........................................................................29 4.2. Electron Microprobe Analysis.............................................................................30 4.3. Elemental Segregation and Partitioning..............................................................32 4.3.1. Cobalt Partitioning.....................................................................................38 4.3.2. Chromium Partitioning..............................................................................39 4.3.3. Rhenium Partitioning.................................................................................43 4.3.4. Tungsten partitioning.................................................................................46 4.3.5. Tungsten Partitioning with an Addition of Molybdenum.........................47 4.3.6. Molybdenum Partitioning..........................................................................51 4.3.7. Ruthenium Partitioning.............................................................................51

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vii 4.3.8. Palladium Partitioning...............................................................................52 4.3.9. Tungsten and Molybdenum Partitioning Interactions...............................55 4.3.10. Tantalum and Aluminum Partitioning Interactions.................................57 4.3.11. Tantalum and Aluminum Partitioning Interactions with an Addition of Titanium...........................................................................................................60 4.4. Segregation Behavior...........................................................................................64 4.4.1. Cobalt Segregation Behavior.....................................................................70 4.4.2. Chromium Segregation Behavior..............................................................71 4.4.3. Rhenium Segregation Behavior.................................................................75 4.4.4. Tungsten Segregation Behavior................................................................78 4.4.5. Tungsten Segregation Behavior with an Addition of Molybdenum.........79 4.4.6. Molybdenum Segregation Behavior..........................................................80 4.4.7. Ruthenium Segregation Behavior..............................................................80 4.4.8. Palladium Segregation Behavior...............................................................83 4.4.9. Tungsten and Molybdenum Segreg ation Behavior Interactions...............83 4.4.10. Tantalum and Aluminum Segreg ation Behavior Interactions.................87 4.4.11. Tantalum and Aluminum Segregati on Behavior with an Addition of Titanium...........................................................................................................88 4.5. Scheil Analysis and Comparison.........................................................................92 4.6. Verification of Applicability of Analysis............................................................96 5 DISCUSSION.............................................................................................................98 5.1. Primary Dendrite Arm Spacing.........................................................................100 5.2. Partitioning Coefficient and Segregation...........................................................101 5.2.1. Comparison of k and Techniques for Examining Segregation...........101 5.2.2. Cobalt Effects..........................................................................................105 5.2.3. Chromium Effects...................................................................................107 5.2.4. Rhenium Effects......................................................................................109 5.2.5. Tungsten Effects......................................................................................111 5.2.6. Tungsten Effects with an Addition of Molybdenum...............................113 5.2.7. Molybdenum Effects...............................................................................114 5.2.8. Ruthenium Effects...................................................................................115 5.2.9. Palladium Effects.....................................................................................117 5.2.10. Tungsten and Molybdenum Effects.......................................................118 5.2.11. Tantalum and Aluminum Effects..........................................................120 5.2.11.1 Effect of increased tantal um with decreased aluminum...............120 5.2.11.2. Effect of decreased tantalum and increased aluminum...............121 5.2.12. Tantalum and Aluminum Effects with an Addition of Titanium..........123 5.2.12.1. Effect of decreased tantalum with titanium.................................123 5.2.12.2. Effect of decreased aluminum with titanium..............................125 5.3. Scheil Analysis..................................................................................................127 5.3.1. Analysis of LMSX-3...............................................................................128 5.3.2. Analysis of CMSX-4...............................................................................128 6 CONCLUSIONS......................................................................................................133

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viii 7 FUTURE WORK......................................................................................................138 7.1. Solidification Front Curves from EMPA...........................................................138 7.2. Other Elemental Interaction...............................................................................139 APPENDIX A SAMPLE BACKSCATTERED ELECTRON IMAGES.........................................141 B ELECTRON MICROPROBE ANALYSIS SCHEDULES AND SUMMARY OF PROCEDURE USED...............................................................................................160 C AVERAGE ELECTRON MICROPROBE ANALYSES RESULTS......................163 D SCHEIL ANALYSIS GRAPHS FOR LMSX-3.......................................................182 E SCHEIL ANALYSIS DATA AND GRAPHS FOR CMSX-4.................................195 F SCHEIL ANALYSIS GRAPHS FOR LMSX-3.......................................................204 G SCHEIL ANALYSIS DATA AND GRAPHS FOR CMSX-4.................................217 LIST OF REFERENCES.................................................................................................226 BIOGRAPHICAL SKETCH...........................................................................................230

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ix LIST OF TABLES Table page 3-1 Compositions of the 18 model alloys in weight percent (wt%)...............................22 3-2 Composition of CMSX-4 in wt%.4,6........................................................................28 4-1 PDAS measurements from EMPA and from hand calculations..............................31 4-2 Showing weight percentages of each respective element in each alloy from the dendrite core and the interdendritic re gion, and the calculated k value for both techniques A (in orange ), and B (in blue)................................................................35 4-3 Comparison of values calculated by kB and .........................................................73 4-4 Comparison of kB and for CMSX-4....................................................................97 5-1 i for the eighteen model alloys and CMSX -4 listed in order from lowest to highest....................................................................................................................105 6-1 Elemental segregation effects for each combination of alloy compared................136 7-1 Recommended alloying variati ons to investigate in wt%......................................139 7-2 Recommended alloying va riations based on at%...................................................140 C-1 Average EMPA data for LMSX-1.........................................................................164 C-2 Average EMPA data for LMSX-2.........................................................................165 C-3 Average EMPA data for LMSX-3.........................................................................166 C-4 Average EMPA data for LMSX-4.........................................................................167 C-5 Average EMPA data for LMSX-5.........................................................................168 C-6 Average EMPA data for LMSX-6.........................................................................169 C-7 Average EMPA data for LMSX-7.........................................................................170 C-8 Average EMPA data for LMSX-8.........................................................................171

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x C-9 Average EMPA data for LMSX-9.........................................................................172 C-10 Average EMPA data for LMSX-10.......................................................................173 C-11 Average EMPA data for LMSX-11.......................................................................174 C-12 Average EMPA data for LMSX-12.......................................................................175 C-13 Average EMPA data for LMSX-13.......................................................................176 C-14 Average EMPA data for LMSX-14.......................................................................177 C-15 Average EMPA data for LMSX-15.......................................................................178 C-16 Average EMPA data for LMSX-16.......................................................................179 C-17 Average EMPA data for LMSX-17.......................................................................180 C-18 Average EMPA data for LMSX-18.......................................................................181 E-1 Scheil curve data for CMSX-4...............................................................................201 F-1 EMPA data for LMSX-3 Scheil analysis...............................................................209 G-1 Scheil curve data for CMSX-4...............................................................................223

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xi LIST OF FIGURES Figure page 2-1 The matrix from model alloy LMSX-15. Image taken at 10kx. matrix and precipitates are labeled.............................................................................................10 2-2 Al-Ni phase diagram. The AlNi3 field is visible at 85 87 wt% Ni.......................11 2-3 FCC matrix shown above left and L12 ordered phase of Ni3Al (Ni shown in black) above right.6.............................................................................................................11 2-4 Ni-Al-X ternary phase diagram. The Ni3Al phase fields are shown in the phase diagram with the various other additions, indicating large regions of solubility.....14 2-5 The improvements in alloy elongation and rupture strength for the same alloys (M252 and Waspalloy) for vacuum melt and air melt..................................................15 2-6 DS casting operation is shown on the le ft and SX casting operations are shown on the right. The primary difference is the use of a constricto r or single crystal selector.....................................................................................................................17 3-1 BSE image of LMSX-1 taken at 100x equivalent....................................................25 3-2 BSE image of LMSX-13 taken at 100x equivalent..................................................25 3-3 BSE photo of LMSX-1 taken at 100x equi valent. Yellow line i ndicates location of the line scan preformed............................................................................................27 4-1 BSE image of LMSX-13. Black lines added to image were where PDAS measurements were taken.........................................................................................30 4-2 k values for LMSX-1 for techniques A (o range) and B (blue). The green line is at k = 1........................................................................................................................4 0 4-3 k values for LMSX-13 for techniques A (orange) and B (blue). The green line is at k = 1....................................................................................................................40 4-4 k values for LMSX-18 for techniques A (orange) and B (blue). The green line is at k = 1....................................................................................................................41 4-5 k values for LMSX-8 for techniques A (o range) and B (blue). The green line is at k = 1. The difference is noted by a circle...............................................................41

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xii 4-6 Mo segregation plot for LMSX-7 a nd -8. White points were used in kB analysis. Second order trendlines are al so shown for both alloys...........................................42 4-7 Al segregation plot for LMSX-1 and 18 shown for comparison. White points were used in kB analysis. Second order trendlines are also shown for all alloys............42 4-8 Partitioning effects due to increasing Co concentration for elements showing a preference to segregate to the dendritic region........................................................44 4-9 Partitioning effects due to increasing Co concentration for elements showing a preference to segregate to th e interdendritic region.................................................44 4-10 Partitioning effects due to increasing Cr concentration for elements showing a preference to segregate to the dendritic region........................................................45 4-11 Partitioning effects due to increasing Cr concentration for elements showing a preference to segregate to th e interdendritic region.................................................45 4-12 Partitioning effects due to increasing Re concentration for elements showing a preference to segregate to the dendritic region........................................................48 4-13 Partitioning effects due to increasing Re concentration for elements showing a preference to segregate to th e interdendritic region.................................................48 4-14 Partitioning effects due to increasing W concentration for element segregating to the dendritic region...................................................................................................49 4-15 Partitioning effects due to increasing W concentration for element segregating to the interdendritic region...........................................................................................49 4-16 Partitioning effects due to decreasing W concentration with the addition of 1 at% Mo for element segregating to the dendritic region.................................................50 4-17 Partitioning effects due to decreasing W concentration with the addition of 1 at% Mo for element segregating to the interdendritic region..........................................50 4-18 Partitioning effects due to the addition of 1 at% Mo for element segregating to the dendritic region........................................................................................................53 4-19 Partitioning effects due to the addition of 1 at% Mo for element segregating to the interdendritic region.................................................................................................53 4-20 Partitioning effects due to Ru addition for element segregating to the dendritic region........................................................................................................................5 4 4-21 Partitioning effects due to Ru addition fo r element segregating to the interdendritic region........................................................................................................................5 4

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xiii 4-22 Partitioning effects due to Pd addition for element segregating to the dendritic region........................................................................................................................5 6 4-23 Partitioning effects due to Pd addition for element segregating to the interdendritic region........................................................................................................................5 6 4-24 Partitioning trends for elements in LMSX -1 and-7. Difference in the two alloys is that LMSX-7 contains 3.1 wt% W and an addition of 1.6 wt% Mo........................58 4-25 Partitioning trends for elements in LMSX-6 and -8. Difference in the alloys is that LMSX-6 contains 8.6 wt% W, 0 wt% M o, and LMSX-8 contains 5.85 wt% W, 1.6 wt% Mo....................................................................................................................58 4-26 Partitioning trends for elements between in LMSX-1 and-12. Difference in the two alloys is that LMSX-12 contai ns 11.2 wt% Ta and 5.0 wt% Al..............................61 4-27 Partitioning trends for elements between in LMSX-1 and-13. Elements segregating to the dendritic region show n. Difference in the two alloys is that LMSX-13 contains 6.00 wt% Ta and 6.15 wt% Al...................................................................61 4-28 Partitioning trends for elements between in LMSX-1 and-13. Elements segregating to the interdendritic region shown. Difference in the two alloys is that LMSX-13 contains 6.00 wt% Ta and 6.15 wt% Al...................................................................62 4-29 Partitioning trends for elements be tween in LMSX-12 and-13. Elements segregating to the de ndritic region shown................................................................62 4-30 Partitioning trends for elements be tween in LMSX-12 and-13. Elements segregating to the interd endritic region shown........................................................63 4-31 Partitioning trends for elements between in LMSX-1 and-14. Elements segregating to the dendritic region show n. Difference in the two alloys is that LMSX-14 contains 6.00 wt% Ta and an addition of 0.80 wt% Ti............................................65 4-32 Partitioning trends for elements between in LMSX-1 and-14. Elements segregating to the interdendritic region shown. Difference in the two alloys is that LMSX-14 contains 6.00 wt% Ta and an addition of 0.80 wt% Ti............................................65 4-33 Partitioning trends for elements between in LMSX-1 and-15. Elements segregating to the dendritic region show n. Difference in the two alloys is that LMSX-15 contains 5.10 wt% Al and an addition of 0.80 wt% Ti............................................66 4-34 Partitioning trends for elements between in LMSX-1 and-15. Elements segregating to the interdendritic region shown. Difference in the two alloys is that LMSX-15 contains 5.10 wt% Al and an addition of 0.80 wt% Ti............................................66 4-35 Partitioning trends for elements be tween in LMSX-14 and-15. Elements segregating to the de ndritic region shown................................................................67

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xiv 4-36 Partitioning trends for elements be tween in LMSX-14 and-15. Elements segregating to the interd endritic region shown........................................................67 4-37 Red lines indicated soli dification/segregation gradie nts between dendrite cores within the interdendritic region for an elemen t that segregates to the dendrite cores. The dendrites are represented in yellow...................................................................69 4-38 Elemental segregation plots based on due to increasing Co content from 4 wt% to 12.2 wt%...................................................................................................................75 4-39 Elemental segregation plots based on due to increasing Cr content from 2.1 wt% to 6.15 wt%..............................................................................................................76 4-40 Elemental segregation plots based on due to increasing Re content from 0 wt% to 8.9 wt%.....................................................................................................................78 4-41 Elemental segregation plots based on due to increasing W content from 5.85 wt% to 8.6 wt%................................................................................................................79 4-42 Elemental segregation plots based on due to increasing W content from 3.1 wt% to 5.85 wt% with an addition of 1.6 wt% Mo to the alloys......................................82 4-43 Element segregation plots based on due to increasing Mo content from 0 wt% to 1.6 wt%.....................................................................................................................82 4-44 Element segregation plots based on due to increasing Ru content from 0 wt% to 3.2 wt%.....................................................................................................................84 4-45 Elemental segregation plots based on due to increasing Pd content from 0 wt% to 1.7 wt%.....................................................................................................................84 4-46 Elemental segregation plots based on due to decreasing W to 3.1 wt% and adding 1.6 wt % Mo.............................................................................................................86 4-47 Elemental segregation plot based on due to decreasing W to 5.85 wt% and adding 1.6 wt% Mo..................................................................................................86 4-48 Elemental segregation plots based on due to increasing Ta to 11.2 wt% and decreasing Al to 5 wt%............................................................................................89 4-49 Elemental segregation plots based on due to decreasing Ta to 6.0 wt% and increasing Al to 6.15 wt%........................................................................................89 4-50 Elemental segregation plots based on due to changing Ta and Al concentrations. Compilation of Figures 4-48 and 4-49.....................................................................90 4-51 Elemental segregation plots based on due to decreasing Ta to 6.0 wt% and a Ti addition of 0.80 wt%................................................................................................93

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xv 4-52 Elemental segregation plots based on due to decreasing Al to 5.10 wt% and a Ti addition of 0.80 wt%................................................................................................93 4-53 Elemental segregation plots based on due to changing Ta and Al concentrations with a Ti addition. Compilation of figures 4-51 and 4-52......................................94 4-54 Scheil curve comparison for Cr done by two different techniques..........................94 4-55 Scheil curve comparison for Re done by two different techniques..........................95 4-56 Scheil curve comparison for Ta done by two different techniques..........................95 5-1 Ni segregation plot for LMSX-9, -10, -1, and -11. Trendlines were added to show degree of segregation of Ni observed as the Re content was increased.................103 5-2 Ta segregation plot for LMSX-9, -10, 1, and -11. Trendlines were added to show degree of segregation of Ni observed as the Re content was increased.................103 5-3 Example showing data for k and from two idealized elemental segregation profiles based on a normalized PDAS. Th e equations for each trendline are indicated on the graph............................................................................................104 5-4 LMSX-3 Scheil curves for Fu ll and Short techniques for Cr.................................130 5-5 LMSX-3 Scheil curves for Fu ll and Short techniques for Al.................................130 5-6 Scheil curves for Re from CMSX-4 done using the techniques described in this study.......................................................................................................................131 5-7 Scheil curves for Re from CMSX-4 from literature.43...........................................131 5-8 Scheil curves for Ta from CMSX-4 done using the techniques described in this study.......................................................................................................................131 5-9 Scheil curves for Ta from CMSX-4 from literature.43...........................................131 5-10 Scheil curves for Ti from CMSX-4 done using the techniques described in this study.......................................................................................................................132 5-11 Scheil curves for Ti from CMSX-4 from literature.43............................................132 5-12 Scheil curves for W from CMSX-4 done using the techniques described in this study.......................................................................................................................132 5-13 Scheil curves for W from CMSX-4 from literature.43............................................132 A-1 BSE image of LMSX-1 at 100x.............................................................................142 A-2 BSE image of LMSX-1 at 100x.............................................................................142

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xvi A-3 BSE image of LMSX-2 at 100x.............................................................................143 A-4 BSE image of LMSX-2 at 100x.............................................................................143 A-5 BSE image of LMSX-3 at 100x.............................................................................144 A-6 BSE image of LMSX-3 at 100x.............................................................................144 A-7 BSE image of LMSX-4 at 100x.............................................................................145 A-8 BSE image of LMSX-4 at 100x.............................................................................145 A-9 BSE image of LMSX-5 at 100x.............................................................................146 A-10 BSE image of LMSX-5 at 100x.............................................................................146 A-11 BSE image of LMSX-6 at 100x.............................................................................147 A-12 BSE image of LMSX-6 at 100x.............................................................................147 A-13 BSE image of LMSX-7 at 100x.............................................................................148 A-14 BSE image of LMSX-7 at 100x.............................................................................148 A-15 BSE image of LMSX-8 at 100x.............................................................................149 A-16 BSE image of LMSX-8 at 100x.............................................................................149 A-17 BSE image of LMSX-9 at 100x.............................................................................150 A-18 BSE image of LMSX-9 at 100x.............................................................................150 A-19 BSE image of LMSX-10 at 100x...........................................................................151 A-20 BSE image of LMSX-10 at 100x...........................................................................151 A-21 BSE image of LMSX-11 at 100x...........................................................................152 A-22 BSE image of LMSX-11 at 100x...........................................................................152 A-23 BSE image of LMSX-12 at 100x...........................................................................153 A-24 BSE image of LMSX-12 at 100x...........................................................................153 A-25 BSE image of LMSX-13 at 100x...........................................................................154 A-26 BSE image of LMSX-13 at 100x...........................................................................154 A-27 BSE image of LMSX-14 at 100x...........................................................................155

PAGE 17

xvii A-28 BSE image of LMSX-14 at 100x...........................................................................155 A-29 BSE image of LMSX-15 at 100x...........................................................................156 A-30 BSE image of LMSX-15 at 100x...........................................................................156 A-31 BSE image of LMSX-16 at 100x...........................................................................157 A-32 BSE image of LMSX-16 at 100x...........................................................................157 A-33 BSE image of LMSX-17 at 100x...........................................................................158 A-34 BSE image of LMSX-17 at 100x...........................................................................158 A-35 BSE image of LMSX-18 at 100x...........................................................................159 A-36 BSE image of LMSX-18 at 100x...........................................................................159 E-1 Scheil curve for Ni from CMSX-4.........................................................................196 E-2 Scheil curve for Cr from CMSX-4.........................................................................196 E-3 Scheil curve for Co from CMSX-4........................................................................197 E-4 Scheil curve for Mo from CMSX-4.......................................................................197 E-5 Scheil curve for W in CMSX-4..............................................................................198 E-6 Scheil curve for Re in CMSX-4.............................................................................198 E-7 Scheil curve for Ta from CMSX-4.........................................................................199 E-8 Scheil curve for Al from CMSX-4.........................................................................199 E-9 Scheil curve for Ti from CMSX-4.........................................................................200 F-1 Scheil curves comparing full and short techniques for Ni in LMSX-3..................205 F-2 Scheil curves comparing full and short techniques for Cr in LMSX-3..................205 F-3 Scheil curves for both full and sh ort techniques for Co in LMSX-3.....................206 F-4 Scheil curves for both full and sh ort techniques for W in LMSX-3......................206 F-5 Scheil curves for both long and shor t techniques for Re in LMSX-3....................207 F-6 Scheil curves for both long and shor t techniques for Ta in LMSX-3....................207 F-7 Scheil curves for both full and short techniques for Al in LMSX-3......................208

PAGE 18

xviii G-1 Scheil curve for Ni from CMSX-4.........................................................................218 G-2 Scheil curve for Cr from CMSX-4.........................................................................218 G-3 Scheil curve for Co from CMSX-4........................................................................219 G-4 Scheil curve for Mo from CMSX-4.......................................................................219 G-5 Scheil curve for W in CMSX-4..............................................................................220 G-6 Scheil curve for Re in CMSX-4.............................................................................220 G-7 Scheil curve for Ta from CMSX-4.........................................................................221 G-8 Scheil curve for Al from CMSX-4.........................................................................221 G-9 Scheil curve for Ti from CMSX-4.........................................................................222

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xix Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree Masters of Science A NEW METHOD FOR THE MODELING OF ELEMENTAL SEGREGATION BEHAVIOR AND PARTITIONING IN SINGLE CRYSTAL NICKEL BASE SUPERALLOYS By Eric Christopher Caldwell August 2004 Chair: Gerhard Fuchs Major Department: Materials Science and Engineering Ni-base superalloys are commonly used in very extreme environments where high temperature strength, good corro sion/oxidization resistance, a nd microstructural stability are required. These superalloys are made up of twelve to fifteen different elemental additions including, but not limite d to, Cr, Co, Mo, W, Re, Ta, Al, Ti, Ru, and Pd. The combinations of these elements make cas ting of a superalloy difficult and undesirable phases (the Topologically Close Packed, or TCP phases) may form in the microstructure during casting or service. TCP phases form due to localized concentra tions of specific elements. To prevent the formation of these undesirable phases and to maximize the alloys properties, solutioning heat treatments are required. Many of the solutioning heat treatment for third generation superalloys (2 at% Re) are very l ong. The length of time has to be sufficient to remove the elemental segregation th at exists within the microstructure.

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xx The elemental segregation exists upon casti ng due to alloying elements partitioning to a specific phase ( or ) or region (dendrite core or interdendritic region). A partitioning coefficient, k, is used to descri be the partitioning behavior of the alloying elements. k was observed to exhibit a diffe rent partitioning behavior than was indicated by electron microprobe line scans. A new term based on the curvature of the segregation plot, was used to qualify the direction of each elements partitioning (dendr ite core or interdendritic region), and to quantify some degree of relative segregati on between all the alloying elements in each alloy. The values for were then plotted against vary ing elemental relationships and conclusions about the segregat ion behavior were drawn.

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1 CHAPTER 1 INTRODUCTION The need for new materials is ever present and has been a driving force in technological evolution. The ga s turbine engine is a prime example of this. Due to the extreme operating conditions within the engine, most materials as well as the processes used to fabricate components are insufficient. Historically the first true application of gas turbine technology was the first jet aircraft of World War II. These aircraft we re revolutionary at the time, but severely limited operationally and cost prohibitive due to materials issues. The ME-262, the first jet powered airplane, was power ed by a Junkers Jumo 004B (F igure 1-1) turbojet engine, generating about 2,000 pounds of thrust. Howeve r, the engine could only run for around forty hours before it had to be replaced. Th is short service life was largely due to the Figure 1-1: Junkers Jumo 004A turbojet engine

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2 forged steels used in the engine. After World War II, th e jet age began, and with it the quest for higher powered and mo re reliable turbojet engines. One of the key limiting components of the tu rbojet engine (or more simply here, turbine) are the blades and vanes within the h ot section. The hot section is as the name implies: the hot part of the engine A turbojet operates under the thermodynamic Brayton cycle. The efficiency of a Brayton cycle is determined by the temperature of the first stage of the turbine. Th e higher the temperature of the fi rst stage, the more efficient and higher power the turbojet can become. Si nce more power is desired and the limiting components are in the region of the turbine se ction, these components had to be designed better and new materials used to reach the higher temperatures required to increase efficiency. The Junkers Jumo 004B blades were made of forged mild steel (SAE 1010) that had an aluminum coating for oxidization protection.3 It should be noted that the use of steel over other metals was due to availability of steel compared to other scarce strategic materials. Besides being exposed to the hi ghest temperatures within the engine, the blades and vanes are also exposed to a ve ry corrosive environment and at high stress levels. This lead the early metallurgists to select the Co-based and Ni-based metals for turbine applications, which are now called superalloys (Figure 1-2). Many of the early improvements to superall oys came from both processing and by alloying. The concept of investment casting was taken from the dental industry. With this innovation came problems such as inclusions from the mold, but investment casting was cheaper and easier to manufacture than fo rged components. The advent of vacuum induction melting (VIM) by F. N. Darmara in the 1950s reduced the problem of

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3 Figure 1-2: The change of temperature capab ilities for superalloys at the approximate time the alloy was introduced.4 inclusions to wrought processes.5 VIM made casting an even more viable alternative because purer alloys could be made with fewer inclusions. As an added benefit, additions of more reactive additions for solid soluti on strengthening (i.e., W, Nb, and later Ta)4 could be used due to the vacuum atmosphere in the processing stage. Therefore better strength and creep resistance, and ultimately higher temperature capability, were realized in the resulting alloys. One of the first superalloys was Ni-20Cr, a simple solid solution strengthened alloy. To increase the strength of this all oy, metallurgists began to add other alloying elements, like Mo and C, to the Ni-Cr base alloy. The demand for higher temperature use was still present, and since Cr depressed th e Ni melting point, other alloying elements such as Al had to be utilized. The Ni-Al al loys worked well with the VIM process due to the reactivity of Al with the atmosphere and the need to keep Al in solution. There were two potential precip itate strengthening phases that could be used for the nickel-aluminum alloys: -NiAl, and -Ni3Al. Initially, the Ni-bas e alloys were single

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4 phase due to the FCC lattice which provided g ood creep resistance. It was later found that a matrix with ( is an order phase with an L12 type structure) precipitates produced higher strength materials and allo wed operational temperatures to increase further. The phase forms as a cuboidal precipitate but the shape of the precipitate is governed by the misfit strains betwee n the precipitates and the matrix.6 Negative misfit produces small cubes, and positive misfit produces spheres. A significant portion of the strengthening of the alloys is from the phase, the interface, and single coherent with the matrix. The aluminum also result ed in the formation of a thin Al2O3 coating on the surface which reduced the problems of co rrosion in the hot sections. The resulting alloys were the first generation superalloys. Al l of the elements that had previously been added to the matrix when steels and other meta ls were used (i.e., Cr, W, Nb, Ti, Ta, etc.), were all added to these new alloys. The resu lting Ni-based alloys could be used up to about 85% of their homologous temperature.4 The entire time alloy development was in progress, the processing advances were also occurring. Due to the high temperatures, turbine blades must al so withstand creep; a slow time-temperature-stress dependant type of deformation. Inve stigation found that creep life could be extended by reducing th e number of transverse grain boundaries within the component. The number of tr ansverse grains was reduced with the development of directiona l solidification in 1960.6 Directional solidification (DS) itself was further developed by controlling the with drawal rate of the casting, and therefore controlling the solidific ation front to yield only high angle boundaries (HAB) and low angle boundaries (LAB)7 along the direction of grain growth.

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5 DS work was not the last of the advancem ents in processing. The ultimate goal of DS was the complete elimination of grain boundaries from the cast component, to produce a single crystal. This was accomplis hed with the addition of a grain selector.8 This grain selector almost completely elim inates the HABs and LABs from the casting and produces a single crystal (SX). SX technology further in creased the operating temperatures and operational lifetimes of components within a turbine. The next key innovation was the addition of rhenium to the alloy. With the addition of 1 atomic percent (at%) Re, ther e was a substantial boost in the mechanical properties of the cast alloys. These alloys containing 1 at% Re became known as second generation superalloys. It is often said that Nece ssity is the mother of inven tion, and the desire for better operational capabilities of turbines was stil l the quest. Around the mid 1990s another 1 at% of Re was added to the superalloys.9 These were given the moniker of third generation superalloys due to their Re addition, which resulted in a further increase in the properties of the alloy. Throughout these all oy and process improvements, engineers and designers took advantage of the increased te mperature capabilities of the blade and vane alloys. Due to the increased temperature capab ilities of the materials, engine design has taken off more. The F-119 turbojet engine is currently the state of the art and generates 35000 pounds of thrust (Figure 3).10 A very large increase when compared to that of the early Jumo 004B (an increase of about 18 x in only 50 years). Due to the increased additions of many high density refractory elements (nearly 20% of the weight was due to less than 10% of the additions), a relatively minor problem began to becomes more significant. Unde sirable phases began to form in the

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6 Figure 1-3: A modern day turb ojet engine. This is the F-119 engine developed by Pratt & Whitney for the F-22 Raptor and the F-35 Joint Strike fighter. microstructure along specific orientations. These phases are called topologically close packed (TCP) phases. While they did form in the earlier generation superalloys, TCP has become more of a problem in the third gene ration superalloys. TCPs form at relatively high temperature, over extended time, consists primarily of the heavy refractory elements, and form within the microstructure of components in service. There are cases of TCP forming upon casting (i.e. CMSX-10), but these TCP phases can be put back into solution by solutioning heat treatments. Some of these solutioning heat treatments are exceedingly long and take over fifty hours11 to complete. TCP are composed of many of the refractory elements added to the alloy for strengthening, and the presence of the TCP therefore depletes the microstructure of th e key solid solution strengthening elements. Also, TCP are inherently brittle and are reported to be comm on failure initiation sites in failed components.4 TCP are needlelike in shape when viewed in the transverse di rection and disk like when observed from the proper longitudina l orientation. Some of the common TCP phases are , r, p, and Laves phases.12 Although relatively little is understood about TCP formation, an understanding of the elemen tal partitioning during solidification could

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7 aid in TCP prediction, alloy developmen t, and develop better heat treatment requirements. Earlier analysis involved the use of a segregation partitioning coefficient, k. This partitioning coefficient relates the difference in the amount of an element present between the dendrite core and the interdendr itic region and has been defined as13 itic Interdendr i Dendrite ix x k, ,' (equation 1-1) where xi, dendrite is the composition in the dendrite core (in wt%) for element i, and xi, interdendritic is the composition of element i within th e interdendritic region (in wt%). Other work has utilized partitioning coefficients by performing a Scheil analysis on the data collected. It is the goal of this investigation to fu rther examine the elemental partitioning that takes place during the solidification of a supera lloy. To do this a different technique was used to collect the data in the effort to determine how composition effects elemental segregation. This different technique was then compared against prior work done, and was re-examined to identify any new trends. Two additional checks were also done. The first was Scheil-type analysis that was preformed on one of the model alloys to s ee how the data collecti on technique in this study compared to that typically preformed in industry. The second check done in this investigation was then preformed on a co mmon, commercial superalloy to determine how the analysis used in this study compares to what is reported in open literature. Using the compositional data collected, this new analys is technique which used the curvature of compositional profile of the elemental segregation from dendrite core to dendrite core. This was be done in hope s of developing a better understanding of

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8 elemental segregation in a s uperalloy on solidification in or der to develop more castable alloys with reduced heat treatment requireme nts, and create new and better alloys for future use.

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9 CHAPTER 2 LITERATURE SEARCH Ni-base superalloys are some of the most complex metal alloys used, and are used in very extreme, if not hostile environments The metallurgy of superalloys begins with the microstructure that results from th e elemental additions, and then casting and processing. The processing of these advanced alloys has to be carefully controlled and the steps understood to produ ce the optimal balance of pr operties and to avoid the formation deleterious phases and an i nhomogeneous microstructure. There are inhomogentities in the elemental distribution that occur on casting of the advanced superalloys due to elemental partitioning and segregation. This section will provide an overview of this history and present current ideas regarding the phenomena of segregation in third gene ration Ni-base superalloys. 2.1. Evolution of Nickel Based Superalloys The development of Ni-base superalloys begins nearly 100 years ago. A simple wrought Ni-20Cr alloy was used for electri cal heating elements. They have grown tremendously from this humble beginning and have spread in their use from heating elements, to corrosion resistant alloys, and to high temperature applications. A specific high temperature application for Ni-base alloys is the hot section components of aircraft turbine engines, and industrial gas turbine (IGT) engines. The Ni alloys developed for use in these components need to have excel lent strength, creep re sistance, and fatigue resistance at high temperature, and also be resistant to oxidation and hot corrosion. The

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10 development of these alloys requires unique alloying additions and special casting and processing techniques. 2.1.1. The Matrix The ability for Ni-based superalloys to tolerate high levels of alloying without forming microstructural instabil ities, and to form the unique microstructure produces a material with unique properties. The material is composed of two phases, a matrix with precipitates spread throughout, with a coherent interface between the phases (Figure 2-1). Figure 2-2 is the Al-Ni phase diagram show ing the specific composition range of interest for the formation of these alloys.14 The matrix is a FCC structure and the is an L12 type ordered structure (Figure 2-3) The FCC structure exhibits the highest degree of packing with numerous sl ip systems which typically results in a material that maintains arrangement for c onstituent atoms to maintain tensile, creep rupture, and fatigue strengt h, at temperatures close to the homologous temperature. Figure 2-1: The matrix from model alloy LMSX-15. Image taken at 10kx. matrix and precipitates are labeled. matrix precipitate

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11 The FCC lattice also has a large range of solubili ty for other elements that can be used to improve the properties of the alloy. The precipitate has nearly the same lattice parameter as the matrix making the matrix and precipitate coherent. Figure 2-2: Al-Ni phase diagram. The AlNi3 field is visible at 85 87 wt% Ni. Figure 2-3: FCC matrix shown above left and L12 ordered phase of Ni3Al (Ni shown in black) above right.6 The benefits of the FCC or matrix were originally discovered in steels and were found to have the ability to be heavily alloyed. The base element for high temperature alloys was shifted from Fe to Ni and Co becau se they had the ability to be alloyed to a greater extent and the microstructure could be formed. Cr and Al were some of the

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12 earliest additions to this base material. They acted as solid solution strengtheners, increased environmental resistance, and incr eased the high temperature properties of the alloys. The addition of Cr to the matrix incr eased the alloys resist ance to hot corrosion, and Al increased its resistance to high temperature oxidation.4,6 The high strength of the superalloys come s from solid soluti on strengthening, precipitation hardening, a nd the misfit between the and its coherent ordered precipitated, . When alloying elements are ad ded, the lattice parameters for the and both change slightly due to the alloying elem ents being larger or smaller than the one they are substituting for (Hume-Rothery criteri a for solid solution strengthening). The misfit is the difference in lattice parameters between the matrix and the precipitate. Misfit influences the shape of the precipitate. At low misf it strains (0.0 0.2 %), the precipitates are spherical. At sligh tly higher misfit stra ins (0.5-1.0 %), the precipitates are cuboidal. Finally, when the mi sfit is even higher (> 1.25 %), the precipitates are plate-like. It is the formation of the cuboidal and the very fine (secondary) (which is formed on ageing) that prevents dislocation bypass and forces the dislocations to cut through the ordered particle forming a superdislocation. The volume fraction is also important because it influences alloy strength4. Alloys that have a very high volume fraction ( 70% and greater) exhibit high strengt h, but very limited ductility, and the opposite is true for the low volume fraction alloys. It is the combination of the volume fraction, misfit, and coherency of the precipitate that bring about th e high strengths of superalloys. There are many different elemental additi ons used to improve the properties of superalloys. Among the additions are Co, Cr, Mo, W, Re, Ta, Ti, Ru, and Pd (which has

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13 become of recent interest). Many of these elements are soluble in the Ni3Al system (Figure 2-4).30 Each addition has various contributions it provides to the superalloy as a whole, and summarized below Cobalt Added to reduce or offset the solvus temperatur e without causing incipient melting4,6,15, is reported to increase the mi crostructural stability of the alloy9,15, reduces stacking fault energy ( SFE), and provides some solid solution strengthening.6 Co has been reported to pa rtition to the dendrite core.16,17,18 Chromium : Added to increase the surface stability and prevent/minimize hot corrosion4,6, reduces the solvus temperature19, reduces the anti-phase boundary energy ( APB) of the phase. Cr has been to partition to the dendrite core16,17,18 and is a known component of TCP phases.4,6 Molybdenum : Added to increase solid solution strengthening of the matrix6,18, lower the alloy density (Mo is less dense than other elements like W), adjust the volume fraction.20 Mo has been reported to partition to the dendrite core16,18,21, and is a known component of TCP phases.4,6,12 Tungsten : Added because it is a potent solid solution st rengthener in Ni-base alloys16,18, and W increases the inci pient melting point of the alloy. W partitions to the dendrite core and is a known component of TCP phases.6,12 W has also been reported to increase the susceptibil ity of the alloy to hot corrosion. Rhenium : is the element that defines the diffe rence in superalloy generations. It is a strong solid solution strengthener22, and increases the high temperature creep properties.18 Re is an element found in TCP phases23 and partitions to the dendrite core.17,19,25 Tantalum : like Re is a strong so lid solution strengthener.18,25 Ta is also added to improve castability26, increase the volume fraction15, decreases the susceptibility to incipient melting27, increase the anti-ph ase boundary energy ( APB) of the , and is one of the formers. Ta has been reported to partition to the interdendritic region.16,18,22 Aluminum : is the primary former.4,6 Al is also added to increase surface stability and high temperat ure oxidation resistance4,6, and Al improves the castability of the alloy. Al has been re ported to partition to the interdendritic region.16,18,22 Titanium : another former.4,6 Ti is less dense than Ta, it increases the volume fraction15, increase the anti-ph ase boundary energy ( APB) of the , and strengthens the phase.4,6,16 Ti has been reported to par tition to the interdendritic region.16,18

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14 Ruthenium : is reported to increase the microstructural stability28 and act as a solid solution strengthener. Ru has been re ported to partition to the dendrite core.16,29 Palladium : is an element of recent investiga tion. Pd is added to improve the surface stability of th e alloy and act as a solid solution strengthener. Pd has been reported to partition to the dendrite core.16,29 There are other trace elements (i.e. Hf, and B) that are added as well as many deleterious elements (i.e. Cd, Hg, O, and N) that have to be removed by meticulous quality control and specializ ed processing procedures. Figure 2-4: Ni-Al-X ternar y phase diagram. The Ni3Al phase fields are shown in the phase diagram with the various other additions, indicating large regions of solubility. 2.1.2. Casting and Specialized Processing Techniques The original superalloys we re cast using investment cas ting techniques from dental prosthesis.6 Investment casting involves the pouring of the molten alloy into a preformed shell mold and then breaking the she ll mold away from the components after the alloy has solidified and coole d. This left behind grains of various sizes throughout the alloy due to different localized cooling rates. In some instan ces, inclusions were left in

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15 the casting from the shell, impurities in the metal melted, or some of the alloying elements oxidizing before the all oy solidifies (i.e. 2 Al + 3/2 O2 Al2O3). For the properties of the superalloys to increase, these problems had to be overcome. Vacuum induction melting (VIM) overcame these problems. Developed in the 1950s by Falih N. Darmara6, VIM removed the atmosphere to keep the reactive elements (i.e. Al and Ti) from oxidizing and leaving inclusions in the cast alloys, and aided in removing of some of the deleterious tramp elements from the alloys. VIM also allowed for closer control of the elemen tal additions. The mechanical properties increased after VAR was used. (Figure 2-5).4 Figure 2-5: The improvements in alloy elonga tion and rupture strength for the same alloys (M-252 and Waspalloy) for vacuum melt and air melt. Superalloy properties were increased with the advent of VIM and VAR, but another advancement had to achieved to continue to increase the useful temperatures and mechanical properties as turbine inlet temperat ures continued to rise. The presence of transverse grain boundaries was reduced with th e use of directional solidification (DS). The DS process was initially developed in the 1960s by F. VerSnyder and colleges working at Pratt & Whitney.6 The process used was then further improved upon by G. Chadley working at TRW.7 The improvement involved a controlled withdrawal of the casting from the furnace. The grains nucleate on the chill plate and grow into the melt,

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16 but the solidification interface does not change location relative to the outside of the furnace. The solidification interfaces only move s relative to the component as it is being cast. By controlling the w ithdrawal rate, which controlle d the solidification front, the only grains formed in the casting are onl y high angle boundaries (HAB) and low angle boundaries (LAB). The removal of transverse grain boundari es dramatically increased the creep properties of the alloys. The next goal wa s the elimination of grain boundaries from the alloy entirely. B. Piearch modified the mo lds being used for DS. He added a grain selector to the lower part of the casting. Th is grain selector was designed to let only on grain orientation through. This is typically the <001> orientation due to its high creep rupture properties. When the alloy was now cast, it was a single crystal (SX) with no longitudinal or transverse grains. Figure 2-631 shows the configura tion for DS casting techniques and Figure 2-731 shows the configuration for SX casting techniques. As the superalloys were being cast, they began to develop a problem. A metastable phase would develop in the microstructure ov er time while the alloy was in-service or on casting due to the high refractory element c ontent. These phases are the topologically close packed (TCP) phases and they deplete th e matrix of alloying elements when they are formed from the constituent alloying elements.12 TCP are thought to be fracture initiation sites due to their shape and brit tle behavior. Methods like PHACOMP were developed to create alloys that had stable mi crostructures that were stable (i.e., were not

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17 Figure 2-6: DS casting oper ation is shown on the left and SX casting operations are shown on the right. The primary differen ce is the use of a c onstrictor or single crystal selector. prone to form TCP phases). As more and mo re refractory elements were added to the alloy, the frequency of TCP formation increa sed. TCP formation was noted in some of the early superalloys during service life, but in alloys like CMSX-10, TCP phases form on casting due to the high refractory element content. Solutioning heat treatments are done to remove the TCP phases from the as-cas t alloys but these heat treatments are very long (upwards of 50 hours), at high temp erature (CMSX-10 is solution heat treated at temperatures above 1350C).16 There are several different TCP phases found in superalloys. Among these are , p, r, and the Laves phases. and p are composed predominately of Ni Cr, and Re, and to a lesser extent Co, W, and Mo.12 When a SX component is cast, a solidificati on front is formed as the dendrites grow into the melt. The dendrites reject certai n elements back into the liquid depending up how the elements partition. This rejection is the origin of the segr egation of the alloying elements within the microstructure. With the elements not being homogeneously distributed in the alloy, solutioning heat treatments must be preformed.

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18 Solutioning heat treatments (solutioning fo r short) are done at temperatures above the solvus temperatures and below the solidus temperature and at times sufficient to have the elements become evenly distribute d. The difference in these two temperatures ( solvus and solidus temp eratures) is called the window. In general, alloys that have less segregation are more easily solutioned. There are several benefits to developing a better understanding of the segregation of the constituent elements in a nickel base superalloy. By understanding which elements segregate more strongly, solution heat treatme nts can be developed that are potentially shorter and at lower temperature. The deve lopment of new alloys would also benefit from this understanding, by using elements th at have been shown to reduce segregation, and therefore, reduce TCP formation.

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19 CHAPTER 3 MATERIALS AND EXPERIMENTAL PROCEDURE In this chapter, the materials and proc edure that were used in this study are described along with the various t echniques used to analyze them. 3.1. Materials The materials used are based on a thir d generation Ni-based superalloy. The baseline alloy (LMSX-1); has a composition in weight percent (wt% ) of Ni-bal, Cr-4.15, Co-12.2, W-5.85, Re-5.9, Ta-8.6 Al5.5, Hf-0.1. The baseline composition is related to CMSX-10 and Ren N6, both being third gene ration superalloys. From this LMSX-1 baseline alloy, 17 other model alloys were de signed to evaluate the effect of typical alloying additions on the solid ification behavior and prope rties of Ni-base superalloy single crystals (Table 3-1). The elemen tal additions and the compositional ranges selected were based on industrial experience, material development history, and current industrial trends. The 17 model alloys each had one to two vari ations from the baseline alloy so that the influence of each type of addition could be examined. LMSX-2 and -3 were added to study the influence of cobalt on stability, solvus and solid solution strengthening. LMSX-2 contained a moderate level of Co (8 w/o) and LMSX-3 contained a low level (4 w/o Co). Note that LMSX-1 has 12 wt% Co which is similar to the Co concentration in Ren N625, and LMSX-3 has 4 wt% Co for comparison to CMSX-10.9 Ren N6 was developed by GE, and CMSX-10 was developed by Cannon-Muskegon. These manufacturers have different id eas as to the effects of Co.9,25,31 LMSX-4 and -5 have

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20 variations in the amount of chromium present in these a lloys. These alloys were developed to examine the effect of Cr content on microstructure stability, solvus temperature, and surface stability. LMSX-4 has a high Cr level (6.15 w/o) and LMSX-5 contains a low level (2.1 w/o) of Cr. LMSX-6 has a high level of tungsten (8.6 w/o) to investigate tungstens effect on stability and solid solution strengthening. LMSX-7 and 8 both have a 1 a/o (1.6 w/o) addition of molybdenum, to de termine the effect of Mo additions on stability and solid solution st rengthening. LMSX-7 substituted 1 atomic percent (at%) Mo for 1 at% W, so the alloy contained a reduced amount of tungsten (3.1 w/o). LMSX-9, -10, and -11 all have varyi ng amounts of rhenium. LMSX-9 contains no rhenium (0 w/o). LMSX-10 contains a lo w level of rhenium (1 at% or 2.95 wt%). LMSX-11 has the largest amount of rhenium of all the alloys (3at% or 8.7 w/o). These alloys are intended to cover wh at is essentially the first th ree generations of superalloy (LMSX-9, -10, and -1) to determine the effect of the Re on stability of first, second, and third generation superalloys. The high Re c ontent in LMSX-11 was added to investigate the stability of alloys with large Re a dditions. In LMSX-12, -13, -14, and -15, the amounts of the formers, Al and Ta, were varied from alloy to alloy and titanium was substituted in the latter two. LMSX-12 and -13 have changes in the amounts of Ta and Al to determine the effect of Ta/Al ratio va riations on solvus and solidus temperatures, elemental solidifica tion segregation, and size and shape. In LMSX-14 and -15, Ti was substituted for Ta (in LMSX-14) or Al (LMSX15) to determine if Ti affected the alloys solidus, solvus, segregation, and strength. Th e alloys LMSX-12, -13, -14, and -15 were all intended to have a constant volume fraction. To begin examination of the fourth generation superalloys, LMSX-16 and -17 both have additions of ruthenium (1.6 and 3.2

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21 w/o respectively). It has been reported th at Ru additions affect stability and solid solution strengthening28 and these two alloy were added to investigate that claim. LMSX-18 has a 1 a/o addition of palladium ( 1.7 w/o). Pd, a member of the precious metal group (i.e. Re, Ru, Pd, Pt, Au) was also included in this study since it has also been reported to affect microstructural st ability, strength, and surface stability.32,33 The alloys were cast in si ngle crystal bars at Precisi on Cast Components Airfoils (PCC Airfoils, Minerva, OH). A commercial directional solidification furnace was used with high gradient investment casting techniques to cast the a lloys in a [001] orientation. An inchworm type grain selector was used to produce single cr ystal samples. The withdrawal rate was initially set at 6 in (15.24 cm) per hour until the grain selector was reached. After that point, the rate was ch anged to 8 in (20.32 cm) per hour. The bars were cast in cylinders with a diameter of 1.25 cm and a length of 20 cm. One mold was processed for each alloy, and each mold contai ned nineteen bars. Af ter casting, the [001] orientation was verified by Laue backscattered x-ray technique s. For the purpose of this investigation, samples with defects such as freckles, slivers, high angle boundaries (HAB), and low angle boundaries (LAB) were not used. 3.2. Metallography After receipt of the bars, specimens were sectioned for metallographic evaluation. A LECO CM-20 cut-off wheel, using a LEC O 3025 blade (rated for HRC 45-60) was used to perform all sectioning of the bars. The bar was cut in the middle, and starting from the cut mid-section ends, another cut was made to leave behind a small disk 1.25 cm in diameter and 0.5 cm thick. This disk was then sectioned in half to produce two semi-circular specimens for micr ostructural characterization.

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22Table 3-1: Compositions of the 18 model alloys in weight percent (wt%). Highlighted regions indicate change s made from baselin e. Compositions of Ren N6 and CMSX-10 shown for comparison. Alloy ID Ni Cr Co Mo W Ta Re Al Ti Hf Ru Pd Comments LMSX-1 Bal 4.10 12.20 5.85 8.60 5.90 5.55 0.10 Baseline 61.95 5.00 13.00 2.00 3.00 2.00 13.00 0.05 Atomic % Composition LMSX-2 Bal 4.10 8.00 5.85 8.60 5.90 5.55 0.10 Reduced Co (8 at%) LMSX-3 Bal 4.10 4.00 5.85 8.60 5.90 5.55 0.10 Minimum Co (4 at%) LMSX-4 Bal 6.15 12.20 5.85 8.60 5.90 5.55 0.10 High Cr (7 at%) LMSX-5 Bal 2.10 12.20 5.85 8.60 5.90 5.55 0.10 Low Cr (3 at%) LMSX-6 Bal 4.10 12.20 8.60 8.60 5.90 5.55 0.10 High W (3 at%) LMSX-7 Bal 4.10 12.20 1.60 3.10 8.60 5.90 5.55 0.10 Low W (1 at%) + 1 at% Mo LMSX-8 Bal 4.10 12.20 1.60 5.85 8.60 5.90 5.55 0.10 +1 at% Mo LMSX-9 Bal 4.10 12.20 5.85 8.60 0.00 5.55 0.10 0 at% Re LMSX-10 Bal 4.10 12.20 5.85 8.60 2.95 5.55 0.10 1 at% Re LMSX-11 Bal 4.10 12.20 5.85 8.60 8.70 5.55 0.10 3 at% Re LMSX-12 Bal 4.10 12.20 5.85 11.20 5.90 5.00 0.10 High Ta (4at%), Low Al (12 at%) LMSX-13 Bal 4.10 12.20 5.85 6.00 5.90 6.15 0.10 Low Ta (2 at%), High Al (14 at%) LMSX-14 Bal 4.10 12.20 5.85 6.00 5.90 5.65 0.80 0.10 Low Ta (2 at%) + 1at %Ti LMSX-15 Bal 4.10 12.20 5.85 8.60 5.90 5.10 0.80 0.10 Low Al (12 at%) + 1 at% Ti LMSX-16 Bal 4.10 12.20 5.85 8.60 5.90 5.55 0.10 1.60 +1 at% Ru LMSX-17 Bal 4.10 12.20 5.85 8.60 5.90 5.55 0.10 3.20 +2 at% Ru LMSX-18 Bal 4.10 12.20 5.85 8.60 5.90 5.55 0.10 1.70 +1 at% Pd CMSX-10 Bal 3.00 4.00 0.60 6.00 8.00 6.00 5.75 0.10 Rene N6 Bal 4.50 12.50 1.10 5.75 7.50 6.00 5.35 0.15

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23 Once the specimens were cut, they were m ounted using a LECO PR-10 mounting press. The specimens were mounted in 3.175 cm ( 1.25 inch) mounts using di allyl phthalate and labeled as LMSXX as cast where X indicated the specifi c alloy identification number. With the metallographic specimens mounte d, they were then leveled, ground, and polished to a mirror-like finish. The leve ling of the specimens was done using a LECO BG-20 belt grinder with a water cooled 240 grit belt. The edges of the specimen mounts were first chamfered to ease handlin g and lessen hydroplaning during polishing. Leveling was done until there was no diallyl phthalate covering the specimen and there were no raised spots obvious on the sample. All of the grinding and polishing was done using a LECO VP-20 Vari/Pol, operated at 300 rpm, and water was used to lubri cate and cool the specimen. Standard metallographic practices for grinding and po lishing were used to prepare the specimen33, and a Branson 1200 ultrasonic sink was used for ultrasonic cleaning of the specimens between polishing steps. Two techniques were evaluated for grindi ng and polishing. The first technique was considered the standard technique, which ha s been typically used by the University of Florida Materials Science and Engineering De partment, and the second was an advanced technique initially develope d by Struers Inc and further modified for this study. The standard technique was done on LMSX1, -2, -3, -4, -5, -9, -10, -11, -16, -17, and -18. Grinding was done using wet-dry al umina grinding disks beginning with 240 grit, followed with 320, 400, 600, and finally 800 grit. This was followed with two rough polishing steps. Rough polishing was done using 20.32 cm (8 in) billiard cloths with first 15 m and then 5 m alumina suspended in water. Fine polishing was done using LECO

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24 Micron cloths with first 1 m and then 0.3 m alumina suspended in water. All specimens were polished to a mirror-like fini sh and examined optic ally for scratches. The advanced technique was done on LMSX -6, -7, -8, -12, -13, -14, and -15. The grinding steps were done using Struers MD-Piano 600 and MD-Piano 1200 grit magnetic grinding disks. The particulate was imbedded into the disk itself and only needed to be dressed between specimens to maintain the proper grit size. Rough polishing was done using a Struers MD-Mol magne tic disk with the appropria te MD-mol solution. This solution was water based and needed either l ittle or no extra water for lubrication. The final polishing was done in the same manne r as the standard technique. Again, all specimens were polished to a mirror-like fini sh and examined optic ally for scratches. Although no specimen was done using both t echniques, the final requirement was the same: a mirror-like finish without scratches. This was easily attainable with both techniques given sufficient time. The adva nced technique, using the magnetic disks, offered reduced grinding and polishing times, less mess, fewer steps, and a decreased chance of cross contamination between grit sizes. The advanced technique has the setback of increased time if a step is not done properly due to the large changes in grit sizes used. If done correctly, specimen preparation time was reduced from 45 min to 20 min. 3.3. Scanning Electron Microscopy/ Backscatter Electron Microscopy Electron microscopy was first done usi ng a JOEL SEM 6400. The instrument was operated with an accelerating voltage of 15 keV and a working distance of 15 mm. The instrument was primarily operated in the b ackscattered mode. Using the backscattered electron (BSE) imaging, 20 images were taken of each specimen in the ascast condition.

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25 The images were taken in a grid like manne r of four-by-five. The images were 1 mm apart in the y direction and 2 mm apart in the x directio n. These images were taken to calculate the primary dendrite arm spacing (PDAS). Figures 3-1 and 3-2 are representative of the BSE images taken to determine the PDAS. Appendix A contains additional images from this portion of this investigation. Figure 3-1: BSE image of LMSX -1 taken at 100x equivalent. Figure 3-2: BSE image of LMSX -13 taken at 100x equivalent X Y X Y

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26 3.3.1. Electron Microprobe Analysis The remainder of this investigation of the segregation behavior of these alloys was done using electron microprobe analysis (E MPA). The instrument used for this examination was a JOEL 733 Superprobe. The instrument was operated with an accelerating voltage was 15 keV, a take -off angle of 40, a spot size of 1 m and a beam current 20 nA. Each point in the EM PA was measured by wavelength dispersive spectroscopy (WDS) and measur ed for 10 seconds per point. Specific calibration for Ni, Cr, Co, Mo, W, Re, Ta, Al, Ti, Ru, Pd, and Hf were all used as references. To expedited the sca nning times, as many different crystals as possible were used while maintaining the best line (K L or M ) to scan. A LiF crystal was used to measure intensities for Ni, Cr, and Co. The compositional analysis for these elements was based on the K lines. To measure intens ities for W, Re, Ta, Hf, and Al, a TAP crystal was used. To determin e the chemical analysis of these elements, the K line for Al was measured, and the L lines were used for all the others on this crystal. Finally, a PET crystal was used to measure intensities for Ru, Mo, and Ti, with chemical composition based on the K line for Ti and the L lines for Ru and Mo. A small computer routine for the microprobe had to be used to perform the line scans, along with some of the proper settings. Due to the ag e of the equipment, some of the line scan routines had to be varied to detect specific elements. These routines are found in Appendix B. A problem occurred with measuring some of the trace elements due to the age of the software. The trace elements of Mo in LMSX-7 and -8, Ti in LMSX -14 and -15, and

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27 the Ru in LMSX-16 all required a specific step to be added to this routine to properly measure the peak. Line scans were used to measure co mposition and segregation within the microstructure. A line of 30 points was s canned running between two dendrite cores through the interdendritic region. Care was taken to avoid any secondary and tertiary dendrite arms. Image 3-3 contains an exampl e of one of the line scans examined. The typical length of each line scan was 300 m. Three scans were done on each specimen and all the data was entered by hand, again due to the age of the equipment. A total of 90 points were scanned for each specimen. This technique is a variation of that used by Pollock et. al.34 The technique to measure/quantify solidif ication segregation was developed by M. N. Gungor36 and is commonly found to be the indus try standard. This technique involves a grid of point scans across the specimen, all equally spaced. To check the validity of the new method of using line scans, the grid me thod was used on LMSX-3. The PDAS of Figure 3-3: BSE photo of LMSX-1 taken at 100x equivalent. Yellow line indicates location of the line scan preformed.

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28 LMSX-3 was measured at 253.4 m and a slightly larger spacing of 265.0 m was used for the spacings between points in the line scans. Fifteen line scans of fifteen points were used with the larger spacings used for a total of 225 points scanned.11 This atomic percent and normalized weight percent data we re then entered into a spreadsheet by hand for analysis. 3.3.2. Verification of App licability of Analysis To provide an independent check of this investigation, a piece of as-cast CMSX-4 was sectioned, mounted, and polished (using th e standard technique) to an optically verified mirror like finish. CMXS-4 was used due to availability of the as-cast sample. The composition of CMXS-4 is listed in Ta ble 3-2. The EMPA was preformed in a similar fashion to that described above to see if the techniques described above were applicable to current production alloys and to broaden the possible spectrum of further understanding of trends f ound in this experiment. Table 3-2: Composition of CMSX-4 in wt%.4,6 Alloy ID Ni Cr Co Mo W Ta Re Al Ti Hf CMXS-4 Bal 6.5 9.0 0.6 6.0 6.5 3.0 5.6 1.0 0.10

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29 CHAPTER 4 EXPERIMENTAL RESULTS For clarity, the results of this investigation are broken down into three parts. First, the primary dendrite arm spacing (PDAS) will be discussed. Then the observations of the electron microprobe analysis are evaluated. Finally, the two electron microprobe analysis techniques will be compared and evaluative. 4.1. Primary Dendrite Arm Spacing Twenty 100x images (or fields of view) ta ken of each of the 18 model alloys were used to calculate the primary dendrite arm spacing (PDAS). Due to the natural variabilities in dendrite arm spacings, from 6 to 8 measurements were taken from each field of view, but the number was held consiste nt for all fields for that alloy. Figure 4-1 is one of the 100x BSE images from LMSX-12. The black lines drawn on the image are examples of the lines used to measure the PDAS. This procedure was repeated for all twenty fields of view, and then the final values were tabulated. To make measuring easier, the micron bar on the image was meas ured and used as a standard. It was measured at 5.4 cm and indicated 500 m long. This allowed a machinists scale to be used to make all the measurements directly fr om the field of view and then ratioed back to the actual size. The average, standa rd deviation, and median values were all calculated. Table 4-1 contains the results from these calculations. This was done to develop an understanding of the accuracy in calculating the PDAS from the EMPA line scans.

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30 All of the measured PDAS standard deviat ions were relatively large, and all but two of the PDAS measurements fell to within one standard deviation of the mean. The exceptions were LMSX-10 and -17. Of the rema ining sixteen alloys, six of the measured PDAS were very close (about 20 m difference) to those calculat ed from the line scans. Another eight of the measurements were within about 50 m of one another. The only alloys that exhibite d a variation in PDAS greater than 70 m (other than LMSX-10 and17) were LMSX-1 and -2. LMSX-1 had the hi ghest standard devia tion for PDAS of the eighteen alloys. Figure 4-1: BSE image of LM SX-13. Black lines added to image were where PDAS measurements were taken. 4.2. Electron Microprobe Analysis To quantify and characterize the inho mogeneties and segr egation in the microstructure that occur during solidifi cation, a lengthy analysis was preformed to develop a better understanding of the elemental interactions an d solidification behavior. The electron microprobe analysis (EMPA) resu lts are broken down into three sections. The first section contains the results of the lin e scan technique and how they relate to the

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31 Table 4-1: PDAS measurements from EMPA and from hand calculations. Standard deviation is shown for hand calcula tions. All measurements are in m. LMSX1 2 3 4 5 6 7 8 9 EMPA 287.66 267.39 250.94 259.61262.91 225.52307.24 262.31367.90 Measured 374.33 343.00 253.47 294.35310.84 281.65331.78 320.62 381.86 St Dev 104.1 98.7 64.3 84.0 87.1 97.5 80.7 74.1 84.5 LMSX10 11 12 13 14 15 16 17 18 EMPA 271.41 223.59 275.72 257.35226.80 290.93247.51 174.70258.09 Measured 360.23 258.52 325.85 280.03281.48 286.40284.51 268.91271.53 St Dev 116.1 61.0 79.5 79.8 72.4 78.2 61.7 79.9 70.1 elemental segregation and partitioning for the eighteen model alloys. The next section contains the results from the grid scan of LMSX-3. Finally, the da ta from the line scans from CMSX-4 are presented. The data was measured in atomic percent (at%) and then converted to normalized weight percent (wt%) and recorded. Within these eighteen model alloys, a total of fifteen relationships were observed. Eight of these relationships could be directly related to the variation of a single elemental addition. The remaining seven show the interac tions that appear to be present from alloy to alloy based on the variation of only two el ements (i.e. Ta and Al both varied from baseline). The relationships observed that re late to elemental variations are as follows: Cobalt. By comparing LMSX-1, -2, and -3. Chromium. By comparing LMSX-1, -5, and -5. Rhenium. By comparing LMSX-1, -9, -10, and -11. Ruthenium. By comparing LMSX-1, -16, and -17. Tungsten. By comparing LMSX-1 and 6. Molybdenum. By comparing LMSX-1 and -8 Palladium. By comparing LMSX-1 and -18. Tungsten with a Molybdenum addition. By comparing LMSX-7 and -8. The remaining relationships that were observed were examined to qualify the interactions that might be present in the systems where two elemental additions were varied. These systems are listed as follows:

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32 Variation of Tantalum and Aluminum from the baseline. LMSX-1, -12, and LMSX-1, -13. Variation between Tantalum and Aluminum. LMSX-12 and -13. Variation of Tantalum and Aluminum fr om the baseline with an addition of Titanium. LMSX-1, -14, and LMSX-1, -15. Variation between Tantalum and Aluminum with an addition of Titanium. LMSX14 and -15. Variation between decreasing Tungsten a nd increasing Molybde num. LMSX-1, -7 and -6, -8. As noted previously, all final data from the line scans is presented in normalized weight percent (wt%). 4.3. Elemental Segregation and Partitioning Three line scans from dendrite core to dendrite core through the interdendritic region were preformed on one specimen from each of the model alloys. The composition of each point along the line in each alloy was determined. The average values for each element for the three line scans for each speci men were calculated. Appendix C contains the average EMPA results for the eighteen model alloys. Nearly all the elements in all the alloys exhibit some degree of segreg ation; however the degree and direction (dendritic or interdendritic) of the segregation varied. A partitioning coefficient (k) was calculated from the average values of each element from the set of line scans from each alloy The partitioning coefficient parameter is indicative of the degree of segregation during solidification and tendency for an elemen t to segregate to either the dendrite core or the interdendritic re gion and how much upon casting. k is defined as itic Interdendr i Dendrite ix x k, ,' (Equation 1-1)

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33 where xi, dendrite is the composition (in wt%) at the dendrite core and xi, interdendritic is the composition (in wt%) roughly equidi stant between both dendrite cores.11, 16,36-40 The points chosen for the determination of the segregation partition coefficient came from either end of the line scan (i.e. the dendrite core). The interdendr itic value was chosen from either of the midpoint of this average scan, with one exception. When the minimum or maximum compositional level did not occur at the midpoint, this interdendritic value was taken from a trendline. If the mid points did not lie reasonably ne ar the trendline, the next point on the line was c hosen. This was done to avoid the possibility that the midpoints chosen would not indi cate the actual degree of segregation as shown by the trendlines of the actual data was as indicated. Table 4-2 contains the k values calculated from this method. Data listed as kA is the data collected by F. Fela.16 The partitioning coefficients calculated in th is study are reported as kB. A k less the unity indicates a tendency of this element to segregate to the interdendritic region; whereas a k greater than unity indicates segregation to the dendrite core.11,16,36-38 Graphs were then developed to show the variations of k as the composition was varied in this investiga tion. Figures 4-2, 4-3, and 4-4 graphically illustrates how kA and kB compared to one another for LMSX-1, -13, and -18 as examples. From the comparisons, it can be seen that although the segregati on behavior in both studies indicate similar direc tions of segregation, the magnit udes varied particularly for Re. The magnitude difference can be attribut ed to differences in the location used to measure composition within the specimen bei ng locally different from one another. However, it is clear that the segregation trends represented by k largely holds true for

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34 both kA and kB. The formers, Ni, Al, Ta, and Ti, all segregated to the interdendritic region, and the solid solution strengtheners, Cr, Co, W, and Re segregated to the dendritic region. Although the segregation be havior was similar in both studies, there was a discrepancy in the segregation behavi or of Mo in LMSX-8 (+ 1 at% Mo). kA indicated that Mo segregated to the dendritic region, whereas kB indicated Mo segregated to the interdendritic region. Fi gure 4-5 contains the graph that compares the results of both kA and kB. Figure 4-6 is the graph for LM SX-8 that was used to identify the points for the k partitioning analysis. The points chosen for the k analysis are shown as large open circles on the graphs. In addition, a second order trend line was plotted to aid in visualizing the segregation behavior. For comparison, a similar graph for Al from LMSX-1 and -18 is shown with the sa me data points used for calculation of k labeled as in Figure 4-7.

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35Table 4-2 Showing weight percentages of each respective element in each alloy from the dendrite core and the interdendritic reg ion, and the calculated k value for both tec hniques A (in orange), and B (in blue). Alloy Ni Cr Co Mo W Re Ta Al Ti Ru Pd Dendritic 56.044.0713.04 6.8310.494.864.33 Interdendritic 61.763.9311.40 4.313.3810.085.74 k'B 0.91 1.04 1.14 1.58 3.10 0.48 0.75 LMSX-1 k'A 0.93 1.11 1.12 1.79 3.060 0.490 0.74 Dendritic 59.964.279.04 6.7310.855.024.67 Interdendritic 63.853.567.64 4.293.5710.386.39 k'B 0.94 1.20 1.18 1.57 3.04 0.48 0.73 LMSX-2 k'A 0.91 1.64 1.29 1.93 5.940 0.430 0.71 Dendritic 64.903.914.33 6.7110.794.984.46 Interdendritic 69.003.663.52 3.582.2211.356.33 k'B 0.94 1.07 1.23 1.87 4.86 0.44 0.70 LMSX-3 k'A 0.95 1.07 1.13 1.78 3.110 0.500 0.76 Dendritic 54.876.3513.37 6.679.724.264.46 Interdendritic 59.166.0711.19 4.383.169.295.48 k'B 0.93 1.05 1.19 1.52 3.08 0.46 0.81 LMSX-4 k'A 0.93 1.16 1.10 1.70 3.020 0.480 0.80 Dendritic 60.752.5913.37 5.799.293.694.51 Interdendritic 64.882.6512.87 3.543.596.865.79 k'B 0.94 0.98 1.04 1.64 2.59 0.54 0.78 LMSX-5 k'A 0.94 1.18 1.14 1.68 3.050 0.520 0.76 Dendritic 57.174.6713.97 8.449.173.434.56 Interdendritic 61.764.5412.01 4.473.418.466.61 k'B 0.926 1.029 1.163 1.888 2.689 0.405 0.690 LMSX-6 k'A 0.89 1.41 1.21 2.00 4.590 0.390 0.68

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36Table 4-2 (Cont.) showing weight percentage s of each respective element in each alloy from the dendr ite core and the interdendr itic region, and the calculated k value A (in blue), and B (in orange). Alloy Ni Cr Co Mo W Re Ta Al Ti Ru Pd Dendritic 60.3 4.7413.651.612.888.64 3.974.72 Interdendritic 62.48 4.2912.891.822.043.67 7.375.65 k'B 0.97 1.10 1.06 0.88 1.41 2.35 0.54 0.84 LMSX7 k'A 0.95 1.20 1.22 1.08 1.36 3.300 0.500 0.79 Dendritic 57.75 4.4413.711.545.558.59 3.914.71 Interdendritic 61.5 4.312.971.883.813.47 7.755.56 k'B 0.94 1.03 1.06 0.82 1.46 2.48 0.50 0.85 LMSX8 k'A 0.88 1.79 1.45 1.48 2.00 5.660 0.380 0.64 Dendritic 64.35 3.7912.82 7.390 5.624.70 Interdendritic 63.79 3.7911.59 4.570 9.255.45 k'B 1.01 1.00 1.11 1.62 0.00 0.61 0.86 LMSX9 k'A 1.02 1.37 1.25 1.76 0.000 0.570 0.90 Dendritic 60.31 3.8313.53 6.915.69 5.324.60 Interdendritic 62.62 3.5911.38 4.321.67 10.655.53 k'B 0.96 1.07 1.19 1.60 3.41 0.50 0.83 LMSX10 k'A 0.97 1.01 1.14 1.62 3.280 0.500 0.85 Dendritic 54.30 4.6313.62 4.8213.81 3.294.40 Interdendritic 62.62 3.6110.92 2.792.06 9.796.80 k'B 0.87 1.28 1.25 1.73 6.70 0.34 0.65 LMSX11 k'A 0.88 1.13 1.18 1.83 3.74 0.40 0.69 Dendritic 57.53 4.4113.89 5.978.85 5.264.36 Interdendritic 61.26 3.9012.03 3.803.31 9.765.68 k'B 0.94 1.13 1.15 1.57 2.67 0.54 0.77 LMSX12 k'A 0.95 1.17 1.12 1.62 3.37 0.53 0.80

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37Table 4-2(Cont.) showing weight percentage s of each respective element in each alloy fr om the dendrite core and the interdendri tic region, and the calculated k value A (in blue), and B (in orange). Alloy Ni Cr Co Mo W Re Ta Al Ti Ru Pd Dendritic 59.494.1413.36 5.699.972.185.07 Interdendritic 67.134.6311.14 2.751.706.427.37 k'B 0.89 0.89 1.20 2.07 5.86 0.34 0.69 LMSX-13 k'A 0.89 1.10 1.18 2.08 2.86 0.39 0.73 Dendritic 61.754.7213.97 5.257.301.934.120.48 Interdendritic 66.523.9612.66 2.872.344.385.701.15 k'B 0.93 1.19 1.10 1.83 3.12 0.44 0.72 0.42 LMSX-14 k'A 0.88 1.55 1.32 2.65 10.49 0.34 0.68 0.29 Dendritic 58.234.3213.82 5.729.663.584.190.42 Interdendritic 63.993.7811.32 2.992.408.045.941.13 k'B 0.91 1.14 1.22 1.91 4.03 0.45 0.71 0.37 LMSX-15 k'A 0.91 1.26 1.22 1.91 3.94 0.46 0.72 0.44 Dendritic 57.374.5214.51 5.119.353.554.59 1.63 Interdendritic 61.414.0412.17 3.363.167.534.52 1.38 k'B 0.93 1.12 1.19 1.52 2.96 0.47 1.02 1.18 LMSX-16 k'A 0.92 1.11 1.16 1.78 3.99 0.47 0.74 1.15 Dendritic 55.414.2413.69 5.779.663.524.52 3.59 Interdendritic 61.493.6810.97 3.101.6810.116.34 3.11 k'B 0.90 1.15 1.25 1.86 5.75 0.35 0.71 1.15 LMSX-17 k'A 0.90 1.32 1.24 2.01 6.33 0.38 0.71 1.08 Dendritic 57.234.1313.86 6.0610.123.844.41 0.80 Interdendritic 61.843.7111.22 2.912.238.746.47 2.95 k'B 0.93 1.11 1.24 2.08 4.54 0.44 0.68 0.27 LMSX-18 k'A 0.94 1.03 1.07 1.69 2.63 0.62 0.80 0.33

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38 With kB exhibiting the same trend as kA, the composition effect s and some of the elemental interactions were plotted. When examining the effect of elemental variations, all the compositional effects were compared dire ctly to the baseline alloy LMSX-1. Note that kB is calculated using equation 1-1, however the data used in this calculation was obtained from data collection me thod described in this paper. 4.3.1. Cobalt Partitioning The effects of cobalt variations (LMSX-1, -2 and -3; 12.2 wt% Co, 8.0 wt% Co, and 4.0 wt% Co respectively) on the kB values were all of the elements in the alloy were plotted against increasing Co content. From th is graph (Figure 4-8), it can be seen that increasing Co content decreased the segregation of the elements that partition to the dendrite core. The largest decrease in segr egation occurs with Re followed by W, Co itself, and finally Cr. The effect on Cr is a very small decrease in segregation over the range of 4 wt% to 12.2 wt% Co. Whereas the e ffect of Re decreased markedly as the Co level is increased to the 8 wt% Co, and then remains constant with further increasing Co. It should be noted that the in crease in Co content in these alloys results in a decreased segregation of Co itself, but only slightly. When looking at the elements that segregat e to the interdendritic region (Figure 49), increasing the Co content also decreased the segregation of Al and Ta, but slightly increased the segregation of Ni. The decrease in partitioning for Al with increasing Co content greater than that for Ta, but the Ta fo llows the same trend as Re does in that the degree of segregation is decr eased to the 8 wt% Co point and then becomes essentially constant. As was stated, the segregation of Ni increased with increasing Co, but Ni is the only element that was observed to exhibit increased segregation when increasing Co content.

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39 4.3.2. Chromium Partitioning The alloys with varying chromium conten t were the second group examined. This series of alloys consists of LMSX -5, -1, and -4 (2.1 wt% Cr (3 at%), 4.1 wt% Cr (5 at%), and 6.15 wt% Cr (7 at%) respectively). The e ffects of this addition on the elements in the alloy (Ni, Cr, Co, W, Re, Ta, and Al) was ex amined and characterized. Increasing the Cr concentration increased the segregation of Re, Co, and Cr. The increase in Re segregation, being the most consistent and pr onounced when compared to that of Co and Cr. Co partitioning increased as Cr cont ent was increased, and the Cr partitioning did increase slightly. In the ba seline alloy, LMSX-1, and the hi gh Cr content alloy, LMSX-4, Cr was observed to partition to the dendrite co re. But in the low Cr alloy (LMSX-5), Cr was observed to segregate to th e interdendritic region. W had a different response to this change in concentration; as Cr content increased, the W partitioning decreased. The partitioning coefficient for Co at the 2.1 wt% Cr was the lowest found in this investigation indicating that Co partitioned the least in this alloy. Figure 4-10 shows the effect graphically of increasing Cr con centration on the segregation of elements partitioning to the dendritic region.

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40 k' Comparison for LMSX-10 0.5 1 1.5 2 2.5 3 3.5 NiCrCoWReTaAlk' Technique A Technique B Figure 4-2: k values for LMSX-1 for techniques A (orange ) and B (blue). The green line is at k = 1. k' Comparison for LMSX-130 1 2 3 4 5 6 7 NiCrCoWReTaAlk' Technique A Technique B Figure 4-3: k values for LMSX-13 for t echniques A (orange) and B (blue). The green line is at k = 1

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41 k' Comparison for LMSX-180 1 2 3 4 5 6 7 8 NiCrCoWReTaAlPdk' Technique A Technique B Figure 4-4: k values for LMSX-18 for t echniques A (orange) and B (blue). The green line is at k = 1. k' Comparison for LMSX-80.00 1.00 2.00 3.00 4.00 5.00 6.00 NiCrCoMoWReTaAlk' Technique A Technique B Difference Figure 4-5: k values for LMSX-8 for techniques A (orange ) and B (blue). The green line is at k = 1. The difference is noted by a circle.

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42 Plot of Molybdenum Segregation in LMSX-7 and -8 with Normalized PDAS0.00 0.50 1.00 1.50 2.00 2.50 00.20.40.60.81 Normalized PDASwt% Mo LMSX-7 LMSX-8 Figure 4-6: Mo segregation pl ot for LMSX-7 and -8. White points were used in kB analysis. Second order trendlines are also shown for both alloys. Plot of Aluminum Segregation in LMSX-1 and -18 with Normalized PDAS 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 00.20.40.60.81 Normalized PDASwt% Al LMSX-1 LMSX-18 Figure 4-7: Al segregation plot for LMSX-1 and -18 shown for comparison. White points were used in kB analysis. Second order tre ndlines are also shown for all alloys.

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43 The effect of increasing Cr on elements that partition to the interdendritic region is shown in Figure 4-9. The partitioning behavior of Ni, Al, and Ta due to varying the Cr concentration was not consistent. Ta showed a linear increase in partitioning as the Cr. The partitioning of Ni did not appear to be affected by the change in Co content. The graph in Figure 4-11 shows a decrease in the pa rtitioning coefficient, but the variation are small and may be due to experimental data scatter. The effect of Cr content on the partitioning of Al was still different than that of Ni and Ta. Al partitioning decreased as Cr content increased. 4.3.3. Rhenium Partitioning Alloys LMSX-9, -10, -1 and -11 were used to evaluate the changes in partitioning due to increasing Re content. LMSX-9 is a first generation superalloy with 0 wt% Re, LMSX-10 is a second generation superalloy with 1 at% Re ( 3 wt%), LMSX-1 is the baseline and is a third genera tion superalloy with 2 at% Re ( 6 wt%), and LMSX-11 is a model alloy with 3 at% Re ( 9 wt%) and was added to examine the effect of a large Re additions on alloy stability. Figure 4-12 contains the kB curves for elements segregating to the dendritic region, and Figure 4-13 contains the kB curve for elements that segregate to the interdendritic region. Of the elements segregating to the dendrite cores, Re shows the largest increase in partitioning due to the increase in Re concen tration. The partitioning coefficient for Re in LMSX-11 (8.95 wt% Re) was the largest k va lue observed in this experiment. Cr and Co also exhibit increasing se gregation levels when the Re content was increased up to the 5.95 wt% Re (LMSX-1) concentration. At the highest Re concentration, the Co showed a slightly greater propensity to partition to the dendrite core.

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44 Partitioning Effect with Varying Co0.000 1.000 2.000 3.000 4.000 5.000 6.000 2468101214wt% Cok' Cr Co W Re Figure 4-8: Partitioni ng effects due to increasing Co c oncentration for elements showing a preference to segregate to the dendritic region. Partitioning Effect with Varying Co0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 2468101214wt% Cok' Ni Ta Al Figure 4-9: Partitioni ng effects due to increasing Co c oncentration for elements showing a preference to segregate to the interdendritic region.

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45 Partitioning Effect with Varying Cr0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 1234567wt% Crk' Cr Co W Re Figure 4-10: Partitioning effects due to incr easing Cr concentration for elements showing a preference to segregate to the dendritic region. Partitioning Effect with Varying Cr0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 1234567wt% Crk' Ni Ta Al Figure 4-11: Partitioning effects due to incr easing Cr concentration for elements showing a preference to segregate to the interdendritic region.

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46 The Cr continued to exhibit a limited degree of segregation to the de ndritic core, and the final kB values for Cr and Co for LMSX-11 ( 8.9 wt% Re) were virtually the same. LMSX-11 contained the most se vere segregation and, theref ore the highest partitioning coefficients for Cr, Co, and Re for this investigation. Increased Re contents also resulted in an increasing segregation of Ni, Ta, and Al. Ta showed the greatest degree of segregat ion for these three elements, followed by Al, and then Ni. Ni showed a linear decrease in kB (increasing segregation) as the Re concentration was increased. Ta and Al show ed somewhat parabolic decreasing trends in k as the Re content increased. Unlike in the Re bearing alloys, Ni partitioned to the dendritic region for LMSX-9 (0 wt% Re). LMSX-11 showed the greatest amount of partitioning in Ni, Al, and Ta for this investig ation. In general, the segregation behavior of all of the elements was reduced to its lo west levels in the 0 wt% Re (LMSX-9) alloy, and the highest levels in the 8.9 wt% (LMSX-11) alloy. 4.3.4. Tungsten partitioning The effects of increasing the W concentr ation were also evaluated in this investigation by comparing LMSX-1 (5.85 wt% W) and LMSX-6 (8.9 wt% W). Figures 4-14 and 4-15 show the changes in the partiti oning coefficient for the base elements (Ni, Cr, Co, W, Re, Ta, and Al) as the concentration of W is in creased. W had a variety of effects on the elements that commonly segregat e to the dendritic regi ons (Re, W, Co, and Cr). The first effect noted was that the increas ed concentration of W, also resulted in an increased W partitioning coefficient. This was the only element with kB greater than one (i.e. elements that partitioned to the dendrit e core) that showed an increase in this segregation. Co and Cr were unchanged as the W concentration was increased.

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47 Somewhat unexpectedly, the increase in W content resulted in a decrease in the segregation of Re. Similar to the varied segregation behavior in the dendritic segregating elements, the elements segregated to the interdendritic re gion also showed very different responses. Raising the W levels in the alloy caused Ta a nd Al to segregate to a greater extent, with Ta exhibiting a greater degree of segregation th an Al. In a pattern similar to that shown by Re for this series, the partitioning of Ni decreased (kB approaching one) with increasing W content. 4.3.5. Tungsten Partitioning with an Addition of Molybdenum LMSX-7 and -8 both had a 1 at% Mo additi on to evaluate the effects of Mo on the segregation behavior of the alloys. In addition, the W concentration in LMSX-7 was decreased to 3.1 wt% (1 at%). Re, W, Cr, a nd Co all segregated to the dendrite core regions of the as-cast structure (Figure 416). As the W concentration was decreased from 5.85 wt% to 3.1 wt%, Re showed the larges t decrease in segrega tion of the elements in this alloy. The segregation behavior of W itself was also decrease slightly. The partitioning behavior of Co was unaffected by the decrease in W concentration. The degree of Cr segregation increased as the W concentration decreased. Mo, Ni, and Ta all exhibited a decreased degree of segregation as the W concentration was decreased. The change in W had no obvious effect on the Al segregation behavior. The lowest kB values for W and Re (indicating the least amou nt of segregation) in this investigation were found in LMSX-7. Figure 4-17 clearly illustrates the eff ect of decreasing W concentration the segregation be havior of Ni, Ta, Mo, and Al.

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48 Partitioning Effect with Varying Re0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000 012345678910wt% Rek' Cr Co W Re Figure 4-12: Partitioning effects due to incr easing Re concentration for elements showing a preference to segregate to the dendritic region. Partitioning Effect with Varying Re0.000 0.200 0.400 0.600 0.800 1.000 1.200 012345678910wt% Rek' Ni Ta Al Figure 4-13: Partitioning effects due to incr easing Re concentration for elements showing a preference to segregate to the interdendritic region.

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49 Partitioning Effects with Varying W0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 55.566.577.588.599.5wt% Wk' Cr Co W Re Figure 4-14: Partitioning effects due to increasing W concentration for element segregating to the dendritic region. Partitioning Effects with Varying W0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 55.566.577.588.599.5wt% Wk' Ni Ta Al Figure 4-15: Partitioning effects due to increasing W concentration for element segregating to the in terdendritic region.

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50 Partitioning Effects with Varying W (Mo added)0.00 0.50 1.00 1.50 2.00 2.50 3.00 22.533.544.555.566.57wt% Wk' Cr Co W Re Figure 4-16: Partitioning effects due to decr easing W concentration with the addition of 1 at% Mo for element segrega ting to the dendritic region. Partitioning Effect with Varying W (Mo added)0.00 0.20 0.40 0.60 0.80 1.00 1.20 22.533.544.555.566.57 wt%k' Ni Mo Ta Al Figure 4-17: Partitioning effects due to decr easing W concentration with the addition of 1 at% Mo for element segregating to the interdendritic region.

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51 4.3.6. Molybdenum Partitioning By examining the segregation behavior of the baseline (LMSX-1) and LMSX-8 alloys, the effect of a si ngle addition of Mo could be observed. The elemental segregation behavior of elements that partit ion to the dendritic regions is shown in Figure 4-18 and Figure 4-19 illustrates the segreg ation behavior of elements that partition to the interdendritic region. The addition of 1 at% Mo decreased the overall segregation of nearly every elem ent in the alloy. kRe decreased the most substantially followed by kW, and finally kCo. Cr partitioning was virtually unaff ected by the addition of Mo to this alloy. The elements that exhibited partitioning coefficients (k) less than one, also exhibited a similar segregation behavior w ith the addition of 1 at% (1.6 wt%) Mo. The segregation of Al was observ ed to decrease to the grea test degree followed by Ni and finally Ta. Mo was observed to partition to the interdendritic regions, and partitioned more strongly than Al and less than Ta. 4.3.7. Ruthenium Partitioning Ruthenium has become an alloying addition of great interest and is currently being added to the newer superalloys28,39,, which are called fourth ge neration superalloys. To investigate the effect of R u, two alloys were included in the alloy design matrix (see Table 3-1). The first was LMSX-16, which was the baseline LMSX-1 alloy with an addition of 1 at% Ru (1.6 wt%). The sec ond alloy, LMSX-17, contained 2 at% Ru (3.2 wt%). The addition of 1 at% Ru had no affect on Re segregation. However, when the Ru content was increased to 2 at%, Re begins to partition more dramatically. The remaining elements with kB greater than one (i.e. partition to the dendrite core) al l show essentially linear trends (Figure 4-20) for all three Ru concentrations (LMSX-1 (0 at% Ru), LMSX-

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52 16 (1 at% Ru), and LMSX-17 (2 at% Ru)). Cr segregated to a lesser degree than Re for all of the alloys in this study, and showed a linear increase in segregation as the Ru concentration increased. The kB values for Co and W both increased by a similar amount with the increase in Ru content. With the increase in Ru, Ru itself showed a decrease in its segregat ion behavior. The kB for Co in LMSX-17 was the largest value found for Co in this investiga tion, indicating that Ru strongly influences the segregation behavior of Co. Of the elements segregati ng to the interdendritic re gion in LMSX-1, -16, and -17, Ta showed the greatest degree of segregati on followed by Al and finally Ni (Figure 421). The segregation of Ta does not change until the Ru content was greater than 1.6 wt% (1 at%). When the Ru concentration was increased above 1 at%, Ta began to segregate to the interdendritic region more s ubstantially than at lower Ru concentrations. Al followed a similar pattern to Ta, but not as strongly. It should al so be noted that Al segregation behavior seemed to be reversed in the 1 at% Ru alloy since Al was observed to segregate to the dendritic region in LMSX-16. Ni was the only element that was relatively unaffected by the addition or Ru, and exhibited only a slight trend towards increased segregation with the increasing Ru content. 4.3.8. Palladium Partitioning The effect of Pd, a precious metal group element, was examined using LMSX-18 (1 at% Pd). Of the elements that exhibited tend encies to segregate to the dendrite cores, Re was affected the most by the Pd addition, a nd then followed by W (Figure 4-22). Both Re and W showed increased segregation as Pd was introduced into the alloy. Although Cr and Co partitioning both increased with th e increasing Pd content, it was not to the extent of the increase observed in W and Re.

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53 Partitioning Effect with Varying Mo0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 00.20.40.60.811.21.41.61.8 wt% Mok' Cr Co W Re Figure 4-18: Partitioning effects due to the addition of 1 at% Mo for element segregating to the dendritic region. Partitioning Effects with Varying Mo0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 00.20.40.60.811.21.41.61.8 wt% Mok' Ni Ta Al Mo Figure 4-19: Partitioning effects due to the addition of 1 at% Mo for element segregating to the interdendritic region.

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54 Partitioning Effect with Varying Ru0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 00.511.522.533.5 wt% Ruk' Ni Ta Al Figure 4-20: Partitioning effects due to Ru addition for element segregating to the dendritic region. Partitioning Effect with Varying Ru0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000 00.511.522.533.5 wt% Ruk' Cr Co W Re Ru Figure 4-21: Partitioning effects due to Ru addition for element segregating to the interdendritic region.

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55 The presence of Pd in the alloy (LMSX-18) caused a decrease in segregation of Ni to the interdendritic regions (Figure 4-23). Segregation for Al and Ta both increased due to the addition of 1.7 wt% (1 at%) Pd, and th eir increases were similar in magnitude. From the kB values calculated, Pd itself segregated heavily to the interdendritic region. 4.3.9. Tungsten and Molybdenum Partitioning Interactions Although the segregation beha viors of alloys with an increasing W content (LMSX-1 and -6), with an addition of Mo (LMSX-1 and -8), and with decreasing W content with an addition of Mo (LMSX-7 and -8) were discussed, the segregation behavior due to substituting Mo for W was evaluated (LMSX-1 and -7, and LMSX-6 and -8) for interactions and consistency. These gr aphs from this evaluation are presented in See Figure 4-24. The first alloys compared were betw een LMSX-1 (5.85 wt% W, 0 Wt% Mo) and LMSX-7 (3.1 wt% W, 1.6 wt% Mo). The segr egation behavior for those elements whose partitioning coefficient, kB, value is greater than one are Re, W, Cr, and Co. The substitution of 1 at% Mo for 1 at% W caused a decrease in the segregations of Re, W, and Co. The decrease in segregation for Re was the most significant followed by W and finally Co, which showed only a slight decreas e in segregation. Cr segregation increased slightly due to this alloy m odification. All of the elemen ts that segregated to the interdendritic region exhibited a decrease in pa rtitioning due to the decrease in W content and the Mo addition. The partitioning of Al was reduced to the grea test degree, followed by Ni. The degree of segregation observed fo r Mo was intermediate to Al and Ni, but since it is only one point no further observati on can be made. The segregation of Ta was also decreased, but not to the extent of Ni.

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56 Partitioning Effects due to Pd Addition0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 00.20.40.60.811.21.41.61.8 wt% Pdk' Ni Ta Al Pd Figure 4-22: Partitioning effects due to Pd addition for element segregating to the dendritic region. Partitioning Effects due to Pd Addition0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 00.20.40.60.811.21.41.61.8 wt% Pdk' Cr Co W Re Figure 4-23 Partitioning effects due to Pd addition for element segregating to the interdendritic region.

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57 To verify the trends shown in decrea sing W content with an addition of Mo, LMSX-6 (8.6 wt% W, 0 wt% Mo) and -8 (5.85 wt% W, 1.6 wt% Mo) were compared. All of the trends noted in the LMSX-1 and -7 comparison were present in the evaluation of LMSX-6 and -8 (Figure 4-25), but the magnitudes had changed. The segregation behavior of Re was still obser ved to decrease with decreasi ng W content, but at a lower rate than the alloys with a lower concen tration of W. W exhibited more initial segregation due to the increased W content of LMSX-6, but d ecreased to nearly the same kB values for both LMSX-7 and -8 indica ting an increased segregation at high W concentrations. Ta and Ni both exhibited great er decreases in segreg ation behavior when the W content was reduced from 8.6 to 5.85 wt% and 1.6 wt% Mo was added. However, Ta and Ni were both initially more segr egated in LMSX-6 than LMSX-1. The segregation behavior of Co was observed to decrease more, but like Ni and Ta, was to a greater extent segregated in LMSX-6 than LMSX-1. Cr and Al segregation did not indicate any change due to d ecreasing W from a high content to an intermediate content combined with adding Mo. When comparing the degree of segregation in these four alloys (LMSX-1, -6, -7 and -8), LMSX-8 e xhibited the least amount of segregation. 4.3.10. Tantalum and Aluminum Pa rtitioning Interactions The next group of interactions observed co me from those alloys that had varying amounts of both Ta and Al (LMSX-12 and -13). LMSX-12 is a modified baseline alloy with 4 at% Ta (11.2 wt%, termed high Ta) a nd 12 at% Al (5 wt%, termed low Al). LMSX-13 contained a reduced Ta content (2 at%, 6 wt% termed low Ta) and an increased Al concentration (14 at%, 6.15 wt% termed high Al). Comparing the elements of these alloys to one another as well as the baseline (LMS X-1) was done to characterize

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58 Partitioning Interactions due to Decreasing W and a Mo Addition0.000 0.500 1.000 1.500 2.000 2.500 3.000 68 Alloy (LMSX-X)k' Cr Co W Re Ni Ta Al Mo Figure 4-24: Partitioning trends for elemen ts in LMSX-1 and-7. Difference in the two alloys is that LMSX-7 contains 3.1 wt% W and an addition of 1.6 wt% Mo. Partitioning Interactions Due to Decreased W and a Mo Addition0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 17 Alloy (LMSX-X)k' Cr Co W Re Ni Ta Al Mo Figure 4-25: Partitioning trends for elements in LMSX-6 and -8. Difference in the alloys is that LMSX-6 contains 8.6 wt% W, 0 wt% Mo, and LMSX-8 contains 5.85 wt% W, 1.6 wt% Mo.

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59 the interactions. Recall that all of these alloys have similar volume fractions of , so the alloy modifications are only intended to alter the composition of the phases. The increase in Ta to 11.2 wt% coupled with a decrease in Al to 5 wt% (LMSX-1 to LMSX-12) resulted in a variet y of effects on the elements in the alloys (Figure 4-26). Increased Ta and decreased Al contents cause d a decrease in the se gregation of Re, but Re remained the most segregated element present in this alloy. Ta showed the second greatest decrease in segregation which is surp rising since the amount of Ta was increased by 1 at% ( 3 wt%). The only other el ement that showed some effect due to this change was Cr, whose partitioning increased. The ot her elements in the system, W, Co, Ni, and Al did not show any significant change in se gregation due to the modification in alloy chemistry. To continue to evaluate the role of the formers, another combination of alloys was used to begin to examine partitioning interactions (LMSX-1 and -13). The difference in chemistry for these two lies in LMSX-13 which contains a reduced quantity of Ta (from 8.9 wt% down to 6 wt%) and an increase in Al (f rom 5.55 wt% up to 6.15 wt%). The overall trend for this alloy modifi cation was an increase in segregation for all elements except for Cr which began to segregat e to the interdendritic region. The largest increase in segregation of the elements that exhibited dendritic se gregation, was in the segregation for Re, which nearly doubled. Th e next greatest increase in segregation was observed in W. Co was the only element that did not appear to be affected by the change in alloy chemistry (Figure 4-28). Ta also exhi bited a significant increase in segregation of those elements that had a kB less than one. However, the segregation of Ta was significantly lower in magnitude in comparison to Re. Al segregation also increased to a

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60 lesser extent than Ta. Ni exhi bited a slight increase in part itioning due to this change in chemistry (Figure 4-29). LMSX-12 was also compared directly to LMSX-13 to further characterize these alloy modification effects (Fi gures 4-30 and 4-31). Not su rprisingly, the trends reported for the LMSX-1 to LMSX-13 interactions we re to be observed when examining LMSX12 and LMSX-13. Re segregation increased ag ain, and by a factor of more than two. W segregation also increased, but not to the degree of Re. Ag ain, Co partitioning appeared unaffected by these alloy modifications. The segregation to the in terdendritic region increased to the largest degree for Ta. Al se gregation did increase, but not to the extent of Ta, and the degree of Ni increased the least. 4.3.11. Tantalum and Aluminum Partitioning Interactions with an Addition of Titanium Ta and Al are not the only formers in Ni-base superalloys. Ti is also considered to be a former. The baseline alloy, LMSX -1, was modified again with Ti additions for either Ta or Al, to c ontinue to look at the effects of the formers. LMSX-14 is LMSX-1 with an addition of 0.80 wt% (1 at%) Ti and a decrease in Ta from 8.9 wt% (3 at%) down to 6.0 wt% (2 at%) This change in alloy chemistry changed the segregation of W a nd Cr causing them both to segregate more to the dendrite core, with W segregating more strongly than Cr. Re and Co segregation patterns had no observable change in this comparison (Figur e 31). Ta and Al both showed about the same increase in partitioning to the interdendritic region from the baseline to this modified chemistry. Ti itself exhibited the strongest segregation to the interdendritic region. The partitioning behavior of Ni decreased slightly due to these alloy modifications (Figure 32).

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61 Partitioning Interactions Due to Increasing Ta and Decreasing Al0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 112 Alloy (LMSX-X)k' Cr Co W Re Ni Ta Al Figure 4-26: Partitioning trends for elemen ts between in LMSX-1 and-12. Difference in the two alloys is that LMSX-12 contains 11.2 wt% Ta and 5.0 wt% Al. Partitioning Interactions Due to Decreasing Ta and Increasing Al0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 113 Alloy (LMSX-X)k' Cr Co W Re Figure 4-27: Partitioning trends for elem ents between in LMSX-1 and-13. Elements segregating to the dendritic region shown. Difference in the two alloys is that LMSX-13 contains 6.00 wt% Ta and 6.15 wt% Al.

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62 Partitioning Interactions due to Decreasing Ta and Increasing Al0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 113 Alloy (LMSX-X)k' Ni Ta Al Figure 4-28: Partitioning trends for elem ents between in LMSX-1 and-13. Elements segregating to the interde ndritic region shown. Difference in the two alloys is that LMSX-13 contains 6.00 wt% Ta and 6.15 wt% Al. Partitioning Interactions due to Variations in Ta and Al0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 1213 Alloy (LMSX-X)k' Cr Co W Re Figure 4-29: Partitioning trends for elem ents between in LMSX-12 and-13. Elements segregating to the dend ritic region shown.

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63 Partitioning Interactions due to Varying Ta and Al0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1213 Alloy (LMSX-X)k' Ni Ta Al Figure 4-30: Partitioning trends for elem ents between in LMSX-12 and-13. Elements segregating to the inte rdendritic region shown. The effect of substituting Ti for Al was evaluated with LMSX-1 and -15, in which the formers were again modified (Figure 33 and 34). LMSX-15 is a variant of LMSX14 in that it contains the same addition of 1 at% (0.80 wt%) Ti, but LMSX-15 also had a reduction in Al from 5.10 wt % (13 at%) Al down to 5.0 wt% (12 at%). Of elements segregating to the dendrite, Re again showed the largest increase in segregation due to the alloy modification, followed by W. Cr segregation also incr eased, but only slightly, and Co showed even less of a change than Cr due to this alloy modification. Ta and Al both showed the same degree of increase in segrega tion with the substituti on of Ti for Al. Ni appeared to be unaffected by this modificat ion in alloy chemistry. Ti itself again segregated to the interdendritic regio n, more strongly than any other element. Using the combination of LMSX-14 and LMSX-15, it is now possible to observe the interactions between Ta and Al with the Ti add ition being constant. When

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64 comparing, LMSX-14 and -15, Re showed a la rge increase in segregation due to the increased Al content, decreased Ta content, and the Ti addition. W and Co exhibited an increase in kB of similar magnitude due to the change in Ta and Al concentrations with Ti in the matrix. The segregation of Cr ha d no appreciable change with the modification in alloy chemistry. Ti showed a greater degree of segregation than any other addition that partitioned to the interdendritic region. The kB for Ti in LMSX-15 was slightly lower than that of LMSX-14 indicating an increa se in partitioning with increasing Ta and decreasing Al contents. Ni a nd Al both exhibited similar in creases in segregation with alloy modifications. Ta showed no change in segregation due to these changes in base alloy chemistry. 4.4. Segregation Behavior The use of partitioning coefficients to describe the segregation of elements in an ascast alloy is useful to un derstand castability, defect fo rmation, and heat treatment requirements. However, the magnitude of se gregation obtained from the calculation of the partitioning coefficient may not be indica tive of the degree of segregation that is occurring. Also, in an element that show s a relatively wide scatter and no visible partitioning preference, (i.e. Cr in this expe riment) the actual partitioning, dendritic or interdendritic, that is occurring may not be accurate in all cases. The line scans used in this study, deve lop a graphical representation of the compositional variations that occur, due to segregation after so lidification and some degree of back diffusion have occurred. Fi gure 4-37 depicts this segregation between dendrites as a surface that has a varying composition depending on the distance from the dendrite itself. The curved lines between the dendrite cores is an id ealized representation

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65 Partitioning Interaction due to D ecreasing Ta with a Ti Addition0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 114 Alloy (LMSX-X)k' Cr Co W Re Figure 4-31: Partitioning trends for elem ents between in LMSX-1 and-14. Elements segregating to the dendritic region shown. Difference in the two alloys is that LMSX-14 contains 6.00 wt% Ta and an addition of 0.80 wt% Ti. Partitioning Interaction due to D ecreasing Ta with a Ti Addition0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 114 Alloy (LMSX-X)k' Ni Ta Al Ti Figure 4-32: Partitioning trends for elem ents between in LMSX-1 and-14. Elements segregating to the interde ndritic region shown. Difference in the two alloys is that LMSX-14 contains 6.00 wt% Ta and an addition of 0.80 wt% Ti.

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66 Partitioning Interaction Due to Decreasing Al and a Ti Addition0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 115 Alloy (LMSX-X)k' Cr Co W Re Figure 4-33: Partitioning trends for elem ents between in LMSX-1 and-15. Elements segregating to the dendritic region shown. Difference in the two alloys is that LMSX-15 contains 5.10 wt% Al and an addition of 0.80 wt% Ti. Partitioning Interaction Due to Decreasing Al and a Ti Addition0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 115 Alloy (LMSX-X)k' Ni Ta Al Ti Figure 4-34: Partitioning trends for elemen ts between in LMSX-1 and-15. Elements segregating to the interde ndritic region shown. Difference in the two alloys is that LMSX-15 contains 5.10 wt% Al and an addition of 0.80 wt% Ti.

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67 Partitioning Interactions Due to Varying Ta and Al with an Addition of Ti0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 1415 Alloy (LMSX-X)k' Cr Co W Re Figure 4-35: Partitioning trends for elem ents between in LMSX-14 and-15. Elements segregating to the de ndritic region shown. Partitioning Interactions Due to Varying Ta and Al with an Addition of Ti0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1415 Alloy (LMSX-X)k' Ni Ta Al Ti Figure 4-36: Partitioning trends for elem ents between in LMSX-14 and-15. Elements segregating to the inte rdendritic region shown.

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68 of solidification, back diffusion, and segrega tion of an element that segregates to the dendrite core. Note that the composition of th e interdendritic region is depleted in the element while the core is enriched. Also it should be noted that the solidification/segregation lines are represented by curves. The use of curves was based on the observation of the general trends of the data points determined by EMPA. For each set of EMPA data points, a s econd order trendline was determined and then the equation that descri bes the trendline was determined. This was done for a normalized primary dendrite arm spacing (PDAS). Using this second order equation, the curvature for the trendline was determined. Curvature is defined as the amount by whic h a curve, surface, or other manifold deviates from a straight line.42 Mathematically, curvature, or comes from the second derivative of an equation, or more explicitly, 42 2 / 3 2 2 21 x y x y. equation (4-1) But this can be simplified to just the second derivative as previously mentioned due to the desire to determine the maximum value for the given equation. Thus, putting this in terms of the trendline equations, it is simply 2 a (where a is from a x2 + b x + c from the trendline equation) because th e only point of concern is at the apex which can be considered x = 0. It should be noted that care should be taken with the calculation of the curvature, The sign of is determine by the line scan it self. Since the line scans in this experiment were done from dendrite core to dendrite core thr ough the interdendritic region, one combination of positive and negative curvature values is achieved. If the

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69 scan were done from the interdendritic re gion, through the dendrite core, and back into the interdendritic region, another combination of positive and negative s are returned which are the opposite sign of th e first example. By doing the scans dendrite core to dendrite core, the resultant signs reflect those do ne by the previous k analysis in this and other studies. Figure 4-37: Red lines indicated solidificat ion/segregation gradie nts between dendrite cores within the interdendritic region for an element that segregates to the dendrite cores. The dendrites are represented in yellow. With the trendline equations determined, the could be calculated. was used to explain the segregation behavior in the various alloys. The curvature, values were calculated and then plotte d against the following: Cobalt. By comparing LMSX-1, -2, and -3. Chromium. By comparing LMSX-1, -5, and -5. Rhenium. By comparing LMSX-1, -9, -10, and -11. Ruthenium. By comparing LMSX-1, -16, and -17. Tungsten. By comparing LMSX-1 and 6. Molybdenum. By comparing LMSX-1 and -8

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70 Palladium. By comparing LMSX-1 and -18. Tungsten with a Molybdenum addition. By comparing LMSX-7 and -8. Variation of Tantalum and Aluminum from the baseline. LMSX-1, -12, and LMSX-1, -13. Variation between Tantalum and Aluminum. LMSX-12 and -13. Variation of Tantalum and Aluminum fr om the baseline with an addition of Titanium. LMSX-1, -14, and LMSX-1, -15. Variation between Tantalum and Aluminum with an addition of Titanium. LMSX14 and -15. V Variation between decreasing Tungsten and increasing Mo lybdenum. LMSX-1, -7 and -6, -8 Table 4-3 contains the values and the kB values for comparison purposes. Similar to previous results, the trend of k gr eater than unity indicated segregation to the dendrite core, along with greater than zero was consis tent for partitioning to the dendritic regions for the eighteen model alloys.11,35 Similarly, the trend of k less than unity and less than zero was also consistent with previous results for the eighteen model alloys, indicating consistency in dete rmining overall segregation path to the interdendritic regions. Although most results for these comparisons were similar, there was some disagreement in the elements that showed only a weak segregation preference between the dendritic and interdendritic region. 4.4.1. Cobalt Segregation Behavior The value was calculated for each element in each of LMSX-1, -2, and -3 and then plotted against increasing Co concentration. Figure 4-38 shows the extent of change of resulting from this compositional variation. Cr, Ni, W, and Re all partitioned to the dendritic region, and Al, Ni, a nd Ta all segregated to the interdendritic region. The

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71 elements W, Re, Ta, and Al all show a decrea se in their segregation as the Co content was increased. Co and Ni segregated slight ly more. Cr segregation did not change significantly. Re segregates more than a ny of the elements in these alloys over all concentrations of Co, and exhibited a maximum in segr egation at 4 wt% Co. Re segregation decreased slightly wi th the addition of 4 wt% Co to the alloy (for a total of 8 wt% Co). With 12.2 wt% Co present in the alloy, the Re dropped to the lowest level in this study. Ta showed the next greatest effect due to increasi ng Co content. The increase in Co from 4 wt% to 8 wt% showed little effect on Ta, but the segregation began to decrease (become less negative) when the Co concentration was in creased to 12.2 wt%. Ni showed the third greatest segregation be havior in this seri es of alloys. The increase in Co concentration caused an initia l increase in partitioni ng of Ni when Co was increased from 4 wt% to 8 wt%. The remaini ng increase in Co had no further effect on the segregation of Ni. W showed a linear de crease in segregation as the Co content was increased from 4 wt% to 12.2 wt%. The segr egation of Co followed a more expected trend of increasing as the concentration of it increased in the system from 4 wt% to 8 wt% Co, but did not change beyond the 8wt% Co concentration. Co in LMSX-3 was the lowest value for Co found in this part of this investigation. The partitioning of Al was the opposite of the trend observed by Co. There was no change in Al segregation from 4 wt% Co to 8 wt% Co, and then the partitioning decreased with further additions of Co. 4.4.2. Chromium Segregation Behavior LMSX-4, -1, and -5 were used to evaluate the segregation behavior of the elements in the alloys with varying Cr contents. LMSX-5 contained 2.1 wt% Cr and LMSX-4 contained 6.15 wt% Cr. This analysis is pres ented from the low Cr content alloy to the

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72 high content alloy (Figure 4-39). When the analysis was preformed, Re was observed to exhibit the greatest degree of segregation and it partitioned to the dendritic region. The low and baseline levels of Cr had little e ffect on the segregation behavior, but the addition of 4.15 wt% Cr to the high Cr (L MSX-4, 6.15 wt% Cr) brought about a decrease in Re segregation. Ta segregated to the interdendritic region and was the second most strongly segregated element. As Cr was adde d, the partitioning of Ta increased and then remained relatively constant. The addition of Cr brought about a decrease in the third most heavily partitioned element, Ni, which se gregated to the interdendritic region. As the Cr content was increased, the partitioning of Ni decreased in a linear manner. W partitioned to the dendritic region and its segregation decreased linearly as the Cr content increased. Co and Cr both segregated to th e dendrite cores, and bot h showed only slight increases in segregation due to increasing Cr content. However, Co did segregate more strongly than Cr over the entire range of compositions evaluated. Cr exhibited a complete change in segregation. In high Cr alloy (LMSX-4, 6.15 wt% Cr) and the baseline, Cr was observed to segregate to th e dendritic regions. Whereas in low Cr content alloys (LMSX-5, 2.1 wt% Cr) was obser ved to segregate to the interdendritic region. The increasing the Cr content caused Al to segregate to a slightly less, and Al segregated to the interdendritic region. Cr in LMSX-5 was almost zero indicating no preference in segregation.

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73Table 4-3: Comparison of values calculated by kB and Alloy Method Ni Cr Co Mo W Re Ta Al Ti Ru Pd -32.910.7510.02 16.5547.80 -44.98-9.12 1 k'B 0.91 1.04 1.14 1.58 3.10 0.48 0.75 -31.312.3911.60 19.5855.81 -44.98-12.59 2 k'B 0.94 1.20 1.18 1.57 3.04 0.48 0.73 -27.810.885.29 22.3657.96 -45.69-13.01 3 k'B 0.94 1.07 1.23 1.87 4.86 0.44 0.70 -21.361.829.59 13.9040.77 -35.69-8.98 4 k'B 0.93 1.05 1.19 1.52 3.08 0.46 0.81 -35.63-0.209.59 17.6447.36 -27.00-9.12 5 k'B 0.94 0.98 1.04 1.64 2.59 0.54 0.78 -41.481.7114.39 29.2049.66 -38.49-14.91 6 k'B 0.93 1.03 1.16 1.89 2.69 0.41 0.69 -15.250.189.31-2.635.2939.58 -28.92-7.55 7 k'B 0.97 1.10 1.06 0.88 1.41 2.35 0.54 0.84 -25.391.0610.64-1.3912.7539.99 -28.65-9.11 8 k'B 0.94 1.03 1.06 0.82 1.46 2.48 0.50 0.85 1.26-2.275.49 17.990.00 -25.92-4.15 9 k'B 1.01 1.00 1.11 1.62 0.00 0.61 0.86 -16.922.3514.02 22.2331.82 -45.59-7.82 10 k'B 0.96 1.07 1.19 1.60 3.41 0.50 0.83 -65.365.7116.86 15.5186.65 -42.52-16.80 11 k'B 0.87 1.28 1.25 1.73 6.70 0.34 0.65 -28.802.8113.11 16.9147.08 -40.80-10.27 12 k'B 0.94 1.13 1.15 1.57 2.67 0.54 0.77

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74Table 4-3 (cont.): Comparison of values calculated by kB and Alloy Method Ni Cr Co Mo W Re Ta Al Ti Ru Pd -50.02 -1.8911.24 22.5459.26 -25.75-15.32 13 k'B 0.89 0.89 1.20 2.07 5.86 0.34 0.69 -41.27 0.6410.70 22.4143.09 -18.99-11.04-5.59 14 k'B 0.93 1.19 1.10 1.83 3.12 0.44 0.72 0.42 -30.16 2.0713.03 19.6346.81 -30.01-9.43-7.14 15 k'B 0.91 1.14 1.22 1.91 4.03 0.45 0.71 0.37 -33.63 1.6211.37 16.0146.51 -31.27-11.31 0.84 16 k'B 0.93 1.12 1.19 1.52 2.96 0.47 1.02 1.18 -49.64 5.4517.68 20.6264.85 -46.59-15.08 2.75 17 k'B 0.90 1.15 1.25 1.86 5.75 0.35 0.71 1.15 -30.19 3.2818.05 22.0457.72 -36.08-15.76 -19.12 18 k'B 0.93 1.11 1.24 2.08 4.54 0.44 0.68 0.27

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75 4.4.3. Rhenium Segregation Behavior Re is the element that defines the different generations of superalloys and this part of the investigation deals with the effects of segregation due to increasing Re content from 0 wt% Re (LMSX-9, a first generation model superalloy), to 3 wt% Re (LMSXS10, a second generation model superalloy), a nd finally reaching 6 wt% Re (LMSX-1), a third generation model superalloy. To begin to understand the effect of larger quantities or Re on an alloy, an additional 3 wt% Re was added in LMSX-11. This discussion will be related in terms of increas ing Re content from 0 wt% to 8.9 wt%. See Figure 4-40 for graphical representation of the presented information. Normalized Partitioning due to Co-60.00 -40.00 -20.00 0.00 20.00 40.00 60.00 80.002468101214w/o Co Ni Cr Co W Re Ta Al Figure 4-38: Elemental se gregation plots based on due to increasing Co content from 4 wt% to 12.2 wt%.

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76 Normalized Partitioning due to Cr-50.00 -40.00 -30.00 -20.00 -10.00 0.00 10.00 20.00 30.00 40.00 50.00 60.001234567w/o Cr Ni Cr Co W Re Ta Al Figure 4-39: Elemental se gregation plots based on due to increasing Cr content from 2.1 wt% to 6.15 wt%. Re was the most segregated element in the alloys examined in this series, and the degree of segregation increased as more Re wa s added to the system. Re segregated to the dendritic region, and the for Re in LMSX-11 was the larg est observed in this study. Ta, which partitioned to the interdendritic region exhibited an initial increase in segregation when 1 at% Re was added to the system. Af ter this point, the se gregation varied, but remained relatively constant and did not incr ease further. Ni was found to segregate to the dendrite core in LMSX-9 (0 wt% Re), and then began to partition to the interdendritic region, with increasing Re content. The fina l addition of Re (to 8.9 wt%) caused a large increase in the segregat ion behavior of Ni, and Ni became more negative than that of Ta indicating even more Ni segregation was occu rring than Ta. W showed less segregation than Ni, and it segregated to the dendritic re gion. The increase in Re did not affect the segregation behavior of W signi ficantly. The overall behavior of W was nearly constant,

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77 although a slight decrease in segregation was obs erved. Co initially showed very little segregation in LMSX-9, but the addition of 1 at% Re increased its partitioning to the dendritic core. Further additi ons of Re brought about a slight increase in segregation in Co. Al segregated to the interdendritic re gion, and the segregation behavior for Al did not change from the 0, 1, and 2 at% Re concen trations. The addition of the final 1 at% Re caused the segregation to increase slight ly. Cr was observed to segregate to the interdendritic region in LMSX9, but after Re was added, it began to segregate to the dendritic region. As the Re content was in creased, a slow, linear increase in the segregation of Cr was observed. LMSX-11 contained four of the strongest segregating elements in this entire investigation. Ni and Al were the most heav ily segregated to the interdendritic region, and Re were the most heavily segregated to the dendritic core followed by either W and Co, both of which were observed to have th e same degree of segregation. However, minimums in the segregation behavior of se veral elements were observed in the low Re alloys. Al was the lowest in LMSX-9, and Re was at its lowest in LMSX-10.

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78 Normalized Partitioning due to Re-80 -60 -40 -20 0 20 40 60 80 100012345678910w/o Re Ni Cr Co W Re Ta Al Figure 4-40: Elemental se gregation plots based on due to increasing Re content from 0 wt% to 8.9 wt%. 4.4.4. Tungsten Segregation Behavior W was studied at two levels: the baselin e LMSX-1 (5.85 wt% W) and an increased level of W in LMSX-6 (8.6 wt% W). The fi rst observation was th at by increasing the W concentration, all of the elements in the alloys (Ni, Cr, Co, W, Re, Ta, and Al) segregated more strongly (Figure 4-41). Re, W, Co, and Cr all segregated to the dendrite core. The degree of segregation was also in this order with Re being the most heavily partitioned, and Cr being the least partitioned. Ta, Ni, a nd Al all partitioned to the interdendritic region. At the low W level (5.85 wt%), Ta se gregated the most strongly, followed by Ni and then Al. When segregation was examined at the high W level (8.6 wt%), Ni and Ta switched making Ni the most heavily partitioned element segregating to the interdendritic region. In LMSX-6, W was found to segregate more strongly than in any other alloy in this study.

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79 Normalized Partitioning varying W-60.00 -40.00 -20.00 0.00 20.00 40.00 60.0055.566.577.588.599.5w/o W Ni Cr Co W Re Ta Al Figure 4-41: Elemental se gregation plots based on due to increasing W content from 5.85 wt% to 8.6 wt%. 4.4.5. Tungsten Segregation Behavior wi th an Addition of Molybdenum With the addition of 1 at% Mo, LMSX-7 and -8 could be compared to examine the effects of partitioning with a variation in W. The difference in these to alloys is the reduced W content of LMSX-7 to 3.1 wt% from 5.85 wt%. Increasing the W content had little eff ect on the two most heavily segregated elements (Figure 4-42). Re, the most heavily segregated of all, remained segregated to the dendrite core regions. Ta, the second most heavily segregated element, still segregated to the interdendritic region. Ni was still segregating to the interdendritic regions and partitioned more strongly as W was added. The increase in Ni with increasing W was the largest observed in this set of alloys. Initially, Co partitioned more than W itself to the dendritic region. Bu t after increasing th e W concentration, W segregated more strongly than Co. Al segreg ated to the interdendr itic region. As the W

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80 content was increased, Al began to partition to a slightly greater degree, but not to the extent of the other elements with the excep tion of Re and Ta. Cr showed only a small increase in its behavior of partitioning to the dendritic region, as W was added. Mo, which partitioned to the interdendritic regi on, exhibited less segregation as more W was added to the system. The lowest degree of W segregation, W, in this study was observed in LMSX-7. 4.4.6. Molybdenum Segregation Behavior Using the baseline LMSX-1 (0 wt% Mo) and comparing it to LMSX-8 (1.6 wt% Mo), the segregation behavior of Mo coul d be ascertained. Of the elements that segregated to the dendrite core region, Re se gregated the most, followed by W, then Co, and finally Cr (Figure 4-43). The elements th at segregated to the interdendritic region were Ta, Ni, Al, and Mo (in order from greates t degree of segregation to least). Re was the most heavily segregated, and Ta was the second most segregated. The addition of Mo caused both Re and Ta to segregate less, and by about the same amount. This change in chemistry also led to a decrease in the segreg ation Ni and to a lesser degree, W. Al and Cr had no observable change in segregation be havior due to the a ddition of 1 at% Mo. The segregation of Co increased slig htly with the addition of Mo. 4.4.7. Ruthenium Segregation Behavior LMSX-16 and -17 both contained an addi tion of 1 and 2 (1.6 and 3.2) at% (wt%) Ru respectively. Analyses were done on the EM PA data to determine the effect of an addition of Ru on the partitioning of all elemen ts contained in these alloys, and compared The elements that segregated to the dendritic region (in order of gr eatest to least) were Re, W, Co, Cr, and Ru (Figure 4-44). All th e other elements (Ni, Ta, and Al) partitioned to the interdendritic region. The initial addition of 1 at % Ru only showed an effect on the

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81 segregation behaviors of Ni, Ta, and Al. The addition of 1 at% Ru caused Ni to segregate more, and the Ta to segregate less, making Ni the most severely segregated element that partitioned to the interdendritic region. Al segregated only slight more than it had prior to the addition of 1 at% Ru. The addition of a second 1 at% Ru (for a total of 3.2 wt%) ca used a significant increase in the segregation be havior of Re. Ni and Ta also exhibited an increased partitioning behavior. The segregation beha viors of Ni and Ta changed by about the same amount. Although W did segregate more th an Co at both the 1 and 2 at% Ru levels, against the baseline alloy LMSX-1 (0 at%, 0 wt% Ru). the segregation of Co increased more than that of W with the Ru addi tions. The 3.2 wt% Ru caused a continued segregation of Al to the interdendri tic region at the about same rate. Cr also increased at the 3.2 wt% Ru concentration from its leve l at the 1.6 wt% Ru. Ru itself began to partition more as its concentration was in creased, but it showed the least amount of segregation of all the elements contained in the alloy. Ta was observed to exhibit a maximum degree of segregation in LMSX-17.

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82 Normalized Partitioning due to W with Mo Addition-40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.022.533.544.555.566.5wt% W Ni Cr Co W Re Ta Al Mo Figure 4-42: Elemental se gregation plots based on due to increasing W content from 3.1 wt% to 5.85 wt% with an addition of 1.6 wt% Mo to the alloys. Normalized Partitioning due to Mo-50.00 -40.00 -30.00 -20.00 -10.00 0.00 10.00 20.00 30.00 40.00 50.00 60.0000.20.40.60.811.21.41.61.8w/o Mo Ni Cr Co W Re Ta Al Mo Figure 4-43: Element segregation plots based on due to increasing Mo content from 0 wt% to 1.6 wt%.

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83 4.4.8. Palladium Segregation Behavior LMSX-18 was a model alloy with an additional 1 at% (1.7 wt%) Pd. When compared to LMSX-1, the segregation effect s due to this addition may be examined (Figure 4-45). Re, W, Co, and Cr all segregated to the dendrit ic region (and in that order from the most strongly segregated to the leas t), and Ta, Ni, Pd, and finally Al segregated to the interdendritic region (aga in in the order of the highest to lowest partitioning). Re showed the largest increase in segregati on behavior due the addition of Pd. The segregation behavior of Al al so increased with the Pd addi tion. W and Co segregated more strongly with the addition of Pd and the segregation of both elements increased by about the same amount with the Pd addition. Cr increased very slight ly over the range of the addition. The addition of Pd had no affect on the segregation behavior of Ta and Ni. Pd itself was observed to segregate to the interden dritic region to a sli ghtly greater degree than Al. Of all the values of Co observed in these alloys, the maximum value of segregation was observed in LMSX-18. 4.4.9. Tungsten and Molybdenum Segre gation Behavior Interactions The segregation behavior of a decrease in W content and a Mo addition can be examined to develop a qualitative understand ing of elemental interactions that exist between Mo and W. The combinations of LMSX-1, -7 and LMSX-6, -8 were examined to determine the presence of elemental inte ractions and verify th e consistency between these two studies. LMSX-1 and -7 were the first two alloys compared to analyze the effects of a decrease in W (5.85 wt% in LMSX-1 and 3.1 wt% in LMSX-7) and an addition of 1.6 wt% Mo in LMSX-7. When the W conten t was decreased, and as Mo was added, the

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84 Normalized Ru Partitioning-60.0 -40.0 -20.0 0.0 20.0 40.0 60.0 80.000.511.522.533.5w/o Ru Ni Cr Co W Re Ta Al Ru Figure 4-44: Element segregation plots based on due to increasing Ru content from 0 wt% to 3.2 wt%. Normalized Partitioning due to Pd-60.0 -40.0 -20.0 0.0 20.0 40.0 60.0 80.000.20.40.60.811.21.41.61.8w/o Pd Ni Cr Co W Re Ta Al Pd Figure 4-45: Elemental se gregation plots based on due to increasing Pd content from 0 wt% to 1.7 wt%.

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85 segregation behavior of all th e elements (Ni, Cr, Co, W, Re, Ta, and Al) all decreased (Figure 4-46). Re was the most heavily segregated of the elements that partitioned to the dendritic region. The substitution of Mo for W resulted in a decrease in the segregation behavior of Re. This change in alloy chemistry also caused a decrease in the segregation behavior of W. In the baseline alloy (LMS X-1), W segregated more strongly than Co, but when Mo was substituted for W, W segreg ated less than Co, and both segregated to the dendrite core region. Cr decrease very slightly due to the decrease in W and addition of Mo. All of the elements that partitioned to th e interdendritic region segregated less strongly in LMSX-7 than in LMSX-1. Ta wa s the most strongly segregated element that went into the interdendritic region, followed by Ni, and th en by Al. The degree of segregation of Ni decreased more than any other element, when Mo was substituted for W. Al exhibited the smallest decrease in the degree of segregati on with a decreased W content and a Mo addition. LMSX-6 (8.6 wt% W, 0 wt% Mo) and -8 (5.85 wt% W, 1.6 wt% Mo) were compared to verify the trends with Mo subs tituted for W (Figure 447). The segregation behavior of all the elements (Ni, Cr, Co, W, Re, Ta, and Al) all continued to show a decreased segregation due to the substitution of Mo for W. Ni was observed to be more strongly segregated of the elements that segr egated to the interdendritic region, followed by Ta, without the Mo addition (LMSX-6), but when Mo was substituted for W, the degree of segregation for Ni decreased. Ta was then slightly more segregated than Ni in LMSX-8. However, Ta was observed to be mo re strongly segregated in LMSX-8 than in LMSX-6.

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86 Normalized Partitioning Effects due to a Decrease in Tungsten and an Addition of Molybdenum-50.0 -40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 60.017Alloy Ni Cr Co W Re Ta Al Mo Figure 4-46: Elemental se gregation plots based on due to decreasing W to 3.1 wt% and adding 1.6 wt % Mo. Normalized Partitioning Effects due to Decrease in W and an Addition of Molybdenum-60.00 -40.00 -20.00 0.00 20.00 40.00 60.00 68 Alloy (LMSX-X) Ni Cr Co W Re Ta Al Mo Figure 4-47: Elemental se gregation plot based on due to decreasing W to 5.85 wt% and adding 1.6 wt% Mo.

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87 4.4.10. Tantalum and Aluminum Segre gation Behavior Interactions The former interactions were observed in three different combinations. The first was comparing LMSX-1 to LMSX-12. These alloys utilized an increase in the Ta concentration from 8.6 wt% to 11.2 wt%, coupled with a decrease in Al from 5.55 wt% to 5.00 wt%. The second comparison was LMSX-1 to LMSX-13. Here, the Ta was decreased to 6 wt% and the Al was increas ed to 6.15 wt%. The last comparison examined in this section was that of LM SX-12 to LMSX-13, in which the effect of varying Ta and Al can readily be seen. When comparing LMSX-1 to LMSX-12, the e ffects of substituting Ta for Al on the segregation behavior was determined. Re, W, Co, and Cr segregated to the dendritic region, and the magnitudes of their segregation co efficients were also in that order (from greatest to least). The segregat ion of Co increased slightly, but all the other elements that segregated to the dendrite core (Re, W, and Cr) had no observable effects in their segregation behaviors due to the substitution of Al for Ta. Ta, Ni, and then Al were shown to partition to the inte rdendritic region, with Ta exhibiting the greatest magnitude, and Al the smallest, and the segregation of Ta and Al increased (Ta more than Al). Ni exhibited a slight decrease in segregation from the substitution of Al for Ta. See Figure 4-48. The next comparison involved the substitution of Al for Ta using LMSX-1 and -13 (Figure 4-49). The segregation behavior of Re increased when Al was substituted for Ta, but Re still exhibited the most severe segr egation to the dendritic region. W had the same trend, but segregated less strongly than Re in both instances. Co still partitioned to the dendritic region, and showed only a very sl ight increase in segregation due to this

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88 change in chemistry. The substitution of Al for Ta resulted in the segregation of Cr changing from the dendritic re gion in LMSX-1, to the interd endritic region in LMSX-13. Ta, Ni, and Al all segregated to the inte rdendritic region, but to varying degrees. The magnitude of from the baseline alloy (from greates t to least) was Ta, Ni, and Al. But after the alloy was modified, this order ch anged. Ni and Ta switched, and Ni became the most heavily segregated of the three el ements. The segregation behavior of Ni increased more than any other element in this series. The segregation behavior of Al also increased, but not to the extent of Ni. The degree of segregation of Ta actually decreased. The final comparison was between LMSX12 and LMSX-13 (Figure 4-50). Due to the general linearity of the trends in the comparison betw een LMSX-1 and LMSX-12, the trends shown in this graph appear almost iden tical. All the trends are also duplicated. The only change was a slight decrease in th e segregation behavior of Cr from LMSX-12 to LMSX-13. 4.4.11. Tantalum and Aluminum Segregatio n Behavior with an Addition of Titanium Keeping with the same methodology as the pr evious section, in teractions between the alloys LMSX-1, -14 and -15 could be ex amined to determine the effect of other formers on the segregation behavior. LMSX -14 differs from LMSX-1 by a reduction in Ta from 8.6 wt% to 6.0 wt% and an additi on of 0.80 wt% Ti. The difference between LMSX-1 and -15 is LMSX-15 has 5.10 wt% Al and an addition of 0.80 wt% Ti. These alloys were compared in this way, and th en a final comparison between LMSX-14 and 15 was done.

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89 Normalized Partitioning due to an Increase in Tantalum and a Decrease in Aluminum-50.0 -40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 60.0112Alloy Ni Cr Co W Re Ta Al Figure 4-48: Elemental segregation plots based on due to increasing Ta to 11.2 wt% and decreasing Al to 5 wt%. Normalized partitioning due to a Decrease in Tantalum and an Increase in Aluminum-60.0 -40.0 -20.0 0.0 20.0 40.0 60.0 80.0113Alloy Ni Cr Co W Re Ta Al Figure 4-49: Elemental segregation plots based on due to decreasing Ta to 6.0 wt% and increasing Al to 6.15 wt%.

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90 Normalized partitioning due to Varying bothTa and Al-60.0 -40.0 -20.0 0.0 20.0 40.0 60.0 80.01213Alloy Ni Cr Co W Re Ta Al Figure 4-50: Elemental se gregation plots based on due to changing Ta and Al concentrations. Compilati on of Figures 4-48 and 4-49. The effect of adding Ti for Ta was ex amined by determining the segregation behaviors of LMSX-1 and -14 (Figure 4-51) As in previous results, the following elements segregated to the dendritic region : Re, W, Co, and Cr. The elements that segregated to the interdendritic re gion were Ta, Ni, Al, and Ti. The alloy modification caused a decrease in partitioning for Re (which segregated the most strongly), and increased the segregati on of W. The substitution of Ti for Ta also resulted in a slight increase in the segreg ation behavior of Co, and no observable change for Cr. For LMSX-1, Ta was the most segregated of the formers, but in LMSX-14 Ni was the most strongly segregat ing element. The value of for Ni was also more than that of Ta in LMSX-1. Essentially decreased for Ni (more negative) and increased for Ta (closer to zero). The segregati on of Al also increased slightly.

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91 The effect of substituting Ti for Al (LMSX-1 and -15) on the segregation behavior was slightly clearer than the previous compar ison (Figure 4-52). Re, W, Co, and Cr all segregated to the dendrite core regions. Re was the most segregated, followed by W, Co, and finally Cr. The elements segregating to th e interdendritic were Ta, Ni, Al, and Ti. The alloy modification (i.e. substituting Ti for Al) brought about a decrease in the segregation behavior of Re, a nd an increase in the degree of segregation of W, Co, and Cr, to about the same extent. Al did not change between these alloys. Ni decreased slightly indicating a slight increase in segregation, and Ta increased to the same value as Ni (both for LMSX-15). The partitioning of Ta decreased with this s ubstitution of Ti for Al. Finally, the effect of varyi ng Ta and Al at constant Ti was evaluated by examining alloys LMSX-14 and -15. All of the elements continued to segreg ate to the respective regions as specified in the two prior compar isons (Figure 4-53). Substituting Ta for Al resulted in the degree of Re segregation, and a decrease in segregation of W. Co and Cr both exhibited increased segregation, with Co exhibiting slightly great er segregation than Cr. As in most alloys, Re showed the greatest degree of segregation. Ni was generally the more segregated of the elements in the interdendritic region, but in LMSX-15, the degree of segregation fo r Ni and Ta were about the same. Ni exhibited a decrease in segregation (increase in when is negative), and Ta exhibited an increase in segregation (decrease in when is negative). A slight reduction in the partitioning of Al was observed in LMSX15, in comparison to LMSX-14. Finally, Ti partitioned to a greater degree in LMSX15 than in LMSX-14. Of all of the Ta values

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92 calculated in this inve stigation, the values de termined for Ta in LMSX-14 indicated the least amount of Ta segregation observed in this alloy series. 4.5. Scheil Analysis and Comparison To further check the validity of this an alysis, a Scheil analys is was done according to the method described by M. N. Gungor.36 For clarity, the Gungor methodology is identified in the following as Full analysis and the work in this study is identified as Short analysis. The LMSX-3 specimen was us ed for this test. Appendix D contains all pertinent data and graphs from this ev aluation. The full Sche il equation was not determined; however the general shapes of the curves were compared to examine the effectiveness of a much faster method of collecting the data. The Short analysis compares very well agai nst the Full analysis for Ni, Cr, Co and Al, (Figure 4-54 is shown for Cr) with the cu rves having the same shape, slope, and lying very close, if not on one another. The curv es for W and Re (Figure 4-55 is shown for Re) are also similar, but they do begin to diverg e or have a slightly greater slope than the curve for the other elements. The only curv e that exhibited a si gnificant difference was for Ta (Figure 4-56). Although there was one curve of seven that differed, the advantage of this is the time required to perform the entire test. The Full analysis required 12 hours to perform, and the Short analysis (which was the techniqu e use to evaluate segregation in all prior sections) took 5 hours.

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93 Normalized Partitiioning due to Decreasing Ta with an Addition of Ti-50.0 -40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 60.0114Alloy Ni Cr Co W Re Ta Al Ti Figure 4-51: Elemental se gregation plots based on due to decreasing Ta to 6.0 wt% and a Ti addition of 0.80 wt%. Normalized Partitioning due to a Decrease in Al and an Addition of Ti-50.0 -40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 60.0115Alloy Ni Cr Co W Re Ta Al Ti Figure 4-52: Elemental se gregation plots based on due to decreasing Al to 5.10 wt% and a Ti addition of 0.80 wt%.

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94 Normalized partitioning of Varying Amounts of Tantalum and Aluminum with an Addition of Titanium-50.0 -40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 60.01415Alloy Ni Cr Co W Re Ta Al Ti Figure 4-53: Elemental se gregation plots based on due to changing Ta and Al concentrations with a Ti addition. Compilation of figures 4-51 and 4-52. LMSX-3 Cr Scheil Comparison0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.10.20.30.40.50.60.70.80.91 vol%wt% Cr Full Short Figure 4-54: Scheil curve comparison fo r Cr done by two different techniques.

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95 LMSX-3 Re Scheil Analysis0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 00.10.20.30.40.50.60.70.80.91 vol%wt% Re Full Short Figure 4-55: Scheil curve comparison fo r Re done by two different techniques. LMSX-3 Ta Scheil Analysis0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 00.10.20.30.40.50.60.70.80.91 vol%wt% Ta Full Short Figure 4-56: Scheil curve comparison fo r Ta done by two different techniques.

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96 4.6. Verification of Applicability of Analysis The analysis described in this investiga tion was done on an as-cast specimen of CMSX-4 to compare values returned for both k and Results for this portion of the study are in Table 4-4. When comparing the values for and k for CMSX-4, there is perfect agreement in the direction of elemental pa rtitioning. Values of kB greater than unity indicate partitioning of elements to the dendritic core regions. Values of greater than zero indicate this also. For va lues of k less than unity, there is segregation to the interdendritic region. When is used, segregation to the interdendritic region will be less than zero. All of the elemen ts in CMSX-4 show agreement between the two techniques. The magnitudes of segregation were somewhat different for the trace elements Mo and Ti in CMSX-4. Again this use of is based on the start and stop poi nts. The convention used in this experiment was to start and stop at de ndrite cores. Using the dendrite cores as starting and stopping points has dend ritic segregation occurring if is greater than zero. If the interdendritic region is use d, dendritic segregation occurs if is less than zero. To continue with the verification, Scheil curves were prepared for CMSX-4 so that they could be compared with similar curves44 for CMSX-4. The partitioning direction for these curves was based on the k results found in Table 4-4. The data and Scheil curves for CMSX-4 are contained in Appendix D.

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97 Table 4-4: Comp arison of kB and for CMSX-4. Ni Cr Co Mo W Re Ta Al Ti Dendritic 63.08 6.2510.520.696.064.433.47 5.150.69 Interdendritic 65.57 7.379.220.723.551.296.20 6.711.45 k'B 0.96 0.85 1.14 0.96 1.71 3.43 0.56 0.77 0.48 -6.86 -5.01 4.39 -0.76 14.13 16.00 -11.81 -6.20 -3.90

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98 CHAPTER 5 DISCUSSION There is a significant amount of literature on the effect of composition on the properties (i.e. creep, fatigue, strengthening, etc.) of supera lloys. However, due to the complexity of the system, with twelve to fifteen alloying elements in a typical superalloys4-6,30,36, a significant amount still remain s unknown. Elemental interactions and the complex problems w ith segregation and diffusion are prevalent throughout the superalloy system. As noted above, superalloys are made up of twelve to fifteen different elements added to nickel, which is the most common base element. The typical additions to the base element are Al, Cr, Co, W, Re, Ti and Ta. There are other additions that are relatively low levels and have been ignored for the purposes of discussion (i.e. Hf and B). Ni and Al, when present together in the appropriate amount form the matrix. This occurs in the vicinity of Ni15Al in the Al-Ni binary diagram14, but commonly, a superalloy only contains about 55 60 wt% Ni and about 4 -6 wt % Al. The remaining 40 45 wt% is made up of all the other alloying elements, and each element has a different melting temperature. Elements su ch as Re, W, and Ta all have very high melting temperature, are very dense, and diffuse slowly, but Cr, Co, and Ti have relatively low melting temperatures have lower densities, and di ffuse at different rates. These differences cause the elements to be distributed unevenly throughout the alloy during solidification, and in some extreme circ umstances, an undesirable phase if formed due to localized enrichment. If the pattern s for the segregation of the elements used in these alloys are known, improved alloys compositions can be developed.

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99 Heat treatments are often used to reduce or eliminate se gregation from the as-cast microstructure. An alloy that is less segr egated (more homogeneous) requires less time to heat treat (solution) to re duce segregation. The purpose of heat treatments is to evenly disperse all of the elements in the alloy and develop an optimized microstructure so that more uniform and better properties will be obser ved in the alloy. This local enrichment of elements forming in the as-cast structure can also lead to deleterious phases such as , and laves phases. To eliminate segregati on in the alloy, the elements must diffuse through the matrix until they are well disp ersed. Diffusion is a thermally activated process; higher temperature equals shorter time, but some incipient melting may occur. However, lower temperature heat treatments require longer times, and the alloy may still be segregated, unless sufficient time is allo wed. Shorter and lower temperature heat treatments are desired by industry since the heat treatment costs will be reduced. The temperature is governed by the difference between the solvus and solidus temperatures, or the heat treatment window. Third generation superalloys (2 at% Re) are currently used in a variety of applications. These are some of the most h eavily alloyed superalloys and contain nearly 15 wt% of the refractory elements, Re, Ta, and W. With the addition of these refractory elements, segregation can cause problems dur ing casting. CMSX-10 is a third generation superalloy used to make airfoils for some of the highest temperature applications. The chemistry of CMSX-10 is listed at the bottom of Table 3-1. Due to the alloy chemistry, the solvus is very high (over 1350C), and the solidus is only 30C higher.16 Since these dense refractory elements diffuse slowl y, the total time for solution heat treatment for an alloy like CMSX-10 can be nearly 50 hours. This makes heat treating very

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100 difficult, and expensive. Because of these l ong and expensive heat treatments, the desire to understand how the elements partition b ecomes important because it could lead to shorter heat treatment times. The baseline alloy LMSX-1 was developed to have an approximate volume fraction of 55 60% and have good microstruc tural stability (not form topologically close packed (TCP) phases on casting or thr oughout service life). The chemistry of LMSX-1 is based on two commercial third ge neration alloys, CMSX-10 and Ren N6. The other seventeen alloys were developed to examine the effect of the additions on strength, stability, solvus, etc. The composition of LMSX-1 and the other seventeen model alloys is contained in Table 3-1. Currently, partitioning is determined by ratioing the composition of an element between the dendrite core region and the interdendritic region11,16,37-39 (equation 1-1). This calculation produces what is knows as the partitioning coefficient k. k readily indicates if an element segregat es to the dendrite core (k > 1. 00) or to the interdendritic region (k < 1.00), but k does not provide an estimate of the inte ractions between the elements in the alloy. To begin to ev aluate the interactions, the curvature was used of the compositions along a line scan in this study. The minimum or maximum point on the line scan curves was the position was determined, and represents the maximum degree of segregation along the line scan. 5.1. Primary Dendrite Arm Spacing The primary dendrite arm spacing (PDAS) was calculated for the eighteen model alloys (Table 4-1). The expected di stance between the de ndrite cores was 300 mm. The values calculated by the twenty fiel ds of view returned ranged from 253.5 m

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101 (LMSX-3), to 381.9 m (LMSX-9). The PDAS was also calculated from the line scans using the average of the three scans done. The PDAS values from the lines scans ranged from 174.7 m (LMSX-17) to 367.9 m (LMSX-9). The information on PDAS is included in this study for reference only, a nd both methods yielding similar results. When comparing both methods of measur ing the PDAS, the only measurements that were greater than one standard devi ation from the mean were those for LMSX-10 and -17. Six of the measurements were within 20 m of one another (LMSX-3, -9, -11, -13, -15, and -18). Of the remain ing ten alloys, eight were with 50 m of one another. The only two alloys that had a difference of greater than 70 m were LMSX-1 and -2. The standard deviations for the PDAS m easurements were larg e (typically around 70 m) and this is probably due to the heterogeneous nature of the solidif ication structure and differences in solidification rates in local regions of that specimen. 5.2. Partitioning Coefficient and Segregation This section describes the reasoning a nd methods for determining the partitioning coefficients and then continues on to eval uate the eleven alloy systems examined. 5.2.1. Comparison of k and Techniques for Examining Segregation The idea for the use of a different an alytical technique for explaining the segregation, stemmed from the an alysis of the very different behaviors observed in the line scans for Ni and Ta in LMSX-9, -10, 1, and -11 (Figure 5-1 and 5-2). When the partitioning coefficient k was calculated from the EMPA data, the raw data for Ni exhibited a greater degree of segregation in LMSX-11 than Ta, but Ta was more heavily segregated in LMSX-9, -10, an -1. The kNi and kTa did not indicate this trend

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102 (Table 4-2). The curvature of the trendline, was then used to better describe the segregation behavior of the partitioni ng of the elements in the system. The following is an example to illustrate the difference in k and Assume the segregation of two elemental additions, to a Ni-base superalloy, A (7.5 wt%) and B (2.5 wt%), is measured using a line scan. The da ta from the line scans behaves in a parabolic manner similar to the elements described in this study (Figure 5-3). k would be calculated in accordance with equation 1-1, a nd would be equal to 4 for both elemental additions and both segregate strongly to the de ndrite core. A more scientific method of determining the partitioning would be by comp aring the extreme values to the expected value (C/C0). Given that the average value in Figure 5-3 (A: 7.50, B: 2.50), a similar result also occurs. Both elements would have the same value for segregation of 1.6. However, when the data from the line scan is examined, element A segregates more strongly than element B. The trendlin es were determined for element A (38.571 x2 39.857 x + 13.286) and element B (12.857 x2 13.286 x + 4.4286), and from these, the was calculated to be 77.14 and 25.17 for elements A and B respectively. Those values of indicate that the elements do still segregat e to the dendrite core, and also which element segregates more strongly based on th e elements compositional gradient. The data generated in this study was combin ed with literature reports to perform a similar comparison of real data. Th e k data acquired in this study (kB) was compared to the k data compiled by F. Fela (kA) (Table 4-2), and compared to trends found in literature4. The technique used in this study ag reed well with prio r and some published work (when alloys of similar elemental compos itions are examined). This indicated that

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103 Plot or Ni Segregation Due to Varying Re Content with Normalized PDAS50.00 52.00 54.00 56.00 58.00 60.00 62.00 64.00 66.00 68.00 70.00 00.10.20.30.40.50.60.70.80.91 Normalized PDASwt% Ni LMSX-1 LMSX-9 LMSX-10 LMSX-11 Figure 5-1: Ni segregation pl ot for LMSX-9, -10, -1, and -11. Trendlines were added to show degree of segregation of Ni obs erved as the Re content was increased. Plot of Ta Segregation Due to Varying Re Content with Normalized PDAS0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 00.10.20.30.40.50.60.70.80.91 Normalized PDASwt% Ta LMSX-1 LMSX-9 LMSX-10 LMSX-11 Figure 5-2: Ta segregation plot for LMSX-9, -10, -1, and -1 1. Trendlines were added to show degree of segregation of Ni obs erved as the Re content was increased.

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104 k' ComparisonElement A: y = 38.571x2 39.857x + 13.286 Element B: y = 12.857x2 13.286x + 4.42860 2 4 6 8 10 12 14 00.10.20.30.40.50.60.70.80.91 Normalized PDASwt% element A B Poly. (A) Poly. (B) Figure 5-3: Example sh owing data for k and from two idealized elemental segregation profiles based on a normalized PDAS. Th e equations for each trendline are indicated on the graph. the technique of using line scans did not offset the data collected a ppreciably and did not produce erroneous results. The data was next compared to the kB data and trends were compared. The trends for kB and were nearly identical (Table 4-3) The only differences occurred in the elements that exhibited only a slight segregation preference. Therefore, the data that was obtained, fit the kB data, and agreed with kA data from a previous study. kB and values are listed in Table 4-3. The use of has two additional benefits. Since the composition is based on 100%, all of the trendline constants sum up to 100. When the second derivative is taken, the curvatures should sum to zero (or close to zero). This indicates ther e are no errors in the

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105 data used for the analysis; i 0, where i is one of the el ements in the alloy. This requirement for the s to sum to zero is due a function of the mathematics used. Additionally, overall effects of alloy segregation can be identified visually (from the graphs as indicated by the overall changes in of in the appropriate graphs) or mathematically ( ij, where i is one of the elements in alloy j). Whichever ij is at a minimum for a set of alloys being comp ared, that alloy exhib its the least overall amount of segregation of those alloys comp ared. The complete list of all of the mathematical sums of k are listed in Table 51. The alloys in Table 5-1 are listed in order of lowest i to highest i Table 5-1: i for the eighteen model alloys and CM SX-4 listed in order from lowest to highest. Alloy i Alloy i Alloy i LMSX-9 57.07 LMSX-16 152.57 LMSX-18 202.24 CMSX-4 69.07 LMSX-14 153.72 LMSX-17 222.65 LMSX-7 108.71 LMSX-15 158.29 LMSX-11 249.41 LMSX-8 128.99 LMSX-12 159.78 LMSX-4 132.11 LMSX-3 173.00 LMSX-10 140.75 LMSX-2 178.25 LMSX-5 147.01 LMSX-13 186.02 LMSX-1 150.88 LMSX-6 189.83 5.2.2. Cobalt Effects The effect of Co addition on solidification and segregation were examined using LMSX-1 (12.2 wt% Co), -2 (8 wt% Co), and -3 (4 wt% Co). LMSX-1 is based on the chemistry of Ren N6 (12.5 wt% Co), and LMSX-3 is based on CMSX-10 (4 wt% Co). All three of the alloys were examined in the as-cast condition to investigate each elements segregation pattern and then compar ed against the varying Cr concentration to evaluate the effects.

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106 Figures 4-10 and 4-11 contain the kB graphs for Cr, and Figure 4-38 contains the graph for the Co additions. Both sets of data and graphs show similar trends. In all cases, as the amount of Co is increased in th e alloy, the elemental pa rtitioning decreased. kRe, kW, kCo, and kCr were all greater then one i ndicating that these elements partitioned to the dendrite core. The k curves indicate a large decrease in the partitioning of Re due to the addition of 8 wt% Co, and then there is no further change as the Co content is increased. The k curve for W indicated a decrease in segregation as the Co content was increased to 8 wt% Co, but to a lesser degree than Re, and kW did not change further with increasing Co content. kCo and kCr exhibited little change due to increasing Co concentrations. The partitioning coefficients for Ni, Ta, and Al were all less then 1.00, and therefore these elemen ts were observed to segregate to the interdendritic region. kTa increased from the 4 wt% Co to 8 wt% Co concentration, and then did not change further as more Co was added to the alloy. kAl also increased, but from the 4 wt% Co to the 12.2 wt% Co cont ent alloy, and at a constant rate. The partitioning coefficient for Ni, kNi, decreased slightly at Co cont ents greater than 8 wt%. The value trends were similar to the kB trends. Re decreased slowly from the 4 wt% Co to the 8 wt% Co concentration, a nd then decreased more rapidly as Co concentration was increased to the 12.2 wt%. W exhibited a constant decreasing trend as the Co content was increased 4 wt% Co to 12.2 wt% Co. The Co increased as the Co content was increased from 4 wt% up to 8 wt%, and then remained constant up to 12.2 wt% Co. This increase in Co segregati on can be explained due to the amount of increasing amounts of Co in the Ni matrix. Cr did not exhibit any change due to increasing Co concentrations. The curvature va lues indicated that Re, W, Cr, and Cr all

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107 segregated to the dendrite cores. The Ta and Al were not visibly affected when the Co concentration was increased from 4 wt% to 8 wt%. However, when the Co content was increased further, both Ta and Al decreased (became less negative). Ni segregation increased ( Ni decreased, became more negative) from 4 wt% Co to 8 wt% Co. As the Co content was further increased, Ni increased slightly, but still exhibited more segregation then originally at 4 wt% Co. This can be attributed to Co substituting for Ni in the lattice. Overall, as the Co content was increa sed from 4 wt% to 12.2 wt%, segregation decreased in both analyses, k and (Based on Figure 4-24). Therefore, Co additions are a viable method to decrease the segregati on of the heavy elements Re, W, and Ta. In addition to this, other work on this alloy indicated similar results.16,38,43 5.2.3. Chromium Effects The effect of Cr additions on solidification and segregation were examined using LMSX-5 (2.1 wt% Cr), -1 (4.1 wt% Cr), and -4 (6.15 wt% Co). All three of the alloys were examined in the as-cast condition to investigate each elements segregation pattern and then compared against the varying Cr concentration to evaluate the effects. Figures 4-8 and 4-9 contain the kB graphs for Cr, and Fi gure 4-39 contains the graph for Cr. Both sets of data and graphs show similar trends that as the amount of Cr is increased in the alloy, the elem ental partitioning decreases. kA,Cr and kB,Cr for LMSX5 indicated different segregat ion directions, but this wa s the only observation where kA and kB did not agree. kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores. The partitioning coefficient curves, k, indicated an increase in the

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108 partitioning of Re as the Cr content was in creased from 2.1 wt% to 4.1 wt%. When the Cr content was increased from 4.1 wt% to 6.15 wt% exhibited no further effect on the segregation of Re. kW decreased slightly as Cr conten t was increased. The segregation behavior of Co and Cr both increased as the Cr composition was increased form 2.1 wt% Cr to 6.15 wt% Cr, with Co segregating to a slightly greater degree than Cr. kTa, kAl, and kNi were all less than 1.00 (indicating segrega tion to the interdendritic region). Ta was the most heavily segregated of the elements partitioning to the interdendritic region. As the Cr content was increased, kTa continued to decrease (approach zero) indicating increasing segregation. Increa sing the Cr content from 2.1 wt% to 4.1 wt% had no affect on kAl, but as the content was furt her increased to 6.15 wt%, kAl began to increase (approach 1.00) indicating less segregation. The segregation of Ni was not affected by varying the Cr content in the alloys. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). The increasing the Cr c ontent from 2.1 wt% to 4.1 wt% had no observable effect on Re, but as the Cr content was furt her increased to 6.15 wt%, the segregation of Re decreased. W exhibited a constant decreasing trend due to the increased Cr content. The degree of Co segr egation increased slight ly as the Cr content was increased in the alloy. Cr increased slightly as Cr content was increased. Cr partitioned to the interdendritic region in LMSX-5 (2.1 wt% Cr), and then was observed to partition back to th e dendrite core for higher Cr concentrations. Al also increased (became less negative) as the Cr content was increased. Ni was observed to segregate to the interdendritic regi on more severely in LMSX-5 (2.1 wt% Cr) than Ta, but as the Cr concentration was increased, Ta began to segregate more strongly than Ni. The Ni

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109 exhibited an increasing trend (became less negative) as the Cr content increased. The segregation behavior of Ta, Ta, increased with increasing Cr content to 4.1 wt% Cr. As the Cr concentration was increased further, Ta did not change. Overall, as the Cr content was increase d from 2.1 wt% to 6.15 wt%, segregation decreased somewhat in both analyses, k and (determined mathematically: i4 = 147, i1 = 150, and i5 = 132). Therefore, Cr addi tions are a viable method to decrease the segregation of the heavy elements Re, W, and Ta, but Cr has been identified as an element that decreases the solvus temperature, and decreases alloy stability44. Based on this information, the use of Cr to d ecrease segregation would have to be balance with other necessary properties (i.e. microstructural stab ility or strength).16 5.2.4. Rhenium Effects The effect of Re additions on solidification and segregation was examined using LMSX-9 (0 wt% Re), -10 (2.95 wt% Re), -1 (5.9 wt% Re), and -11 (8.7 wt% Re). All four of the alloys were examined in the as-cast condition to investigate each elements segregation pattern and then compared ag ainst the increasing Re concentration to evaluate the effects. Figures 4-11 and 4-12 contain the kB graphs as a function of Re content, and Figure 4-40 contains the versus Re content plot. Both sets of data and graphs show similar trends that as the am ount of Re is increased in th e alloy, the elemental partitioning increases. kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores, with the exception of kCr in LMSX-9 which was observed to partition slightly to the interd endritic region. The partitioning coe fficient, k, when plotted versus

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110 Re content indicated an increase in the pa rtitioning of Re, as the Re content was increased. The increase in Re segregati on with increasing Re content was the most severe increase in partitioning observed in these alloys. kW was unaffected by the 1 and 2 at% additions of Re, but increased slightly with the addition of the third 1 at%. The segregation behavior of Co was unaffected by the increase in Re content. Cr, as was stated, segregated to the inte rdendritic region in LMSX-9 (kCr < 1.00), but when Re was added, Cr began to segregate slight ly to the dendr ite core, but kCr did not increase further until the final 1 at% Re was added, and then kCr increased slightly. kTa, kAl, and kNi were all less than 1.00 (indicating segregation to the interdendritic re gion), except for kNi in LMSX-9 exhibited a weak tendency to segreg ate slightly to the dendrite core. Ta, Al, and Ni all exhibited trends of increasing segregation as the Re content was increased. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). Re was the most strongly segregated element ( Re the largest) when only 1 at% was added in LMSX-10. As the Re content was increased further, Re increased in a parabolic manner. The degree of segreg ation of W decreased slightly as the concentration of Re was increased. Co increased initially with the addition of 2.95 wt% Re, but then only increased slightly mo re as the Re content was increased. Cr indicated that Cr segregated to the interdendritic regi on in LMSX-9 (0 wt% Re). With the addition of 1 at% Re, Cr began to segregate to the dendrite core, but was not affected with the further additions of Re. The addition of a third 1 at% Re caused a slight increase in Cr. With no Re present, the curvature for Ni ( Ni) indicated that Ni segregated to the dendritic region. As Re was added to the alloy, Ni began to decrease (become more negative), and therefore segregat e more to the interdendritic region. When the Re content

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111 was at 8.9 wt% (LMSX-11), Ni was observed to be the most heavily segregated element of those that segregated to th e interdendritic region. At lo wer Re levels, Ta was the most heavily segregated element that segregated to the interdendritic region, and was the most heavily segregated element in the model alloys LMSX-9 and -10. When the Re content was increased, Ta decreased with the first addition, and indicated no further effects due to increasing Re content. Al had no observable change due to increasing Re content until the third 1 at% Re was added (LMSX-11). With the final addition of 1 at% Re, Al decreased slightly. Overall, as the Re content was increa sed form 0 wt% to 8.9 wt%, segregation increased in both analyses, for the partit ion coefficients, k, and the curvature, (Figure 4-40). Re is a beneficial elemental addition, but increasing the Re c ontent in these alloys increased the segregation (kB and ) of each element in each alloy. When Re is considered for alloying of a superalloy, the me rits it brings must be balanced with the segregation problems that are also present. These segregation problems can lead to microstructural instabilities and extended solution heat treatments.16 5.2.5. Tungsten Effects The effects of increasing the W concentr ation on solidification and segregation were examined using LMSX-1 (5.85 wt% W) and -6 (8.6 wt% W). These alloys were examined in the as-cast conditi on to investigate each elemen ts segregation pattern as a function of W concentration to evaluate the effects. Figures 4-13 and 4-14 contain the kB graphs as a function of W content and Figure 4-41 contains the graph for W. Both sets of da ta and graphs indicate that the partitioning increases slightly as the amount of W is increased in the alloy. However,

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112 there was a discrepancy between kB and when examining the partitioning of Re. kRe was observed to decrease with increasing W content, while Re was observed to increase slightly with increasing W cont ent. This difference is being attributed to the scatter that is inherent when k is determ ined, and is corrected for using kRe, kW, kCo, and kCr were all greater than one, indicating that these elements segregateto the dendrite co res. As was stated, kRe exhibited a decreasi ng trend as the W content was increased. This is surprising since both W and Re segregate to the dendrite core, and both are very dense elements. kW indicated that W was segregating more as the W content was increased. kCo and kCr had no clear trend in their segregation behaviors as the W concentr ation was increased. kTa, kAl, and kNi were all less than 1.00 (indicating segregation to th e interdendritic region). Ta and Al both exhibited an increase in segregation due to the increase in W content. The segregation of Ni was observed to decrease slightly with th e increased concentration of W. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). Re was the most heavily segregated element, and when the W content was increased, Re increased slightly, indicating a s light increase in the segregation behavior of Re. The segregation of W and Co also exhibited an increasing trend as W content was increased in the alloy ( W increased more than Co). Cr segregation increased slightly due to an increase in W content. Al and Ni both became more negative (increasing segregation) as the concentration of W increased. Ta was unaffected by the increase in W. Ta was more strongl y segregated in LMSX-1 (5.85 wt% W) than Ni, but Ni became more segregated than Ta in LMSX-6 (8.6 wt% W).

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113 Overall, as the W content was increased from 5.85 wt% to 8.6 wt%, segregation increased slightly in both analyses, k and (Based on Figure 4-41). W, like Re, is a beneficial elemental addition for solid solu tion strengthening. But increasing W content also increases the partitioning of all the elements present in the alloy, which can lead to longer heat treatment times to remove the segr egation in these alloys. Work reported by F. Fela on this alloy indicated similar results.16 5.2.6. Tungsten Effects with an Addition of Molybdenum The effects of an increasing W concentra tion with a Mo addition on solidification and segregation were examined using LMSX -7 (3.1 wt% W, 1.6 wt% Mo) and -8 (5.85 wt% W, 1.6 wt% Mo). Both of the alloys were examined in the as-cast condition to investigate each elements segregation patte rn and then compared as a function of W concentration to evaluate the effects. Figures 4-15 and 4-16 contain the kB plots for increasing W content with a Mo addition, and Figure 4-32 contains the versus W content with a Mo. Both sets of data and graphs show similar trends that as the amount of W is increased with an addition of Mo, the elemental partitioning was observed to increase slightly. kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores. Re exhibited an increasing de gree of segregation when the W content was increased. The increase in W from 3.1 wt% to 5.85 wt% caused a sm all increase in the segregation of W. The segreg ation of Co was not affected by an increase in W with an addition of Mo. Cr segregation was obser ved to decrease as the W content was increased. kTa, kAl, kMo, and kNi were all less than one, indicating segregation to the interdendritic region. The segr egation of Ta, Mo, and Ni a ll increased as the W content

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114 was increased with the addition of 1.6 wt% M o. The segregation of Al did not change when the W concentration was increased and Mo was added. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). The variations in W content in LMSX-7 and -8 had little observable change in Re, Co, Mo, and Ta. Of the elements segrega ting to the dendritic region, W was the only element that exhibited an incr ease in segregation was increased from 3.1 wt% W to 5.85 wt% W. Ni decreased as Ni segregated more due to the increasing W content. Al also exhibited an increase in segregation when the W content was increased from 3.1 wt% to 5.85 wt% and 1.6 wt% of Mo was added. Overall, as the W content was increase d from 3.1 wt% to 5.85 wt% and 1.6 wt% with a constant Mo concentrati on, the segregation incr eased slightly in the k analysis and increased more severely in the analysis (Based Figure 4-42). The increase in segregation caused by the incr easing W content and with a Mo addition may result in extended heat treatment time. 5.2.7. Molybdenum Effects The effect of an addition of Mo on solidification and segregation were examined using LMSX-1 (0 wt% Mo), and -8 (1.6 wt% Mo). Both of theses alloys were examined in the as-cast condition to investigate each elements segregation pattern and then compared as a function of Mo concentration. Figures 4-17 and 4-18 contain the kB versus Mo content, an d Figure 4-43 contains the versus Mo content. As Mo is added to the alloy, th e partitioning decreases, and both sets of data and gra phs show similar trends.

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115 kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores. Re was the most severely se gregated element, and showed the greatest decrease in segregation as Mo was added. The segregation of W and Co both decreased as Mo was added also. kW was greater than kCo. The addition of Mo had no visible effect on the segregation of Cr. kTa, kAl, kMo, and kNi were all less than one, indicating segregation to the interdendr itic region. Ta segregated the most severely, followed by Mo, Al, and then Ni. The addition of Mo caused the most significant decrease in the segregation of Al to decrease the most. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). All of the elements except Cr, Co, and Al e xhibited decreasing segregation due to the addition of 1 at% Mo. Cr and Co both increased slightly indicating a slight increase in segregation with the additiona l Mo content. The addition of 1.6 wt% Mo had no affect on the segregation behavior of Al ( Al was constant). Overall, when 1.6 wt% Mo was added to th e baseline, the segregation decreased in both the k and analyses (Based from Figure 4-43). The decrease in segregation caused by the addition of Mo may result in a d ecrease in heat treatm ent time. Previous reports done by F. Fela on this alloy indicated similar results.16 This also provides some insight into why Ren N6 ha s an addition of 1.1 wt% Mo. 5.2.8. Ruthenium Effects The effect of a Ru addition on solidificat ion and segregation was examined using LMSX-1 (0 wt% Re), -16 (1.6 wt% Ru), and -1 7 (3.2 wt%). All three of the alloys were examined in the as-cast condi tion to investigate each elem ents segregation pattern and then compared against as a function of Ru concentration.

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116 Figures 4-19 and 4-20 contain the kB versus Ru content, and Figure 4-44 contains the versus Ru graph. Both sets of data and gr aphs show similar tre nds, and in general, the segregation behavior of the alloying elemen ts increased as Ru content is increased in the alloy. kRe, kW, kCo, kRu, and kCr were all greater than one indicating segregation to the dendrite cores. The add ition of 1 at% (1.6 wt%, LMSX-16) Ru had no affect on the segregation of Ru. However, when the second 1 at% (LMSX-17) Ru was added, Re exhibited a very large increas e in degree of segregation. W and Cr both exhibited an increase in segregation as the Ru content wa s increased from 0 wt% to 3.2 wt %. The effect of the Ru addition was more pronounced in the degree of segregation of Cr than W. Co exhibited no change in segregation as th e Ru concentration was increased from 0 wt% to 3.2 wt%. The segregation of Ru itself decreased slightly as the Ru content was increased from 1.6 wt% to 3.2 wt%. kTa, kAl, and kNi were all less than one, indicating segregation to the interdendr itic region. The segregation behavior of Ta, like Re, was unaffected by the addition of 1 at% Ru. But when the second 1 at% Ru was added to the alloy, Ta exhibited a large increase in segrega tion. The increased Ru content affected the segregation of Al when the Ru content wa s increased from 1.6 wt% to 3.2 wt%. Increased Ru content had no observable eff ect on the segregation behavior of Ni. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). The addition of 1 at% ( 1.6 wt%) Ru had no affect on the for all the elements ( Ta was observed to decrease to a lower value than Ni, but this was attributed to error), except Al, which incr eased slightly. The addition of a second 1 at% Ru (for a

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117 total of 2 at % or 3.2 wt%), caused an incr ease in the segregation of all elements examined. Overall, Ru has no observable effect on th e segregation behavior when 1.6 wt% is added. However, increasing the Ru concentr ation further causes large increases in the segregation of the elements in the alloy (d etermined visually from Figure 4-30). Since addition of 1 at% Ru does not change the se gregation behavior, this addition may be useful in further alloy development. With 3.2 wt% Ru content, the segregation increases substantially. This could lead to extended h eat treatment times and/ or other segregation issues due to localized concentrations of elements unless the alloy is properly heat treated. Previous work by F. Fela on this alloy indicated similar results16 as well as work done by H. Harada and collegues.29 5.2.9. Palladium Effects The effect of an addition of Pd on solidification and segregation was examined using LMSX-1 (0 wt% Pd) and, -18 (1.7 wt% Pd). Both of these alloys were examined in the as-cast condition to investig ate each elements segregation pattern as a function of Pd concentration. Figures 4-21 and 4-22 contain the kB vs.Pd graphs, and Figure 4-45 contains the vs. Pd graph. Both sets of data and graphs show similar trends, and in general, as the amount of Pd is increased in the a lloy, the elemental partitioning increases. kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores. The addition of 1.7 wt% Pd cau sed increases in the segregation behaviors of Re, W, Co, and Cr. Re was affected th e most by the addition of 1 at% Pd, followed by W. The segregation of Co and Cr both increas ed by about the same degree as Pd content

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118 was increased. kPd, kTa, kAl, and kNi were all less than one, indicating segregation to the interdendritic region. Pd itself exhibited the largest degr ee of segregation when it was added to the alloy. Ta segregated more than Al or Ni, but the degree of segregation of Al increased more than Ta due to the increased the Pd content. Due to the increase in Pd content, Ni exhibited a sli ght decrease in segregation. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). The for Re, W, Co, and Cr all increa se as Pd content is increased. Re had the largest increase followed by Co, kW, and then Cr. Ta and Ni were largely unaffected by increasing Pd conten t, and Ta segregated more th an Ni. The segregation of Al increased as the Pd content wa s increased form 0 wt% to 1.7 wt%. Pd was observed to be less than Al, and greater than Ni (Pd segregated more than Al, but less than Ni). As the Pd content of the alloys was incr eased, there was an increasing degree of segregation (Based on Figure 4-45). The only el ements that exhibited significant changes were Re, Co, and Al. Heat treating alloys that contain an addition of Pd may require extra time to cause the slow diffusing elements (i.e. Re, W) to become evenly distributed throughout the microstructure. Previous work by F. Fela on this alloy indicated similar results16 as well as in published literature.29 Pd has been reported to increase the surface stability of superalloys and could possible bo lster the corrosion resistance of the base alloy. Current work has pointed to the pl atinum group metals (PGM), including Pd and Ru being effective solid soluti on strengtheners and could be us eful as alloying additions. 5.2.10. Tungsten and Molybdenum Effects The effect of substituting Mo for W on solidification and segregation was examined using two different combinations of alloys: LMSX-1 (5.8 wt% W, 0 wt% Mo),

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119 -7 (3.1 wt% W, 1.6 wt% Mo), and LMSX-6 (8.6 wt% W, 0 wt% Mo), -8 (5.85 wt% W, 1.6 wt% Mo). Both combinations of these a lloys were examined in the as-cast condition to investigate each elements segregation pa ttern and examined as a function of alloy content. Figure 4-24 (4-25) contains the kB graph for substituting 1 at% Mo for 1 at% W for LMSX-1 and-7 (LMSX-6 and -8). Figure 4-46 (4-47) contains the graph for substituting 1 at% Mo for 1 at% W for LMSX-1 and -7 (LMSX-6 and -8). Both sets of data and graphs show similar trends, and in general, as Mo is s ubstituted for W, the segregation in the a lloy decreases. Since the trends are identical in Figur es 4-24 and 4-25, only figure 4-24 will be discussed. kRe, kW, kCo, and kCr were all greater than on e, indicating segregation to the dendrite cores. Re, W, and Co all exhibi ted decreasing degrees of segregation when 1 at% Mo was substituted for 1 at% W, while Cr e xhibited a slight increase in the degree of segregation. kTa, kAl, kMo, and kNi were all less than one, i ndicating segregation to the interdendritic region. Ta, Al, and Ni all exhi bited decreasing segregation when 1 at% Mo was substituted for 1 at% W. Mo segreg ated more than Ni, but less than Al. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). Unlike k graphs, there were some differences in the graphs, but this is attributed to the 8.6 wt% W in LMSX-6 (Figure E-2)and will be discussed when the graphs for LMSX-1, -7 and LMSX-6, -8. The substituting of 1 at% Mo for 1 at% W caused the segregation behavior of all the elements to decrease. The substitution of 1 at% Mo for 1 at% W decreased the overall segregation in the alloys (Based on both Figures 4-24 and 4-25) possibly making heat treatment easier.

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120 5.2.11. Tantalum and Aluminum Effects The effects of the formers Ta and Al were investigated. The model alloys for these experiments were LMSX, -12 and -13. LMSX-1 contained 8.6 wt% (3 at%) Ta and 5.55 wt% (13at%) Al. The chemistry of LM SX-12 had an increase of 1 at% Ta (to 3 at%, or a total of 11.2 wt%) and a decrease of 1 at% Al (to 12 at%, or a total of 5.0 wt%). LMSX-13 had Ta decreased by 1 at% (to 2 at %, or 6 wt%) and Al was increased by 1 at% (to 14 at%, or 6.15 wt%). These combinati ons were chosen to maintain a constant volume fraction of 55%. 5.2.11.1 Effect of increased tantalum with decreased aluminum The effects of substituting 1 at% Ta for 1 at% Al on solidification and segregation were examined using LMSX-1 and -12. These two alloys were examined in the as-cast condition to investigate each elements segrega tion pattern as a function of alloy content. Figure 4-26 contains the kB graph for substituting 1 at% Ta for 1 at% Al, and Figure 4-46 contains the graph for substituting 1 at% Ta for 1 at% Al. The graph for kB indicates that substituting 1 at% Ta for 1 at% Al reduced the segregation but the graph for indicates a slight increase in segregation due to this alloy modification. The differences in the graphs are from the effects of Re and Ta, but the differences are slight and are considered errors from sampling. kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores. kRe was the only one of these elements that exhibited a decrease in segregation due to substitution of 1 at% Ta for 1 at% Al. The change in segregation behaviors of W and Co were negligible wh en substituting 1 at% Ta for 1 at% Al. The segregation of Cr increase d slightly for this change in alloy chemistry. kTa, kAl, and kNi

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121 were all less than one, indicating segregation to the interdendritic region. When 1 at% Ta was substituted for 1 at% Al, the segregation of Ta decreased, as well as the segregation of Ni, but to a lesser degree. This modificat ion to the alloy chemistry had no appreciable effect on the segregation of Al. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). The segregation behaviors of Ta Co, and Al increased when 1 at% Ta was substituted for 1 at% Al. The segrega tion for Re, and Ni both decreased slightly when the alloy chemistry was modified by substituting Ta for Al. This substitution had no effect on the segregati on behaviors of W and Cr. As was presented, kB indicated a decrease in segreg ation due to 1 at% Ta being substituted for 1 at% Al, but indicated that segregation increased slightly for this same change in alloy chemistry. With the increase in Ta content, it would be expected to observe an increase in the se gregation in Ta (Ta is a dense element, and has a BCC lattice), but Ta may cause the Re to become mo re dispersed within the microstructure. It is know that Ta does increase castability, and th is may partially explain this effect. To fully ascertain the effect of the substitution of 1 at% Ta for 1 at% Al, additional testing would be required on alloys that are not present in the all oy matrix (Table 3-1) (i.e. LMSX-1 baseline with the addition of 1 at% Ta). 5.2.11.2. Effect of decreased tantalum and increased aluminum The effects of substituting 1 at% Al for 1 at% Ta on solidification and segregation were examined using LMSX-1 and -13. These two alloys were examined in the as-cast condition to investigate each elements se gregation pattern as a function of alloy composition.

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122 Figures 4-27 and 4-28 contain the kB graphs for substituting 1 at% Al for 1 at% Ta, and Figure 4-49 contains the graph for substituting 1 at% Al for 1 at% Ta. Both sets of data and graphs show similar trends, a nd in general, as the Al is substituted for Ta, the segregation in the alloy increases. kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores for all except Cr in LMSX13 which was observed to segregate to the interdendritic region. As Al was substituted for Ta, the segregation of Re increased to the greatest degree followed next by W. Co exhib ited a slight increase in segregation when Al was substituted for Ta. The segregation of Cr, as was stated, ch anged direction from the dendrite core to the interdendritic region with this alloy modification. kTa, kAl, and kNi were all less than one, indicating segr egation to the interd endritic region. The segregation of Ta, Al, and Ni all increased (i n this order) when 1 at% Al was substituted for 1 at% Ta. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). The segregation of Re, W, a nd to a lesser degree, Co, all exhibited increased segregation when 1 at% Al was subs tituted for 1 at% Ta. Cr was observed to segregate to the dendrite core in LMSX-1 and then to the interdendritic region in LMSX13. The segregation of Ni and Al also exhibited increasing trends when Al was substituted for Ta. The segregation of Ta exhibited a decrease with the alloy modification, and this can be attributed to the decrease of 1 at% Ta when it was substituted for 1 at% Al. In LMSX-13, Ni was observed to segregate more than Ta; whereas, Ta was observed to segregate more severely in LMSX-1 than Ni.

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123 Both the kB analysis and analysis indicate that when 1 at% Al is substituted for 1 at% Ta, the overall segregation in the alloy increases. This can be observed by Figure 449. A final comparison was done between LMSX-12 and -13 to examine the full effect of substituting Ta for Al and then substituting Al for Ta. Figures 4-29 and 4-30 contain the graphs for the kB analysis, and Figure 4-50 c ontains the graph for the analysis. These graphs are nearly identical to 427, 4-28, and 4-49, and there are no additional trends to be observed. 5.2.12. Tantalum and Aluminum Effects with an Addition of Titanium Ta and Al are not the only formers examined in this investigation. Two model alloys had a small quantity of Ti (another former) added with Ta and Al reduced separately. The model alloys for these experiments were LMSX-14 and -15. The chemistry of LMSX-14 had an decrease of 1 at% Ta (to 1 at%, or a total of 6.0 wt%) and an addition of 1 at% Ti (0.80 wt%). LMSX-15 had Al decreased by 1 at% (to 12 at%) and then the addition of 1 at% Ti (0.80 wt%). These combinations were chosen to again maintain a constant volume fraction of 55%. 5.2.12.1. Effect of decreased tantalum with titanium The effect of substituting 1 at% Ti for 1 at% Ta was examined using LMSX-1 (8.6 wt% Ta, 0 wt% Ti) and -14 (6.0 wt% Ta, 0.8 wt% Ti). Both of these alloys were examined in the as-cast conditi on to investigate each elemen ts segregation pattern as a function of the alloy chemistry. Figures 4-31 and 4-32 contain the kB graphs when 1 at% Ti was substituted for 1 at% Ta, and Figure 4-51 contains the graph for the same change in alloy chemistry.

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124 Both sets of data and graphs show similar trends, and in general, as Ti is substituted for Ta, the elemental segregation in the alloy increased slightly. kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores. The degree of segregation behavior of Re increased when Ti was substituted for Ta in this alloy chemistry. W exhibited the largest increase in segregation when 1 at% Ti was substituted for 1 at% Ta The segregation of Cr increased more significantly than did the segreg ation for Re when substituti ng 1 at% Ti for 1 at% Ta. kTi, kTa, kAl, and kNi were all less than one, indicating segregation to the interdendritic region. The segregation behavi or of Ta and Al increased by similar amounts as Ti was substituted for Ta in this change in alloy chemistry. However, the segregation of Ni decreased with the substitution of 1 at% Ti fo r 1 at% Ti. Ti itself was segregated more than Ta, Al, or Ni when it wa s added as a substitute for Ta. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). The segregation behavior of Re exhibited a decrease in magnitude when 1 at% Ti was substituted for 1 at% Ta. W exhibited an increase in segregation for the substitution of 1 at% Ti for 1 at% Ta. Co exhibited a slight in crease in segregation, and Cr exhibited a slight decr ease in segregation when 1 at% Ti was substituted for 1 at% Ta. The degree of segregation of Ni and Al were observed to increase, with Ni segregating more severely than Al and Ni e xhibited a greater increase in magnitude with the substitution of Ti for Ta. Ta exhibite d a decrease in segregation when Ti was substituted for Ta. Ti was the least segregated element of the formers. The overall segregation increases according to kB graphs, but this trend not immediately observed in the graph. The overall segregation based on was

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125 determined mathematically, and agreed with the kB analysis in that when 1 at% Ti was substituted for 1 at% Ta segregation increase d. However, the increase shown by k could be attributed to error in the analysis ( i1 = 150, and i14 = 153). A difference in this kB and analyses was noted with the se gregation behavior of Ti: the kB indicated that Ti it was the most se verely segregated of the formers, and indicated Ti was the least segregated. This difference is being at tributed to the high scatter when determining k, and the argument brought forth in the example in this chapter. 5.2.12.2. Effect of decreased aluminum with titanium The effect of substituting 1 at% Ti for 1 at% Al on solidification and segregation was examined using LMSX-1 (8.6 wt% Ta, 0 wt % Ti) and -15 (5.1 wt% Al, 0.8 wt% Ti). Both of these alloys were examined in the as-cast condition to inve stigate each elements segregation pattern as a func tion of the alloy chemistry. Figures 4-33 and 4-34 contain the kB graphs when 1 at% Ti was substituted for 1 at% Al, and Figure 4-52 contains the graph for the same change in alloy chemistry. Both sets of data and graphs show differe nt trends when Ti was substituted for Al. kRe, kW, kCo, and kCr were all greater than one, indicating segregation to the dendrite cores. The degree of segregation beha vior of Re increased severely when Ti was substituted for Al in this alloy chemistry. W exhibited an increase in segregation when 1 at% Ti was substituted for 1 at% Ta. The degree of segregation of Cr and Co both increased. Co was observed to segregate mo re than Cr, but the segregation of Cr increased more than the segregation for Co when substituting Ti for Al. kTi, kTa, kAl, and kNi were all less than one, indicating segreg ation to the interdendritic region. The segregation behavior of Ta a nd Al increased by similar amounts as Ti was substituted for

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126 Ta in this change in alloy chemistry. Howeve r, the segregation of Ni decreased slightly when this substitution was done. Ti itself was se gregated more than Ta, Al, or Ni when it was added as a substitute for Al. The curvature, values for these elements follow the same trends as kB (i.e. kB < 1.00, and < 0). The segregation behavior of Re was observed to decrease slightly due to the substitution of 1 at% Ti for 1 at% Al. The segregation behavi ors for W, Co, and Cr all increased by similar amounts (W was the mo st segregated of these three, followed by Co and then Cr) when Ti was substituted for Al Al and Ni exhibite d slight increases in their respective degrees of segregation when 1 at% Ti was substituted for 1 at% Al. Ta exhibited a decrease in segregation wh en substituting 1 at% Ti for 1 at% Al. The overall segregati on trends differ for kB and kB indicated an increase in segregation when 1 at% Ti for 1 at% Al, while indicated that the overall segregation decreases slightly. A difference in the analyses for kB and was observed in the segregation behavior of Ti: the kB indicated Ti was the most severely segregated of the formers, and indicated that Ti was the least segr egated. This difference is from the method and data that is used to calc ulate k. The value used for the xdendrite core was 1.42 and the xinterdentic region was 0.42, therefore kTi was 0.372. A final comparison was done between LMSX-14 and -15 to examine the full effect of substituting Ti for Ta and Al. Figures 4-35 and 4-36 contain the kB graphs, and Figure 4-53 contains the graph. The overall segregation follows very closely to that shown in Figure 4-52. The degree of segrega tion of Re was observed to increase more severely when 1 at% Al was substituted with 1 at% Ta with 1 at% Ti. W and Co both exhibited increases in segregation when Al was substituted for Ta with Ti, and the

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127 segregation of Cr was observed to decrease. The segregatio n behaviors of the elements segregating to the interdendritic (Ni, Al, Ta and Ti), all exhibited increased degrees of segregation with the modificati on to alloy chemistry. Ti was the most segregated of these elements. There were few similarities between kB and trends when 1 at% Al was substituted with 1 at% Ta and a constant level of 1 at% Ti was maintained in the alloy. Re, Co, and Cr exhibited increased segregation as 1 at% Al was substituted with 1 at% Ta with 1 at% Ti. W exhibited a decreasing se gregation due to this change in alloy composition. The segregation of Ti increased slightly and Al segregated slightly less when Al was substituted for Ta. Finally the segregation of Ta was observed to increase the same amount that the segregation of Ni was observed to decrease. Overall, when 1 at% Al was substituted with 1 at% Ta with 1 at% Ti maintained in the alloy, kB indicates an increase in segregati on. The overall effect as indicated by had to be determined mathematically ( i14 = 153, and i15 = 158), which only indicated a slight in crease in segregation. However th e difference calculated may be within experimental error. 5.3. Scheil Analysis To check the validity of this technique of data analysis, data was collected for LMSX-3 in the method described by M.N. Gungor36, using 225 data points.11,38 Data was also collected for CMSX-4 using the techniqu es described in this study and compared to similar graphs found in literature to exam ine the general accuracy of the technique.

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128 5.3.1. Analysis of LMSX-3 The Full analysis was done on LMSX-3 and graphs were then plotted showing the liquid to solid segregation curve that is common to the Gungor method. The data collected from the Short analysis (the technique used in this investigation) was added to these curves and then compared. The curves were only examined for general shape, and no Scheil regression work was done. The curves generated by the Full and Shor t analyses were similar to each another (Figures 5-4, 5-5, and Appendix D). The goa l of this was to see if the shape of the curves were similar for both analyses (Full and Short). Both curves did have similar shapes from both analyses. The similar shapes of the two curves were used to verify that the data collected by the Short analysis was indeed generally accurate when compared to that of the Full analysis. 5.3.2. Analysis of CMSX-4 The LMSX models have little published on their properties and characteristics. Therefore, to evaluate the an alysis technique used in this study, a specimen of as-cast CMSX-4, and then Scheil curves were deve loped and compared to similar curves in literature (Figures 5-6 through 513). In the graphs found in th e literature, th e error bars were ignored and only the average poin ts examined for comparison purposes. The curves for Re (Figures 5-6 and 5-7), Ta (Figures 5-8 and 5-9), and W (Figures 5-11 and 5-16) all look similar in shape and slope and were well within acceptable agreement. The curves for Ti (Figures 5-10 and 5-11) have some s light differences, but still show the same general shape. The Ti curve in Figure 5-10 s hows Ti increasing at a uniform rate, whereas in Figure 5-11, Ti is shown to begin from a constant amount and then begin to increase at a non-uniform rate.

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129 With the Scheil curves generated for CMSX -4 by the technique described in this report and the Scheil curves f ound in open literature, there is some degree of correlation between the two methods. Even though the co mmon analysis is statistically unbiased, the technique used in this report, which is statistically biase d, provides the same information in approximately half of the time.

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130 LMSX-3 Cr Scheil Comparison0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.10.20.30.40.50.60.70.80.91 vol%wt% Cr Full Short Figure 5-4: LMSX-3 Scheil curves for Full and Short techniques for Cr. LMSX-3 Al Scheil Analysis0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.10.20.30.40.50.60.70.80.91 vol%wt% Al Full Short Figure 5-5: LMSX-3 Scheil curves for Full and Short techniques for Al.

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131 Figures 5-6 and 5-7: Scheil curves for Re from CMSX-4. Figure 5-6 was done using the techniques described in this study, and Figure 5-7 was from literature.43 Figures 5-8 and 5-9: Scheil curves for Ta from CMSX-4. Figure 5-8 was done using the techniques described in this study, and Figure 5-9 was from literature.43 Scheil Analysis for Re in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Re Re Scheil Analysis for Ta in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Ta Ta

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132 Figures 5-10 and 5-11: Scheil curves for Ti from CMSX-4. Figure 5-10 was done using the techniques described in this study, and Figure 5-11 was from literature.43 Figure 5-12 and 5-13: Scheil curves for W from CMSX-4. Figure 5-12was done using the techniques described in this study, and Figure 5-13 was from literature.43 Scheil Analysis for Ti in CMSX-40.00 0.50 1.00 1.50 2.00 2.50 3.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Ti Ti Scheil Analysis for W in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% W W

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133 CHAPTER 6 CONCLUSIONS The purpose of this study was to improve upon the understanding of how differential elemental additions affect the segregation of elements in superalloys. A new technique was developed to determine the individual elem ental segregations; instead of random points from the dendrite core and inte rdendritic region, a line scan fro m dendrite core to dendrite core through the interdendritic region was used. The partitioning coefficient, k, was determined using this new technique (kB in this study), and compar ed to a k value done using a more tradit ional technique (kA in this study, done by F. Fela). A k < 1.00 indicated segregation to the in terdendritic region, and a k > 1.00 indicated segregation to the dendrite core. The k values determine by this new technique compared very closely to that of the prior work. The only exceptions ca me from elements that showed very little segregation preference between the dendrite core and the interdendritic region. Scheil curves were also developed to compar e the shape and slope of the curves from the new (Short analysis) technique and compared to a standard (Full analysis) technique. The shapes and slopes of both curves were very similar and agreed wi th one another. An advantage of the new (Short analysis) is its ti me requirement. The scans for LMSX-3 were done in 4.5 hrs using the new (Short analysis ), and 12.5 hrs using the standard (Full analysis). The Short analysis, although st atistically skewed, directly indicates the composition gradient between dendrite cores. Wh ereas the Full analysis looses this direct indication of the composition gradient at th e cost of being stat istically unskewed. In

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134 addition, the Scheil curves for CMSX-4 were developed using the new (Short analysis) technique and compared favorably with the literature. Having shown that kB is equivalent to kA, and the Scheil curves for the data were similar, the study could progress further. k does not give a clear idea of the degree of segregation due to the way it is calculated. The degree of segregat ion was determined by calculating the curvature, from a trendline from the line scan data. A > 0.00 indicated segregation to the de ndrite core, and a < 0.00 indicated segregati on to the interdendritic region. Since kB agreed with kA and the Scheil curves, the data collected is valid. With the data collection valid, and the part itioning based on this data al so verified, further analyses done with the data that provide similar results are also valid. This further analysis was done using The effects of elemental segregation for th irteen trends were evaluated based on the The complete results of the effects of elemental segregation are listed in Table 6-1. The overall effects of the changes in alloy chem istry/composition are listed as follows: Increasing the Co content caused segregation to decrease slightly with the increased Co from 4 wt% (4 at%) content of 8 wt% (8 at%), and a slightly greater decrease as the Co content was increased to 12.2 wt% (13 at%) Increasing the Cr content caused the overall segregation within th e alloy to decrease slightly as Cr content was increased from 2.1 wt% (4 at%) to 6.15 wt% (6 at%). Increasing the Re content caused segregation to increase, with a large initial increase when 1 at% Re was added, and a slight furt her increase with the addition of a second 1 at% Re. When 3 at% Re was added th ere was a very large increase in the segregation within the alloy. Increasing the W content caused segregati on to increase as wt% W was increased from 5.85 wt% (2 at%) to 8.6 wt% (3 at%).

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135 Increasing the W content with an additi on of Mo caused segr egation to increase slightly due to the addition of 1.6 wt% (1 at%) Mo and W content increased form 3.1 wt% (1 at%) to 5.85 wt% (2 at%). Increasing the Mo content caused segregation within the alloy to decrease due to the addition of 1.6 wt% (1 at%) Mo. Increasing the Ru content caused no initia l change in segrega tion when 1.6 wt% (1 at%) Ru was added. However, the additi on of a second 1.6 wt% (1 at%) Ru, for a total of 3.2 wt% (2 at%), cause d a large increase in the overall segreg ation within the alloy. Increasing the Pd content was increased fr om 0 wt% to 1.7 wt% (1 at%), there was an overall increase in the elemental segrega tion within the alloy. Substituting equal amounts of Mo (1 at% Mo) for W (1 at% W) caused the overall segregation decrease. Substituting equal amounts of Ta (1 at% Ta) fo r Al (1 at%) caused very little change in the overall elemental segregation within the alloy as Ta was substituted for Al. However, the segregation di d decrease very slightly. Substituting equal amounts of Al (1 at%) for Ta (1 at%) caused an increase in the elemental segregation as Al was substituted for Ta. Substituting equal amounts of Ta (1 at%) fo r an addition of Ti (1 at%) caused segregation not to change. Substituting equal amounts of Al (1 at%) fo r an addition of Ti (1 at%) caused the overall segregation to decrease slightly. The i also provides a ready indication to the segregation between different alloys. LMSX-9 indicated the lowest degree of segregation and LMSX-11 the greatest degree of segregation (Table 5-1). This ma y help narrow down the search for new alloy compositions, and decrease cost and time in their development, as well as give insight as to how some alloys were developed.

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136 Table 6-1: Elemental segregation effects for each combination of alloy compared. indicates an increase in segregation, indicates a decrease in segregation, and indicates no change in segr egation. Number of arrows is indicative of degree of segregation. AlloysNi CrCoMoWRe Ta AlTiRu wt% Co 4 wt%-8 wt% 1,2 8 wt%-12.2 wt% 2,3 wt% Cr 2.1 wt%-4.1 wt% 5,1 4.1 wt%-6.15 wt% 1,4 wt% Re 0 wt%-2.95 wt% 9,10 2.95 wt%-5.9 wt% 10,1 5.9 wt%-8.7 wt% 1,11 wt% W 5.85 wt%-8.6 wt% 1,6 wt% W +Mo 3.1 wt%-5.85 wt% 7,8 wt% Mo 0 wt%-1.6 wt% 1,8 wt% Ru 0 wt%-1.6 wt% 1,16 1.6 wt%3.2 wt% 16,17 wt% Pd 0 wt%1.7 wt% 1,18 Mo substitution for W + 1 at% Mo, 1 at% W 3.1 wt% W, 1.6 wt% Mo 1,7 5.85 wt% W, 1.6 wt% Mo 6,8

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137 Table 6-1 (cont.): Elemental segregation eff ects for each combination of alloy compared. indicates an increase in segregation, indicates a decrease in segregation, and indicates no change in segr egation. Number of arrows is indicative of degree of segregation. AlloysNiCrCoMoWRe Ta Al Ti Ru Ta substitution for Al + 1 at% Ta, -1 at% Al 11.2 wt% Ta, 5 wt% Al 1,12 Al substitution for Ta + 1 at% Al, -1 at% Ta 6 wt% Ta, 6.15 wt% Al 1,13 1 at% Ta v at% Al 12,13 Ti substitution for Ta + 1 at% Ti, -1 at% Ta 0.8 wt% Ti, 6 wt% Ta 1,14 Ti substitution for Al + 1 at% Ti, -1 at% Al 0.8 wt% Ti, 5.1 wt% Al 1,15 +1 at% Ti, 1 at% (Ta, Al) 14,15

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138 CHAPTER 7 FUTURE WORK This paper has required a tremendous amount of data to be generated. This chapter serves to provide for possible future analyses and experiments to develop an even better understanding of segregation and partitio ning phenomena due to various alloying additions. 7.1. Solidification Front Curves from EMPA All the work in this study was done using normalized weight percents and normalized PDAS, but all the data could be recalculated in three different ways: Normalize Weight Percent and PDAS Atomic Percent and Normalized PDAS Atomic Percent and PDAS The last combination (atomic percent and PDAS) is composition per distance in the cast alloy. The derivative of this is x C and the second derivative is 2 2 x C The use of x C could provide insight into the diffusion gr adients and constants to develop a better understanding of diffusion. 2 2 x C is part of Ficks Second Law, 2 2 x C D t CB B This would become B B BD t C

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139 7.2. Other Elemental Interaction It has been widely speculat ed about many of the elemen tal interactions that are occurring in superalloys. Most analyses onl y vary one elemental composition at a time, and then base more universal results on this narrow change. Expanding the test matrix to cover secondary and tertiary interactions would enhance understanding. The difficultly in expanding the test matrix is cost to manuf acture the alloys. Based on the work in this paper, the following systems are recommende d for examination into understanding the segregation using only solid solution st rengtheners. Table 7-1 gives the recommendations in approximate wt%, and Ta ble 7-1 gives the recommended alloying in at%. Table 7-1 Recommended alloying vari ations to investigate in wt%. Weight Percent (target) Ni Cr Co Mo W Ta Re Al Ti Hf Ru Pd EXSX-1 60.7 4.3 12.6 0.0 6.0 8.9 0.0 5.8 0.0 0.1 1.7 0.0 EXSX-2 59.3 4.2 12.5 0.0 6.0 8.8 0.0 5.7 0.0 0.1 3.3 0.0 EXSX-3 58.5 4.2 12.3 0.0 5.9 8.7 3.0 5.6 0.0 0.1 1.6 0.0 EXSX-4 57.1 4.2 12.2 0.0 5.9 8.7 3.0 5.6 0.0 0.1 3.2 0.0 EXSX-5 64.8 4.1 3.7 1.5 5.8 8.6 5.9 5.5 0.0 0.1 0.0 0.0 EXSX-6 61.1 4.1 7.4 1.5 5.8 8.6 5.9 5.5 0.0 0.1 0.0 0.0 EXSX-7 57.4 4.1 11.2 1.5 5.8 8.6 5.9 5.5 0.0 0.1 0.0 0.0 EXSX-8 56.1 4.1 11.1 1.5 5.8 8.5 5.8 5.5 0.0 0.1 1.6 0.0 EXSX-9 59.7 4.1 7.4 1.5 5.8 8.5 5.8 5.5 0.0 0.1 1.6 0.0 EXSX-10 63.4 4.1 3.7 1.5 5.8 8.5 5.8 5.5 0.0 0.1 1.6 0.0 EXSX-11 61.0 4.1 7.4 0.0 5.8 8.6 5.9 5.5 0.0 0.1 1.6 0.0 EXSX-12 64.7 4.1 3.7 0.0 5.8 8.6 5.9 5.5 0.0 0.1 1.6 0.0

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140 Table 7-2: Recommended alloyi ng variations based on at%. Atomic Percent (target) Ni Cr Co Mo W Ta Re Al Ti Hf Ru Pd EXSX-1 63.0 5.0 13.00.0 2.03.0 0.013.00.00.0 1.0 0.0 EXSX-2 62.0 5.0 13.00.0 2.03.0 0.013.00.00.0 2.0 0.0 EXSX-3 62.0 5.0 13.00.0 2.03.0 1.013.00.00.0 1.0 0.0 EXSX-4 61.0 5.0 13.00.0 2.03.0 1.013.00.00.0 2.0 0.0 EXSX-5 70.0 5.0 4.0 1.0 2.03.02.013.00.00.0 0.0 0.0 EXSX-6 66.0 5.0 8.0 1.0 2.03.02.013.00.00.0 0.0 0.0 EXSX-7 62.0 5.0 12.0 1.0 2.03.02.013.00.00.0 0.0 0.0 EXSX-8 61.0 5.0 12.0 1.0 2.03.02.013.00.00.0 1.0 0.0 EXSX-9 65.0 5.0 8.0 1.0 2.03.02.013.00.00.0 1.0 0.0 EXSX-10 69.0 5.0 4.0 1.0 2.03.02.013.00.00.0 1.0 0.0 EXSX-11 66.0 5.0 8.0 0.0 2.03.02.013.00.00.0 1.0 0.0 EXSX-12 70.0 5.0 4.0 0.0 2.03.02.013.00.00.0 1.0 0.0

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141 APPENDIX A SAMPLE BACKSCATTERED ELECTRON IMAGES This appendix contains a selection of the back scattered electron images that were used to calculate the primary dendrite arm spacing. Two images for each alloy are shown to present a representative sample of the micr ostructure. All images were taken at 100x, and resized for placement in this appendix.

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142 Figure A-1: BSE image of LMSX-1 at 100x. Figure A-2: BSE image of LMSX-1 at 100x.

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143 Figure A-3: BSE image of LMSX-2 at 100x. Figure A-4: BSE image of LMSX-2 at 100x.

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144 Figure A-5: BSE image of LMSX-3 at 100x. Figure A-6: BSE image of LMSX-3 at 100x.

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145 Figure A-7: BSE image of LMSX-4 at 100x. Figure A-8: BSE image of LMSX-4 at 100x.

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146 Figure A-9: BSE image of LMSX-5 at 100x. Figure A-10: BSE image of LMSX-5 at 100x.

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147 Figure A-11: BSE image of LMSX-6 at 100x. Figure A-12: BSE image of LMSX-6 at 100x.

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148 Figure A-13: BSE image of LMSX-7 at 100x. Figure A-14: BSE image of LMSX-7 at 100x.

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149 Figure A-15: BSE image of LMSX-8 at 100x. Figure A-16: BSE image of LMSX-8 at 100x.

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150 Figure A-17: BSE image of LMSX-9 at 100x. Figure A-18: BSE image of LMSX-9 at 100x.

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151 Figure A-19: BSE image of LMSX-10 at 100x. Figure A-20: BSE image of LMSX-10 at 100x.

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152 Figure A-21: BSE image of LMSX-11 at 100x. Figure A-22: BSE image of LMSX-11 at 100x.

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153 Figure A-23: BSE image of LMSX-12 at 100x Figure A-24: BSE image of LMSX-12 at 100x.

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154 Figure A-25: BSE image of LMSX-13 at 100x. Figure A-26: BSE image of LMSX-13 at 100x.

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155 Figure A-27: BSE image of LMSX-14 at 100x. Figure A-28: BSE image of LMSX-14 at 100x.

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156 Figure A-29: BSE image of LMSX-15 at 100x. Figure A-30: BSE image of LMSX-15 at 100x.

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157 Figure A-31: BSE image of LMSX-16 at 100x. Figure A-32: BSE image of LMSX-16 at 100x.

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158 Figure A-33: BSE image of LMSX-17 at 100x. Figure A-34: BSE image of LMSX-17 at 100x.

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159 Figure A-35: BSE image of LMSX-18 at 100x. Figure A-36: BSE image of LMSX-18 at 100x.

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160 APPENDIX B ELECTRON MICROPROBE ANALYSIS SCHEDULES AND SUMMARY OF PROCEDURE USED This appendix contains the schedules used to measure the EMPA data, and a summary of the procedure used in this study fo r ready examination and instruction

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161 Basic Schedule: This was used for all scans other than those specified below. The elements scanned for were based on those f ound in the alloy. See Table 1 for complete elemental composition of all alloys. SETUP SCH [schedule name] PKCNT NI CR CO W RE TA AL HF [the elements particular to this scan] RUN PRZ END Modified Schedule A: Due to the age of the equipment, some of the trace elements were difficult to detect. To detect these trace elem ents, another step was added to the schedule. For alloys LMSX-7 and -8, a step was adde d to measure Mo. For alloys LMSX-14 and15 a similar step was added to measure Ti. For LMSX-16, a step was added to measure the Ru in the alloy. SETUP SCH [schedule name] PKCNT NI CR CO W RE TA AL HF [the elements particular to this scan] MEAS [element specified from above. (i.e. Mo or Ti)] RUN PRZ END Modified Schedule B: Done for the same r eason as the modified schedule A, but only used to measure the compositions in CMSX4. Hf was omitted to shorten scan time. SETUP SCH [schedule name] PKCNT NI CR CO MO W RE TA AL TI MEAS MO MEAS TI RUN PRZ END

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162 Procedure for calculation of segregation behavior 1.) Perform a line scan from dendrite co re to dendrite core through the interdendritic region while trying to a void crossing through any secondary or tertiary dendrite arms 2.) Repeat scans as necessary to generate satisfactory average values. Three were line scans were used in this study 3.) Tabulated data and calculate the averag e value for each element per point of the line scan. 4.) Plot the average values of the elements and fit a second orde r trendline to the data set. 5.) Determine the equation for the trendline 6.) Calculate the second derivative of the trendline equa tion. This is 7.) Repeat for all elements being examined and for all alloys being examined.

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163 APPENDIX C AVERAGE ELECTRON MICROPROBE ANALYSES RESULTS This appendix contains the average results for the EMPA scans done on the eighteen model alloys in both atomic pe rcent and normalized weight percent.

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164Table C-1: Average EMPA data for LMSX-1 Atomic percent (at%) Normalize Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 62.03 4.86 14.79 2.42 3.81 1.74 10.37 0.00 55.89 3.88 13.38 6.84 10.87 4.84 4.30 0.00 61.91 5.19 14.51 2.46 3.74 1.76 10.41 0.00 55.84 4.15 13.14 6.97 10.70 4.89 4.32 0.00 63.24 4.65 13.63 2.17 2.80 2.21 11.29 0.00 58.18 3.79 12.59 6.24 8.15 6.28 4.78 0.00 62.85 5.46 14.33 1.86 2.27 2.34 10.88 0.00 58.57 4.50 13.40 5.43 6.70 6.74 4.57 0.00 64.11 4.70 12.68 1.58 1.43 3.23 12.28 0.00 60.43 3.92 11.98 4.66 4.29 9.40 5.32 0.00 64.41 4.29 11.93 1.46 1.15 3.68 13.09 0.00 60.91 3.59 11.33 4.31 3.44 10.72 5.69 0.00 64.84 4.01 11.87 1.48 1.01 3.73 13.07 0.00 61.37 3.36 11.28 4.38 3.04 10.89 5.68 0.00 64.27 4.40 12.17 1.45 1.26 3.49 12.96 0.00 60.83 3.69 11.56 4.29 3.79 10.20 5.64 0.00 63.88 4.66 12.54 1.54 1.31 3.35 12.73 0.00 60.42 3.90 11.90 4.56 3.93 9.75 5.53 0.00 63.93 4.62 12.07 1.52 1.26 3.54 13.06 0.00 60.41 3.87 11.45 4.51 3.79 10.30 5.67 0.00 64.27 4.41 12.22 1.40 1.04 3.73 12.92 0.00 60.88 3.70 11.61 4.16 3.12 10.90 5.62 0.00 64.22 4.27 11.72 1.34 0.98 3.96 13.50 0.00 60.89 3.59 11.12 3.97 2.94 11.57 5.88 0.00 64.70 4.00 11.56 1.40 0.98 3.91 13.44 0.00 61.29 3.36 10.99 4.15 2.93 11.44 5.85 0.00 64.12 4.01 11.69 1.41 0.92 3.89 13.96 0.00 60.97 3.38 11.15 4.21 2.78 11.40 6.10 0.00 64.33 4.19 11.95 1.39 1.06 3.84 13.26 0.00 60.89 3.51 11.35 4.11 3.17 11.20 5.77 0.00 64.17 4.31 12.00 1.46 1.07 3.68 13.31 0.00 60.85 3.62 11.42 4.33 3.21 10.77 5.80 0.00 63.43 4.94 12.74 1.66 1.66 3.15 12.41 0.00 59.57 4.10 12.00 4.89 4.94 9.13 5.36 0.00 63.73 4.65 12.40 1.58 1.44 3.43 12.77 0.00 60.00 3.87 11.70 4.64 4.28 9.98 5.53 0.00 63.47 4.58 12.66 1.74 1.72 3.37 12.46 0.00 59.19 3.77 11.83 5.08 5.07 9.71 5.35 0.00 62.69 5.19 13.67 1.79 2.14 2.81 11.72 0.00 58.37 4.28 12.78 5.22 6.29 8.05 5.02 0.00 63.69 4.51 12.53 1.59 1.53 3.35 12.80 0.00 59.91 3.76 11.82 4.68 4.57 9.73 5.54 0.00 63.20 5.29 13.11 1.49 1.59 3.24 12.08 0.00 59.48 4.41 12.38 4.38 4.73 9.39 5.23 0.00 63.79 4.48 12.55 1.57 1.41 3.50 12.70 0.00 59.97 3.73 11.83 4.62 4.19 10.16 5.49 0.00 64.66 4.06 11.96 1.45 1.15 3.64 13.07 0.00 61.19 3.40 11.35 4.29 3.44 10.64 5.69 0.00 64.56 4.13 12.33 1.52 1.24 3.42 12.69 0.00 61.13 3.46 11.70 4.51 3.71 9.98 5.52 0.00 63.99 4.52 12.96 1.73 1.79 2.82 12.19 0.00 60.15 3.76 12.23 5.09 5.32 8.18 5.27 0.00 63.67 4.79 13.27 1.86 2.12 2.52 11.78 0.00 59.55 3.96 12.44 5.44 6.28 7.26 5.06 0.00 62.78 4.96 14.06 2.17 3.10 2.08 10.86 0.00 57.46 4.02 12.91 6.21 8.97 5.87 4.57 0.00 62.40 4.98 14.23 2.38 3.71 1.83 10.47 0.00 56.34 3.98 12.89 6.72 10.63 5.09 4.34 0.00 Average 62.02 5.04 14.58 2.39 3.86 1.79 10.33 0.00 55.83 4.01 13.17 6.74 11.01 4.96 4.28 0.00

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165Table C-2: Average EMPA data for LMSX-2 Atomic percent (at%) Normalize Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 65.82 5.35 9.98 2.44 3.91 1.69 10.81 0.00 59.41 4.27 9.04 6.90 11.19 4.70 4.49 0.00 65.97 5.55 10.09 2.41 4.05 1.62 10.32 0.00 59.37 4.43 9.11 6.80 11.54 4.49 4.27 0.00 66.20 5.48 9.79 2.21 3.18 1.93 11.22 0.00 60.76 4.45 9.02 6.34 9.23 5.46 4.73 0.00 67.25 4.92 8.61 1.79 2.04 2.68 12.70 0.00 63.20 4.10 8.12 5.25 6.06 7.78 5.49 0.00 67.65 4.41 8.14 1.47 1.40 3.45 13.49 0.00 64.07 3.70 7.74 4.35 4.21 10.06 5.87 0.00 66.48 5.62 8.90 1.53 1.91 2.98 12.58 0.00 62.62 4.68 8.41 4.50 5.69 8.65 5.45 0.00 67.63 4.18 7.61 1.41 1.03 3.77 14.37 0.00 64.51 3.51 7.27 4.20 3.09 11.11 6.30 0.00 67.49 4.49 7.93 1.49 1.35 3.45 13.80 0.00 64.06 3.78 7.55 4.45 4.06 10.09 6.02 0.00 66.61 5.37 8.45 1.56 1.74 3.07 13.19 0.00 62.97 4.49 8.02 4.61 5.22 8.96 5.73 0.00 67.29 4.82 7.78 1.51 1.42 3.35 13.82 0.00 63.91 4.05 7.42 4.48 4.28 9.83 6.03 0.00 66.37 5.47 8.43 1.48 1.69 3.26 13.30 0.00 62.72 4.57 7.99 4.37 5.07 9.51 5.78 0.00 68.41 3.42 7.10 1.20 0.66 4.29 14.91 0.00 65.47 2.90 6.82 3.59 1.99 12.67 6.54 0.00 67.78 3.74 7.28 1.33 0.89 3.93 15.05 0.00 64.91 3.17 7.00 3.99 2.71 11.60 6.63 0.00 67.43 4.31 7.40 1.42 1.09 3.69 14.66 0.00 64.41 3.65 7.10 4.24 3.28 10.88 6.44 0.00 67.59 4.09 7.54 1.50 1.18 3.52 14.56 0.00 64.51 3.45 7.22 4.48 3.57 10.38 6.39 0.00 64.05 7.75 10.05 1.85 2.86 2.31 11.12 0.00 59.30 6.33 9.31 5.34 8.33 6.65 4.74 0.00 67.53 4.26 8.06 1.45 1.35 3.48 13.70 0.18 63.85 3.56 7.64 4.29 4.04 10.16 5.96 0.51 67.88 4.06 7.47 1.57 1.26 3.47 14.31 0.00 64.58 3.40 7.12 4.67 3.77 10.19 6.26 0.00 66.72 5.09 8.58 1.63 1.71 3.16 13.11 0.00 62.89 4.25 8.11 4.79 5.11 9.17 5.68 0.00 66.69 5.13 8.27 1.44 1.42 3.55 13.49 0.00 63.13 4.28 7.84 4.26 4.25 10.36 5.87 0.00 67.18 4.75 7.79 1.27 1.17 3.83 14.01 0.00 63.91 4.00 7.43 3.78 3.52 11.23 6.13 0.00 66.28 5.84 8.37 1.34 1.37 3.50 13.31 0.00 62.97 4.90 7.98 3.97 4.12 10.24 5.81 0.00 67.64 4.20 7.43 1.35 1.12 3.79 14.47 0.00 64.47 3.54 7.11 4.02 3.38 11.15 6.34 0.00 67.88 3.87 7.48 1.35 0.98 3.93 14.52 0.00 64.70 3.26 7.16 4.02 2.96 11.56 6.36 0.00 67.24 4.51 8.21 1.27 1.35 3.63 13.79 0.00 63.89 3.78 7.82 3.79 4.05 10.64 6.03 0.00 66.33 5.93 9.17 1.37 1.96 3.01 12.22 0.00 62.46 4.93 8.65 4.05 5.84 8.77 5.30 0.00 66.83 4.85 8.70 1.71 1.94 2.99 12.98 0.00 62.74 4.02 8.19 5.01 5.77 8.66 5.60 0.00 65.90 5.37 9.30 2.18 3.23 2.10 11.92 0.00 60.46 4.37 8.57 6.27 9.39 5.93 5.02 0.00 66.25 4.91 9.58 2.39 3.78 1.86 11.25 0.00 59.91 3.93 8.69 6.76 10.85 5.19 4.67 0.00 Average 66.19 5.13 9.53 2.37 3.78 1.80 11.22 0.00 59.96 4.11 8.66 6.73 10.85 5.02 4.67 0.00

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166Table C-3: Average EMPA data for LMSX-3. Atomic percent (at%) Normalize Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 71.86 4.88 4.69 2.35 3.66 1.78 10.78 0.00 65.14 3.91 4.27 6.68 10.53 4.98 4.49 0.00 71.52 5.32 5.01 2.42 3.98 1.61 10.14 0.00 64.38 4.24 4.53 6.81 11.37 4.46 4.19 0.00 71.45 5.01 4.72 2.37 3.48 1.87 11.10 0.00 64.99 4.04 4.31 6.73 10.04 5.25 4.64 0.00 71.72 5.60 4.80 2.07 2.91 2.01 10.87 0.00 66.14 4.57 4.44 5.98 8.51 5.74 4.61 0.00 72.20 5.06 4.19 1.63 1.73 2.83 12.37 0.00 68.21 4.23 3.97 4.81 5.18 8.23 5.37 0.00 72.62 3.72 3.60 1.32 1.04 3.73 13.98 0.00 69.28 3.12 3.43 3.91 3.08 11.03 6.14 0.00 72.52 4.05 3.70 1.48 1.20 3.49 13.55 0.00 68.94 3.39 3.52 4.37 3.57 10.28 5.93 0.00 71.60 4.96 4.20 1.62 1.92 2.90 12.80 0.00 67.44 4.14 3.97 4.76 5.71 8.43 5.55 0.00 71.91 4.57 4.14 1.71 1.86 2.94 12.89 0.00 67.66 3.80 3.90 5.01 5.51 8.54 5.58 0.00 72.17 4.32 3.78 1.68 1.56 3.10 13.40 0.00 68.28 3.62 3.59 4.97 4.68 9.05 5.83 0.00 71.15 5.54 4.50 1.71 2.15 2.70 12.25 0.00 66.72 4.60 4.23 5.00 6.36 7.80 5.28 0.00 71.05 6.33 4.43 1.63 1.94 2.63 12.00 0.00 67.05 5.30 4.19 4.82 5.80 7.64 5.21 0.00 71.25 5.03 4.15 1.45 1.45 3.26 13.41 0.00 67.72 4.23 3.96 4.30 4.36 9.56 5.86 0.00 71.93 4.22 3.67 1.33 1.04 3.71 14.10 0.00 68.70 3.57 3.51 3.96 3.13 10.94 6.19 0.00 72.34 3.83 3.56 1.23 0.73 3.96 14.35 0.00 69.37 3.25 3.42 3.69 2.22 11.71 6.33 0.00 71.99 4.42 3.66 1.19 0.86 3.83 14.04 0.00 69.01 3.74 3.52 3.58 2.62 11.35 6.19 0.00 71.89 4.31 3.80 1.23 0.96 3.66 14.16 0.00 69.00 3.66 3.66 3.70 2.90 10.82 6.25 0.00 71.35 4.97 3.90 1.41 1.32 3.43 13.62 0.00 67.89 4.18 3.72 4.21 3.97 10.05 5.96 0.00 72.60 3.14 3.48 1.19 0.60 4.12 14.87 0.00 69.80 2.67 3.36 3.59 1.82 12.20 6.57 0.00 71.21 5.85 4.51 1.46 1.86 2.86 12.24 0.00 67.27 4.90 4.28 4.33 5.57 8.33 5.32 0.00 72.04 4.27 3.82 1.49 1.27 3.28 13.83 0.00 68.73 3.60 3.65 4.45 3.84 9.67 6.06 0.00 71.76 5.15 4.08 1.54 1.76 2.87 12.84 0.00 68.00 4.31 3.88 4.57 5.25 8.39 5.59 0.00 71.51 5.68 4.46 1.46 1.93 2.72 12.23 0.00 67.65 4.75 4.23 4.33 5.78 7.94 5.33 0.00 71.24 6.24 4.58 1.40 1.80 2.76 11.98 0.00 67.58 5.24 4.35 4.14 5.39 8.07 5.23 0.00 72.54 4.16 3.80 1.26 1.07 3.51 13.66 0.00 69.45 3.52 3.65 3.76 3.23 10.38 6.01 0.00 72.43 4.40 3.75 1.57 1.28 3.12 13.46 0.00 69.09 3.72 3.59 4.68 3.86 9.17 5.90 0.00 72.15 4.82 4.30 1.77 2.19 2.46 12.31 0.00 67.79 4.00 4.05 5.19 6.52 7.13 5.32 0.00 71.64 5.01 4.60 2.20 3.08 1.99 11.49 0.00 65.89 4.08 4.24 6.31 8.97 5.64 4.86 0.00 71.66 5.12 4.83 2.41 3.80 1.64 10.53 0.00 64.83 4.11 4.39 6.83 10.89 4.57 4.38 0.00 Average 71.73 4.88 4.77 2.37 3.76 1.75 10.74 0.00 64.90 3.92 4.33 6.71 10.79 4.89 4.46 0.00

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167Table C-4: Average EMPA data for LMSX-4. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 59.58 7.82 14.65 2.34 3.78 1.52 10.31 0.00 54.19 6.30 13.37 6.67 10.89 4.26 4.31 0.00 59.78 7.82 14.22 2.23 3.35 1.76 10.83 0.00 54.87 6.35 13.10 6.40 9.72 5.00 4.57 0.00 60.22 7.63 13.84 2.08 2.91 1.95 11.36 0.00 55.86 6.27 12.89 6.03 8.53 5.58 4.85 0.00 61.00 6.91 13.17 1.94 2.45 2.45 12.07 0.00 56.90 5.69 12.31 5.65 7.19 7.09 5.18 0.00 61.30 6.84 12.67 1.61 1.80 3.04 12.74 0.00 57.82 5.70 11.98 4.76 5.34 8.87 5.53 0.00 59.87 7.85 13.87 1.84 2.71 2.19 11.67 0.00 55.89 6.48 12.97 5.35 7.96 6.33 5.01 0.00 60.74 7.69 13.02 1.73 2.02 2.48 12.33 0.00 57.44 6.44 12.36 5.11 6.05 7.24 5.36 0.00 61.38 7.09 12.52 1.42 1.31 3.44 12.79 0.05 58.20 5.95 11.91 4.21 3.94 10.06 5.57 0.15 61.62 6.89 12.15 1.48 1.39 3.21 13.26 0.00 58.72 5.82 11.62 4.41 4.19 9.42 5.81 0.00 60.79 7.18 12.90 1.80 2.32 2.62 12.41 0.00 56.95 5.95 12.10 5.25 6.81 7.59 5.35 0.00 60.51 7.32 13.12 1.82 2.04 2.59 12.61 0.00 57.05 6.11 12.40 5.35 6.07 7.55 5.47 0.00 59.96 7.77 13.05 1.84 2.28 2.68 12.43 0.00 56.13 6.42 12.24 5.38 6.70 7.77 5.35 0.00 60.88 7.46 12.37 1.45 1.43 3.29 13.11 0.00 57.91 6.28 11.80 4.31 4.31 9.66 5.73 0.00 62.42 5.77 11.90 1.48 1.21 3.65 13.56 0.00 59.20 4.84 11.32 4.38 3.64 10.70 5.92 0.00 60.47 7.32 12.77 1.66 1.88 3.20 12.69 0.00 56.73 6.07 12.01 4.86 5.56 9.29 5.48 0.00 62.09 6.18 11.71 1.35 1.05 3.80 13.82 0.00 59.16 5.21 11.19 4.03 3.16 11.18 6.05 0.00 60.33 7.74 13.48 1.64 2.01 2.67 12.13 0.00 56.89 6.46 12.75 4.84 5.99 7.80 5.26 0.00 60.12 7.72 13.17 1.68 2.12 2.64 12.56 0.00 56.71 6.45 12.46 4.93 6.31 7.69 5.45 0.00 59.78 8.30 12.89 1.49 1.77 2.95 12.83 0.00 56.77 6.98 12.28 4.43 5.33 8.62 5.60 0.00 61.47 6.87 11.71 1.54 1.20 3.69 13.52 0.00 58.26 5.77 11.14 4.56 3.60 10.78 5.89 0.00 61.44 6.29 12.34 1.76 1.93 3.16 13.08 0.00 57.61 5.20 11.58 5.14 5.63 9.19 5.65 0.00 60.74 6.82 12.82 1.69 1.95 3.13 12.85 0.00 56.97 5.65 12.04 4.94 5.76 9.09 5.54 0.00 61.97 6.20 11.80 1.47 1.19 3.65 13.72 0.00 58.90 5.21 11.25 4.35 3.59 10.69 6.00 0.00 62.88 5.45 11.54 1.37 1.13 3.74 13.89 0.00 59.86 4.58 11.01 4.08 3.38 11.01 6.08 0.00 62.01 6.13 12.13 1.59 1.51 3.36 13.27 0.00 58.60 5.12 11.49 4.69 4.53 9.80 5.77 0.00 60.74 7.48 12.82 1.61 1.86 2.93 12.58 0.00 57.34 6.25 12.13 4.74 5.54 8.54 5.46 0.00 61.87 6.43 12.52 1.71 2.04 2.98 12.45 0.00 57.93 5.30 11.74 5.00 6.00 8.66 5.36 0.00 60.38 7.38 13.63 2.00 2.91 2.17 11.54 0.00 55.91 6.05 12.65 5.77 8.49 6.21 4.92 0.00 60.20 7.66 13.85 2.11 3.06 1.93 11.18 0.00 55.60 6.27 12.84 6.09 8.95 5.51 4.75 0.00 Average 59.53 7.72 14.44 2.29 3.76 1.60 10.66 0.00 54.23 6.23 13.21 6.54 10.86 4.48 4.46 0.00

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168Table C-5: Average EMPA data for LMSX-5. Atomic percent (at%) Normalize Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 65.14 3.15 14.75 1.97 3.12 1.24 10.62 0.00 60.58 2.59 13.77 5.74 9.21 3.56 4.54 0.00 65.33 2.60 14.94 1.99 3.14 1.29 10.71 0.00 60.64 2.14 13.92 5.79 9.25 3.69 4.57 0.00 65.81 3.09 14.14 1.75 2.54 1.52 11.15 0.00 62.06 2.58 13.38 5.15 7.57 4.42 4.84 0.00 66.50 2.48 13.57 1.46 1.89 1.90 12.20 0.00 63.75 2.11 13.04 4.38 5.70 5.64 5.38 0.00 66.29 2.95 13.31 1.52 1.63 1.95 12.35 0.00 63.83 2.51 12.86 4.57 4.96 5.79 5.47 0.00 66.32 2.66 13.51 1.51 1.79 1.92 12.28 0.00 63.64 2.26 13.02 4.53 5.45 5.68 5.42 0.00 65.93 3.04 13.63 1.53 1.73 1.87 12.28 0.00 63.40 2.59 13.15 4.60 5.28 5.55 5.43 0.00 66.56 2.46 13.34 1.42 1.57 2.02 12.62 0.00 64.26 2.10 12.92 4.30 4.81 6.00 5.60 0.00 66.29 3.06 13.48 1.31 1.49 2.00 12.37 0.00 64.24 2.63 13.11 3.98 4.57 5.97 5.51 0.00 67.08 2.50 12.86 1.23 1.16 2.26 12.90 0.00 65.36 2.16 12.58 3.75 3.59 6.78 5.78 0.00 66.66 2.90 12.87 1.10 1.07 2.36 13.04 0.00 65.18 2.52 12.59 3.38 3.33 7.11 5.86 0.00 67.23 2.35 12.52 1.17 0.96 2.51 13.26 0.00 65.66 2.03 12.27 3.56 2.97 7.55 5.95 0.00 66.51 3.00 13.06 1.14 1.12 2.31 12.86 0.00 64.94 2.59 12.80 3.48 3.46 6.96 5.77 0.00 66.78 2.58 12.95 1.25 1.08 2.29 13.07 0.00 65.15 2.23 12.68 3.81 3.36 6.90 5.86 0.00 66.45 3.07 13.14 1.15 1.16 2.23 12.80 0.00 64.88 2.65 12.87 3.54 3.59 6.72 5.75 0.00 66.84 2.43 13.07 1.22 1.20 2.28 12.95 0.00 65.06 2.10 12.77 3.71 3.71 6.86 5.79 0.00 66.20 2.99 13.42 1.18 1.24 2.24 12.73 0.00 64.47 2.58 13.11 3.60 3.81 6.73 5.70 0.00 66.77 2.48 13.05 1.14 1.08 2.31 13.18 0.00 65.31 2.15 12.81 3.47 3.35 6.98 5.93 0.00 66.54 3.08 12.77 1.28 1.17 2.20 12.95 0.00 64.88 2.66 12.51 3.92 3.61 6.61 5.80 0.00 66.59 2.49 13.04 1.37 1.34 2.06 13.13 0.00 64.80 2.14 12.74 4.16 4.12 6.17 5.87 0.00 66.25 2.90 13.29 1.42 1.47 1.98 12.70 0.00 64.20 2.49 12.92 4.30 4.50 5.93 5.66 0.00 66.47 2.57 13.35 1.41 1.53 1.99 12.68 0.00 64.31 2.20 12.96 4.27 4.70 5.93 5.64 0.00 66.65 2.94 13.18 1.37 1.49 1.96 12.41 0.00 64.56 2.52 12.81 4.16 4.57 5.85 5.52 0.00 66.84 2.43 13.24 1.33 1.44 2.09 12.63 0.00 64.73 2.08 12.86 4.05 4.41 6.24 5.62 0.00 66.50 2.91 13.18 1.33 1.35 2.12 12.60 0.00 64.51 2.50 12.82 4.05 4.15 6.35 5.62 0.00 66.78 2.45 13.15 1.43 1.51 1.98 12.69 0.00 64.60 2.10 12.77 4.35 4.62 5.92 5.64 0.00 65.95 2.95 14.06 1.65 2.13 1.60 11.66 0.00 62.88 2.50 13.45 4.93 6.44 4.69 5.11 0.00 65.82 2.59 14.46 1.94 2.89 1.35 10.96 0.00 61.49 2.14 13.56 5.67 8.56 3.87 4.71 0.00 65.32 3.07 14.38 2.02 3.20 1.31 10.70 0.00 60.55 2.52 13.39 5.86 9.40 3.73 4.56 0.00 Average 65.41 2.62 15.05 1.95 3.15 1.25 10.56 0.00 60.75 2.16 14.03 5.68 9.29 3.58 4.51 0.00

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169Table C-6: Average EMPA data for LMSX-6. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 61.92 5.11 14.83 2.74 3.01 1.20 11.19 0.00 57.17 4.17 13.75 7.93 8.82 3.41 4.75 0.00 60.73 5.75 15.19 2.94 3.16 1.21 10.92 0.00 55.72 4.67 13.97 8.44 9.17 3.43 4.60 0.00 61.95 4.80 14.72 2.64 2.73 1.37 11.77 0.00 57.60 3.95 13.74 7.68 8.06 3.94 5.03 0.00 62.20 4.97 14.22 2.57 2.49 1.52 12.03 0.00 58.12 4.10 13.33 7.52 7.36 4.39 5.17 0.00 61.60 5.52 14.43 2.47 2.28 1.59 12.12 0.00 57.95 4.59 13.60 7.25 6.74 4.62 5.25 0.00 62.02 5.46 13.94 2.26 1.82 1.91 12.59 0.00 58.92 4.58 13.26 6.69 5.42 5.62 5.50 0.00 62.01 5.62 13.99 1.94 1.65 2.04 12.76 0.00 59.35 4.77 13.44 5.81 5.00 6.02 5.61 0.00 63.93 4.17 12.40 1.75 1.06 2.45 14.25 0.00 62.10 3.58 12.07 5.30 3.25 7.34 6.37 0.00 63.49 4.47 12.68 1.84 1.25 2.39 13.89 0.00 61.30 3.81 12.27 5.53 3.78 7.13 6.17 0.00 63.91 4.22 12.27 1.75 1.00 2.60 14.23 0.00 61.95 3.61 11.92 5.30 3.06 7.81 6.34 0.00 61.25 6.46 13.85 2.04 1.71 2.01 12.69 0.00 58.53 5.45 13.27 6.09 5.18 5.91 5.57 0.00 61.95 5.66 13.48 2.02 1.59 2.09 13.25 0.00 59.34 4.80 12.96 6.05 4.83 6.17 5.83 0.00 62.01 5.40 13.44 1.83 1.44 2.17 13.70 0.00 59.89 4.61 13.02 5.52 4.40 6.48 6.08 0.00 62.53 5.08 12.99 1.80 1.26 2.52 13.82 0.00 60.28 4.32 12.54 5.40 3.81 7.52 6.13 0.00 63.37 4.35 12.28 1.46 0.92 2.85 14.76 0.00 61.76 3.75 12.01 4.47 2.84 8.46 6.61 0.00 62.49 5.30 12.63 1.58 1.11 2.71 14.17 0.00 60.55 4.54 12.28 4.80 3.41 8.10 6.32 0.00 63.53 4.44 12.06 1.41 0.89 2.97 14.71 0.00 61.85 3.83 11.79 4.29 2.75 8.90 6.58 0.00 62.65 5.25 12.76 1.51 1.16 2.60 14.07 0.00 60.83 4.50 12.42 4.61 3.56 7.79 6.28 0.00 64.40 3.98 11.88 1.42 0.82 2.74 14.76 0.00 63.07 3.45 11.67 4.34 2.54 8.29 6.65 0.00 63.26 4.60 12.40 1.66 1.03 2.48 14.57 0.00 61.68 3.97 12.14 5.07 3.18 7.43 6.53 0.00 62.88 4.89 12.96 1.94 1.51 2.17 13.64 0.00 60.46 4.16 12.49 5.82 4.57 6.46 6.04 0.00 62.30 5.26 13.38 2.02 1.63 1.97 13.45 0.00 59.83 4.47 12.90 6.08 4.97 5.82 5.94 0.00 62.00 5.02 13.71 2.17 1.79 1.90 13.41 0.00 59.26 4.24 13.14 6.47 5.40 5.61 5.90 0.00 62.04 5.39 13.51 2.15 1.74 1.93 13.25 0.00 59.69 4.26 12.92 6.38 5.18 5.73 5.83 0.00 62.07 5.31 13.78 2.23 1.96 1.83 12.81 0.00 58.93 4.46 13.13 6.61 5.89 5.38 5.60 0.00 62.10 5.35 13.94 2.28 2.13 1.70 12.51 0.00 58.75 4.48 13.24 6.77 6.38 4.95 5.44 0.00 62.26 5.09 14.27 2.32 2.32 1.57 12.17 0.00 58.66 4.24 13.49 6.85 6.92 4.56 5.27 0.00 61.42 5.70 14.69 2.66 2.88 1.29 11.36 0.00 56.97 4.67 13.66 7.71 8.44 3.70 4.84 0.00 61.40 5.25 15.10 3.05 3.16 1.18 10.85 0.00 56.12 4.25 13.86 8.71 9.16 3.33 4.56 0.00 Average 60.83 5.75 15.23 2.89 3.12 1.25 10.94 0.00 55.80 4.67 14.02 8.30 9.07 3.53 4.62 0.00

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170Table C-7: Average EMPA data for LMSX-7. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co Mo W Re Ta Al Hf Ni Cr Co Mo W Re Ta Al Hf 63.87 5.01 14.07 1.04 0.97 2.92 1.34 10.69 0.00 60.53 4.20 13.39 1.61 2.88 8.76 3.92 4.70 0.00 63.25 5.44 14.14 0.99 0.97 2.93 1.38 10.89 0.00 59.97 4.57 13.46 1.53 2.88 8.80 4.05 4.75 0.00 63.67 5.13 14.03 1.00 0.92 2.38 1.64 11.23 0.00 60.89 4.35 13.47 1.56 2.75 7.20 4.84 4.93 0.00 64.58 5.07 12.50 1.00 0.77 1.37 2.22 12.49 0.00 62.97 4.37 12.22 1.60 2.33 4.22 6.68 5.60 0.00 65.05 4.58 12.39 0.96 0.77 1.17 2.41 12.67 0.00 63.49 3.95 12.12 1.53 2.36 3.61 7.22 5.69 0.00 64.22 5.48 12.49 1.16 0.73 1.24 2.27 12.41 0.00 62.69 4.73 12.23 1.84 2.24 3.85 6.84 5.57 0.00 64.79 4.79 12.75 1.06 0.73 1.28 2.26 12.34 0.00 63.18 4.12 12.48 1.69 2.22 3.96 6.80 5.53 0.00 64.36 5.20 12.60 1.11 0.71 1.18 2.39 12.47 0.00 62.80 4.50 12.34 1.76 2.17 3.65 7.19 5.58 0.00 64.10 4.84 12.97 1.12 0.73 1.34 2.39 12.51 0.00 62.31 4.17 12.65 1.78 2.21 4.13 7.16 5.59 0.00 63.73 5.40 12.73 1.22 0.76 1.33 2.43 12.39 0.00 61.82 4.63 12.39 1.93 2.30 4.10 7.30 5.52 0.00 64.69 4.39 12.42 0.83 0.71 1.19 2.62 13.15 0.00 63.10 3.79 12.16 1.32 2.17 3.70 7.87 5.90 0.00 64.05 5.32 12.48 1.08 0.69 1.14 2.54 12.70 0.00 62.49 4.59 12.23 1.72 2.11 3.53 7.63 5.70 0.00 64.18 4.92 12.46 1.15 0.69 1.13 2.47 13.00 0.00 62.75 4.26 12.23 1.84 2.12 3.51 7.45 5.84 0.00 64.00 5.32 12.11 1.35 0.72 1.19 2.41 12.90 0.00 62.48 4.60 11.86 2.16 2.21 3.67 7.24 5.79 0.00 64.22 4.83 12.42 1.39 0.83 1.19 2.46 12.67 0.00 62.34 4.15 12.10 2.20 2.51 3.67 7.37 5.65 0.00 63.37 5.88 13.20 1.15 0.67 1.35 2.30 12.08 0.00 61.68 5.07 12.89 1.82 2.04 4.17 6.92 5.40 0.00 64.07 4.99 12.92 1.25 0.69 1.26 2.37 12.45 0.00 62.41 4.29 12.62 1.99 2.09 3.90 7.12 5.57 0.00 63.59 5.57 13.14 1.13 0.65 1.23 2.47 12.23 0.00 61.91 4.80 12.84 1.80 1.97 3.79 7.41 5.47 0.00 63.57 5.45 13.40 1.14 0.77 1.40 2.25 12.02 0.00 61.71 4.69 13.07 1.81 2.32 4.32 6.72 5.36 0.00 64.80 4.69 12.00 0.94 0.83 1.24 2.65 12.86 0.00 62.84 4.02 11.68 1.48 2.51 3.80 7.93 5.73 0.00 64.51 4.57 12.56 1.00 0.78 1.16 2.55 12.87 0.00 62.82 3.93 12.27 1.60 2.37 3.59 7.67 5.76 0.00 63.63 5.51 13.15 1.14 0.70 1.46 2.28 12.13 0.00 61.80 4.74 12.81 1.82 2.13 4.48 6.81 5.41 0.00 64.60 4.57 12.40 1.35 0.80 1.40 2.31 12.59 0.00 62.66 3.92 12.07 2.12 2.42 4.29 6.91 5.61 0.00 63.41 5.88 13.42 1.02 0.77 1.49 1.99 12.03 0.00 61.83 5.07 13.13 1.62 2.37 4.59 5.99 5.39 0.00 64.20 4.98 13.21 0.97 0.84 1.57 2.02 12.21 0.00 62.40 4.28 12.88 1.54 2.57 4.83 6.04 5.45 0.00 63.73 5.51 13.28 1.10 0.83 1.66 1.88 12.02 0.00 61.94 4.74 12.96 1.74 2.50 5.12 5.61 5.37 0.00 64.27 5.03 13.65 1.10 0.79 2.01 1.74 11.42 0.00 62.01 4.30 13.22 1.73 2.38 6.13 5.18 5.06 0.00 63.56 5.63 13.74 1.03 0.90 2.57 1.49 11.08 0.00 60.72 4.76 13.17 1.61 2.70 7.78 4.39 4.86 0.00 63.67 5.01 14.24 1.04 0.99 2.92 1.35 10.77 0.00 60.30 4.20 13.54 1.61 2.94 8.77 3.95 4.69 0.00 Average 63.20 5.63 14.30 0.95 0.91 2.86 1.36 10.77 0.00 60.11 4.74 13.65 1.48 2.70 8.64 3.97 4.72 0.00

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171Table C-8: Average EMPA data for LMSX-8. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co Mo W Re Ta Al Hf Ni Cr Co Mo W Re Ta Al Hf 61.76 5.05 14.68 1.00 1.91 3.09 1.27 11.23 0.00 57.47 4.16 13.71 1.53 5.55 9.14 3.64 4.80 0.00 62.04 5.32 14.35 0.99 1.89 2.96 1.37 11.07 0.00 57.75 4.39 13.41 1.51 5.52 8.75 3.94 4.73 0.00 62.22 5.02 14.15 1.15 1.79 2.64 1.52 11.50 0.00 58.31 4.17 13.31 1.76 5.24 7.86 4.40 4.95 0.00 61.85 5.76 14.08 1.21 1.65 2.15 1.76 11.54 0.00 58.47 4.82 13.35 1.87 4.88 6.43 5.15 5.01 0.00 62.18 5.53 13.78 1.30 1.49 1.81 2.10 11.81 0.00 59.04 4.65 13.13 2.02 4.44 5.44 6.13 5.16 0.00 63.71 4.66 12.31 0.86 1.44 1.32 2.57 13.13 0.00 61.14 3.95 11.83 1.34 4.32 3.99 7.63 5.80 0.00 62.48 5.23 13.54 1.24 1.50 1.73 2.15 12.12 0.00 59.43 4.40 12.92 1.93 4.47 5.23 6.30 5.30 0.00 62.07 5.68 13.45 1.25 1.45 1.68 2.04 12.39 0.00 59.41 4.82 12.92 1.95 4.33 5.11 6.02 5.45 0.00 62.32 5.21 13.47 1.34 1.46 1.52 2.20 12.48 0.00 59.62 4.40 12.93 2.09 4.38 4.62 6.47 5.49 0.00 62.48 5.56 13.35 1.18 1.40 1.48 2.25 12.30 0.00 59.85 4.72 12.84 1.85 4.20 4.48 6.66 5.42 0.00 63.53 4.73 12.95 1.04 1.33 1.22 2.39 12.81 0.00 61.26 4.04 12.54 1.64 4.01 3.74 7.09 5.68 0.00 62.15 5.39 13.33 1.09 1.44 1.54 2.10 12.96 0.00 59.82 4.59 12.87 1.70 4.34 4.69 6.25 5.73 0.00 62.31 5.51 13.48 1.25 1.40 1.72 2.08 12.25 0.00 59.55 4.67 12.93 1.95 4.19 5.21 6.14 5.38 0.00 64.53 4.15 11.64 0.79 1.20 0.85 2.89 13.97 0.00 62.71 3.58 11.33 1.25 3.63 2.60 8.68 6.24 0.00 63.88 3.94 12.18 0.95 1.25 1.13 2.59 14.07 0.00 61.97 3.38 11.84 1.50 3.81 3.47 7.75 6.28 0.00 61.78 5.69 13.41 1.20 1.50 1.62 2.16 12.64 0.00 59.10 4.82 12.97 1.88 4.50 4.90 6.37 5.56 0.00 62.92 5.07 13.02 1.18 1.41 1.36 2.39 12.64 0.00 60.31 4.30 12.53 1.85 4.24 4.14 7.06 5.57 0.00 63.73 4.67 11.87 1.14 1.29 0.95 2.84 13.52 0.00 61.50 3.98 11.49 1.80 3.89 2.90 8.44 6.00 0.00 62.96 4.99 12.98 1.18 1.26 1.28 2.46 12.89 0.00 60.63 4.25 12.52 1.86 3.80 3.92 7.29 5.71 0.00 63.14 5.11 12.45 1.16 1.32 1.27 2.50 13.04 0.00 60.75 4.35 12.02 1.83 3.96 3.88 7.44 5.77 0.00 63.53 4.68 12.72 1.02 1.36 1.32 2.37 12.99 0.00 61.19 3.98 12.29 1.60 4.11 4.01 7.06 5.75 0.00 63.38 4.90 12.41 1.00 1.39 1.30 2.39 13.24 0.00 61.11 4.18 12.01 1.58 4.17 3.98 7.11 5.87 0.00 63.83 4.43 12.51 0.96 1.37 1.32 2.33 13.25 0.00 61.60 3.78 12.12 1.51 4.15 4.03 6.92 5.88 0.00 63.05 5.17 12.62 1.09 1.36 1.34 2.36 13.02 0.00 60.74 4.41 12.19 1.71 4.09 4.09 7.00 5.77 0.00 62.52 5.44 13.35 1.12 1.40 1.52 2.20 12.46 0.00 60.00 4.61 12.84 1.75 4.21 4.60 6.50 5.50 0.00 63.06 5.23 13.11 1.03 1.35 1.48 2.22 12.52 0.00 60.61 4.45 12.64 1.62 4.06 4.51 6.58 5.53 0.00 62.86 4.76 13.92 1.09 1.51 1.77 1.92 12.18 0.00 60.06 4.03 13.34 1.70 4.52 5.35 5.65 5.35 0.00 62.36 5.27 13.89 1.03 1.81 2.48 1.61 11.55 0.00 58.58 4.38 13.09 1.57 5.33 7.38 4.68 4.99 0.00 62.42 4.95 14.49 0.96 1.90 2.97 1.36 10.93 0.00 58.05 4.08 13.53 1.46 5.54 8.76 3.91 4.67 0.00 Average 62.09 5.39 14.26 1.01 1.97 2.91 1.36 11.01 0.00 57.77 4.44 13.32 1.54 5.73 8.59 3.91 4.71 0.00

PAGE 192

172Table C-9: Average EMPA data for LMSX-9. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 66.82 4.55 13.26 2.45 0.43 1.86 10.62 0.00 64.35 3.88 12.82 7.39 1.33 5.53 4.70 0.00 66.51 4.59 13.52 2.48 0.48 1.85 10.56 0.00 63.95 3.91 13.06 7.47 1.45 5.49 4.67 0.00 66.91 4.47 12.70 2.16 0.33 2.26 11.17 0.00 64.63 3.82 12.31 6.54 1.00 6.73 4.96 0.00 67.12 4.28 12.19 1.67 0.15 2.82 11.76 0.00 65.18 3.68 11.89 5.10 0.47 8.43 5.25 0.00 66.86 4.60 12.15 1.46 0.10 3.11 11.71 0.00 64.93 3.95 11.84 4.44 0.30 9.31 5.23 0.00 66.69 4.39 11.89 1.53 0.14 3.26 12.10 0.00 64.52 3.76 11.55 4.65 0.42 9.71 5.38 0.00 66.52 4.46 11.96 1.56 0.08 3.30 12.15 0.00 64.38 3.83 11.60 4.72 0.23 9.83 5.40 0.00 66.41 4.69 12.28 1.60 0.08 3.11 11.82 0.00 64.35 4.03 11.94 4.86 0.26 9.28 5.26 0.00 66.49 4.54 12.11 1.55 0.11 3.19 12.01 0.00 64.41 3.90 11.77 4.72 0.33 9.54 5.35 0.00 66.45 4.81 12.25 1.54 0.13 3.07 11.76 0.00 64.45 4.12 11.93 4.67 0.40 9.18 5.24 0.00 66.36 4.75 12.42 1.64 0.11 3.02 11.70 0.00 64.29 4.07 12.08 4.98 0.34 9.03 5.21 0.00 66.40 4.71 12.28 1.63 0.15 3.02 11.80 0.00 64.31 4.04 11.95 4.95 0.47 9.03 5.25 0.00 66.47 4.59 12.34 1.69 0.10 2.97 11.83 0.00 64.44 3.94 12.01 5.14 0.32 8.88 5.27 0.00 66.05 5.07 13.14 1.81 0.21 2.47 11.24 0.00 64.21 4.37 12.83 5.52 0.65 7.40 5.02 0.00 66.07 4.99 12.96 1.87 0.20 2.53 11.38 0.00 64.13 4.29 12.62 5.68 0.61 7.58 5.08 0.00 65.76 5.06 13.16 1.94 0.23 2.47 11.38 0.00 63.79 4.35 12.81 5.88 0.72 7.38 5.07 0.00 66.53 4.42 11.92 1.69 0.11 3.10 12.24 0.00 64.45 3.79 11.59 5.14 0.33 9.25 5.45 0.00 66.37 4.62 12.37 1.57 0.10 3.15 11.82 0.00 64.28 3.96 12.03 4.76 0.30 9.41 5.26 0.00 66.57 4.45 11.98 1.51 0.08 3.31 12.11 0.00 64.45 3.82 11.64 4.57 0.26 9.87 5.39 0.00 66.07 5.22 12.47 1.45 0.05 3.19 11.55 0.00 64.12 4.49 12.15 4.42 0.14 9.54 5.15 0.00 66.35 4.72 12.12 1.51 0.10 3.32 11.88 0.00 64.14 4.04 11.76 4.58 0.31 9.89 5.28 0.00 66.57 4.62 12.06 1.43 0.11 3.21 12.00 0.00 64.64 3.97 11.75 4.31 0.34 9.59 5.36 0.00 66.39 4.68 12.46 1.58 0.15 2.97 11.78 0.00 64.45 4.02 12.14 4.80 0.47 8.88 5.25 0.00 66.78 4.28 11.85 1.57 0.10 3.23 12.18 0.00 64.67 3.68 11.53 4.78 0.30 9.63 5.42 0.00 66.58 4.70 12.43 1.64 0.14 2.95 11.57 0.00 64.53 4.03 12.09 4.97 0.42 8.80 5.15 0.00 66.70 4.75 12.33 1.66 0.14 2.90 11.51 0.00 64.66 4.08 12.00 5.02 0.44 8.66 5.13 0.00 66.92 4.56 12.38 1.88 0.26 2.55 11.44 0.00 64.83 3.92 12.04 5.71 0.80 7.62 5.10 0.00 66.56 4.58 13.42 2.28 0.40 2.07 10.69 0.00 64.13 3.90 12.98 6.89 1.22 6.14 4.73 0.00 66.59 4.66 13.55 2.44 0.44 1.88 10.44 0.00 64.06 3.97 13.08 7.36 1.35 5.57 4.61 0.00 Average 66.76 4.45 13.21 2.43 0.45 1.89 10.80 0.00 64.31 3.79 12.77 7.33 1.40 5.62 4.78 0.00

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173Table C-10: Average EMPA data for LMSX-10. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 64.30 4.78 14.37 2.35 1.91 1.75 10.52 0.00 60.31 3.97 13.53 6.91 5.69 5.05 4.54 0.00 64.74 4.74 13.96 2.40 1.84 1.76 10.57 0.00 60.75 3.94 13.14 7.06 5.46 5.09 4.55 0.00 63.24 4.46 13.84 4.01 3.07 2.97 8.58 0.00 60.50 3.93 13.28 7.01 5.44 5.29 4.57 0.00 65.00 4.53 13.38 2.27 1.53 2.08 11.21 0.00 61.35 3.79 12.68 6.70 4.58 6.05 4.86 0.00 65.39 4.55 12.98 1.87 1.17 2.38 11.66 0.00 62.44 3.85 12.44 5.60 3.53 7.02 5.12 0.00 65.33 4.53 12.74 1.65 0.88 2.85 12.01 0.00 62.58 3.84 12.24 4.95 2.67 8.43 5.29 0.00 65.79 4.20 12.16 1.56 0.74 3.26 12.27 0.00 62.85 3.58 11.66 4.68 2.24 9.63 5.39 0.00 66.62 3.38 11.06 1.48 0.51 3.90 13.05 0.00 63.47 2.85 10.57 4.40 1.52 11.46 5.72 0.00 65.62 4.12 11.99 1.61 0.68 3.43 12.55 0.00 62.60 3.47 11.47 4.80 2.03 10.11 5.50 0.00 64.45 5.16 13.39 1.59 0.92 2.89 11.58 0.00 61.61 4.37 12.85 4.75 2.77 8.55 5.09 0.00 65.91 3.97 11.82 1.61 0.70 3.45 12.54 0.00 62.82 3.35 11.30 4.81 2.08 10.14 5.50 0.00 65.45 4.54 12.26 1.62 0.76 3.27 12.08 0.00 62.38 3.83 11.73 4.85 2.31 9.62 5.29 0.00 65.07 4.64 12.59 1.62 0.83 3.19 12.05 0.00 62.03 3.92 12.05 4.84 2.49 9.39 5.28 0.00 65.22 4.64 12.48 1.63 0.75 3.16 12.12 0.00 62.32 3.93 11.96 4.89 2.26 9.32 5.33 0.00 65.07 4.77 12.69 1.50 0.70 3.27 12.01 0.00 62.25 4.04 12.19 4.48 2.12 9.64 5.28 0.00 65.63 4.24 11.87 1.50 0.55 3.62 12.59 0.00 62.69 3.59 11.38 4.50 1.67 10.65 5.53 0.00 65.65 4.28 11.71 1.44 0.54 3.64 12.74 0.00 62.83 3.62 11.25 4.32 1.63 10.75 5.60 0.00 65.43 4.41 12.20 1.47 0.53 3.50 12.45 0.00 62.67 3.74 11.73 4.41 1.63 10.34 5.48 0.00 65.51 4.42 11.96 1.44 0.48 3.52 12.67 0.00 62.93 3.76 11.54 4.31 1.46 10.41 5.59 0.00 66.24 3.71 11.31 1.45 0.39 3.83 13.07 0.00 63.42 3.15 10.87 4.33 1.17 11.31 5.75 0.00 66.06 3.84 11.35 1.46 0.41 3.75 13.12 0.00 63.31 3.26 10.92 4.40 1.24 10.99 5.78 0.00 65.27 4.59 12.52 1.47 0.63 3.17 12.35 0.00 62.80 3.91 12.09 4.42 1.93 9.39 5.47 0.00 65.31 4.52 12.37 1.63 0.78 3.12 12.27 0.00 62.46 3.82 11.87 4.87 2.36 9.22 5.40 0.00 65.37 4.28 12.25 1.59 0.76 3.24 12.50 0.00 62.50 3.62 11.76 4.77 2.30 9.55 5.50 0.00 65.57 4.52 12.49 1.59 0.75 3.08 12.01 0.00 62.77 3.82 11.99 4.77 2.26 9.09 5.28 0.00 65.38 4.56 12.58 1.65 0.85 2.90 12.08 0.00 62.62 3.90 12.10 4.94 2.58 8.57 5.32 0.00 65.07 4.76 13.31 1.84 1.05 2.46 11.50 0.00 62.21 4.03 12.78 5.51 3.18 7.26 5.05 0.00 64.81 4.64 13.30 2.22 1.45 2.17 11.42 0.00 61.30 3.89 12.63 6.56 4.33 6.33 4.96 0.00 64.69 4.87 13.74 2.39 1.77 1.88 10.66 0.00 60.68 4.05 12.94 7.04 5.26 5.44 4.60 0.00 Average 64.87 4.62 13.72 2.41 1.85 1.84 10.68 0.00 60.78 3.83 12.91 7.07 5.49 5.32 4.60 0.00

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174Table C-11: Average EMPA data for LMSX-11. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 60.38 5.90 15.05 1.80 5.09 1.15 10.62 0.00 54.42 4.71 13.62 5.08 14.55 3.20 4.40 0.00 60.68 5.21 15.02 1.82 4.81 1.31 11.16 0.00 54.93 4.17 13.65 5.15 13.81 3.65 4.64 0.00 60.09 6.23 15.47 1.73 4.71 1.29 10.48 0.00 54.51 5.00 14.07 4.91 13.50 3.63 4.37 0.00 61.88 5.34 14.65 1.35 2.88 1.72 12.19 0.00 58.70 4.47 13.90 3.98 8.57 5.04 5.33 0.00 62.31 5.65 14.40 1.11 2.26 1.94 12.34 0.00 59.96 4.79 13.85 3.34 6.81 5.79 5.47 0.00 66.16 3.49 11.12 0.97 0.85 2.86 14.55 0.00 65.10 3.04 10.98 2.98 2.65 8.66 6.58 0.01 64.84 3.78 11.44 0.90 0.78 3.21 15.05 0.00 63.73 3.27 11.27 2.77 2.43 9.73 6.80 0.00 65.04 3.74 11.36 0.94 0.91 3.00 15.02 0.00 63.95 3.26 11.21 2.88 2.82 9.09 6.79 0.00 62.52 5.54 13.20 0.99 1.57 2.50 13.67 0.00 60.84 4.77 12.89 3.02 4.85 7.51 6.12 0.00 65.22 3.83 11.60 1.04 1.13 2.72 14.46 0.00 63.87 3.32 11.40 3.17 3.51 8.21 6.51 0.00 63.74 4.97 12.33 1.09 1.43 2.50 13.93 0.00 62.14 4.29 12.07 3.33 4.42 7.52 6.24 0.00 64.36 4.10 12.06 1.03 1.12 2.74 14.59 0.00 63.09 3.46 11.86 3.15 3.49 8.27 6.57 0.00 63.46 5.02 12.25 1.02 1.27 2.69 14.28 0.00 62.04 4.34 12.02 3.13 3.93 8.12 6.42 0.00 64.06 4.37 12.16 1.04 1.12 2.83 14.43 0.00 62.63 3.78 11.93 3.18 3.46 8.52 6.48 0.00 65.23 3.90 11.05 0.91 0.66 3.23 15.02 0.00 64.23 3.40 10.92 2.79 2.06 9.79 6.80 0.00 64.05 4.18 12.19 0.98 0.96 3.09 14.54 0.00 62.62 3.61 11.95 3.01 2.97 9.31 6.53 0.00 63.73 4.86 12.11 0.99 1.16 2.82 14.33 0.00 62.37 4.19 11.87 3.02 3.58 8.52 6.45 0.00 63.85 4.79 12.36 1.08 1.36 2.56 13.98 0.00 62.27 4.14 12.11 3.31 4.20 7.70 6.27 0.00 62.71 5.52 13.07 1.03 1.66 2.47 13.53 0.00 60.86 4.74 12.72 3.14 5.11 7.39 6.04 0.00 64.58 3.93 11.92 1.17 1.32 2.58 14.50 0.00 63.03 3.39 11.66 3.57 4.07 7.78 6.51 0.00 62.36 5.73 13.79 1.22 2.17 2.15 12.57 0.00 59.82 4.83 13.21 3.66 6.52 6.39 5.56 0.00 62.90 5.11 13.27 1.22 2.06 2.19 13.25 0.00 60.58 4.34 12.81 3.66 6.24 6.50 5.87 0.00 63.95 4.63 12.27 1.17 1.70 2.41 13.87 0.00 61.98 3.98 11.93 3.53 5.20 7.20 6.18 0.00 64.12 4.25 12.60 1.14 1.59 2.47 13.83 0.00 62.22 3.64 12.25 3.46 4.86 7.40 6.17 0.00 65.20 3.83 11.23 1.09 1.02 2.83 14.81 0.00 63.92 3.32 11.04 3.34 3.16 8.55 6.67 0.00 65.41 3.45 11.63 1.07 1.15 2.74 14.55 0.00 63.97 2.99 11.34 3.27 3.55 8.27 6.54 0.00 62.28 5.57 14.25 1.30 2.57 1.78 12.25 0.00 59.41 4.70 13.64 3.87 7.77 5.24 5.37 0.00 61.43 5.57 14.79 1.57 3.78 1.47 11.39 0.00 56.95 4.58 13.76 4.54 11.10 4.21 4.86 0.00 60.43 5.83 15.04 1.82 4.89 1.26 10.73 0.00 54.58 4.66 13.63 5.15 14.01 3.51 4.45 0.00 Average 60.24 5.80 15.26 1.71 5.16 1.18 10.65 0.00 54.30 4.63 13.80 4.82 14.75 3.29 4.41 0.00

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175Table C-12: Average EMPA data for LMSX-12. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 62.70 5.07 15.03 2.05 3.03 1.81 10.31 0.00 57.72 4.13 13.89 5.90 8.85 5.15 4.36 0.00 62.49 5.31 14.98 1.98 3.11 1.84 10.30 0.00 57.49 4.33 13.83 5.71 9.08 5.21 4.35 0.00 62.60 5.20 14.92 1.90 2.62 2.08 10.69 0.00 58.09 4.27 13.90 5.52 7.70 5.97 4.56 0.00 63.01 5.77 14.45 1.65 1.54 2.50 11.08 0.00 59.78 4.86 13.76 4.90 4.55 7.33 4.83 0.00 63.81 4.31 13.69 1.53 1.63 2.95 12.09 0.00 60.27 3.59 12.94 4.50 4.81 8.64 5.26 0.00 64.09 4.58 13.16 1.40 1.37 3.02 12.33 0.00 60.90 3.84 12.54 4.17 4.31 8.85 5.39 0.00 63.16 5.11 13.93 1.44 1.40 3.04 11.91 0.00 59.89 4.29 13.25 4.29 4.21 8.87 5.19 0.00 63.68 5.30 13.06 1.39 1.18 3.31 12.09 0.00 60.47 4.46 12.44 4.13 3.54 9.69 5.28 0.00 63.18 5.10 13.58 1.32 1.14 3.38 12.31 0.00 60.10 4.30 12.97 3.92 3.43 9.90 5.38 0.00 64.54 4.36 12.30 1.23 0.75 3.82 12.99 0.00 61.63 3.68 11.79 3.67 2.27 11.26 5.71 0.00 63.46 4.86 13.11 1.32 1.07 3.49 12.70 0.00 60.43 4.09 12.53 3.93 3.24 10.22 5.56 0.00 63.78 5.15 13.09 1.31 1.17 3.28 12.22 0.00 60.75 4.34 12.51 3.89 3.54 9.63 5.35 0.00 65.03 3.80 12.07 1.28 0.80 3.52 13.51 0.00 62.48 3.23 11.64 3.84 2.43 10.42 5.96 0.00 63.51 5.21 13.30 1.37 1.32 3.10 12.20 0.00 60.44 4.39 12.70 4.09 3.97 9.08 5.33 0.00 64.02 4.40 12.96 1.27 1.09 3.31 12.95 0.00 61.26 3.73 12.44 3.80 3.31 9.76 5.70 0.00 64.07 4.62 12.56 1.28 1.09 3.41 12.94 0.00 61.16 3.90 12.03 3.81 3.37 10.04 5.68 0.00 64.31 4.11 12.71 1.29 0.99 3.50 13.08 0.00 61.42 3.47 12.19 3.85 3.01 10.32 5.74 0.00 63.13 5.44 13.45 1.35 1.35 3.17 12.13 0.00 59.98 4.57 12.82 4.01 4.04 9.29 5.30 0.00 64.18 4.19 12.80 1.26 0.94 3.54 13.09 0.00 61.38 3.55 12.29 3.77 2.84 10.43 5.75 0.00 63.53 5.27 13.31 1.39 1.27 3.23 12.00 0.00 60.31 4.41 12.66 4.12 3.81 9.44 5.24 0.00 63.08 5.26 13.76 1.48 1.41 3.07 11.94 0.00 59.74 4.40 13.06 4.38 4.24 8.97 5.20 0.00 63.57 5.38 13.26 1.43 1.30 3.13 11.94 0.00 60.35 4.52 12.63 4.23 3.90 9.14 5.21 0.00 63.80 4.73 13.24 1.36 1.11 3.25 12.52 0.00 60.88 3.99 12.68 4.05 3.35 9.56 5.49 0.00 63.32 5.47 13.68 1.43 1.40 3.09 11.62 0.00 59.93 4.59 12.99 4.23 4.19 9.01 5.05 0.00 63.79 4.46 13.35 1.51 1.47 3.23 12.17 0.00 60.13 3.72 12.63 4.46 4.38 9.41 5.27 0.00 63.56 4.80 13.32 1.56 1.72 3.06 11.98 0.00 59.74 3.98 12.53 4.57 5.07 8.93 5.18 0.00 63.10 4.91 14.30 1.72 2.16 2.58 11.24 0.00 58.92 4.06 13.40 5.02 6.36 7.42 4.83 0.00 62.51 5.62 14.56 1.86 2.70 2.08 10.68 0.00 58.00 4.61 13.55 5.39 7.92 5.97 4.56 0.00 62.56 5.17 15.12 2.02 2.97 1.85 10.30 0.00 57.66 4.22 13.98 5.84 8.68 5.25 4.36 0.00 Average 62.46 5.41 14.69 2.07 3.02 1.85 10.51 0.00 57.53 4.41 13.58 5.97 8.80 5.26 4.45 0.00

PAGE 196

176Table C-13: Average EMPA data for LMSX-13. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Hf Ni Cr Co W Re Ta Al Hf 62.93 4.95 14.46 1.93 3.34 0.70 11.70 0.00 59.38 4.14 13.69 5.69 10.01 2.03 5.07 0.00 62.95 5.18 14.35 1.95 3.32 0.78 11.48 0.00 59.27 4.32 13.56 5.74 9.89 2.25 4.97 0.00 63.46 4.94 13.86 1.79 2.83 0.87 12.26 0.00 60.66 4.18 13.29 5.37 8.55 2.56 5.39 0.00 64.27 4.89 13.17 1.39 1.83 1.18 13.28 0.00 63.27 4.25 12.98 4.24 5.64 3.59 6.02 0.00 65.21 4.52 12.08 1.12 1.12 1.49 14.46 0.00 65.46 4.02 12.16 3.51 3.55 4.63 6.67 0.00 65.45 4.43 11.48 1.01 0.77 1.71 15.16 0.00 66.30 3.98 11.67 3.20 2.48 5.33 7.06 0.00 65.10 4.61 11.94 1.01 0.91 1.64 14.80 0.00 65.71 4.12 12.09 3.18 2.92 5.11 6.87 0.00 64.59 5.21 12.33 1.04 1.03 1.52 14.29 0.00 65.02 4.64 12.44 3.28 3.29 4.70 6.61 0.00 64.96 4.57 12.08 1.09 0.98 1.56 14.76 0.00 65.44 4.07 12.21 3.46 3.14 4.84 6.83 0.00 65.29 4.58 11.39 1.00 0.83 1.81 15.07 0.00 65.90 4.09 11.53 3.17 2.66 5.65 7.00 0.00 64.60 4.94 12.20 1.05 0.99 1.69 14.52 0.00 64.89 4.40 12.30 3.31 3.15 5.24 6.71 0.00 62.18 7.29 14.49 0.93 1.36 1.16 12.58 0.00 62.31 6.47 14.58 2.92 4.33 3.60 5.79 0.00 64.98 4.58 11.99 1.02 0.88 1.66 14.88 0.00 65.61 4.10 12.15 3.25 2.81 5.18 6.90 0.00 64.80 5.12 11.71 0.96 0.78 1.74 14.90 0.00 65.62 4.60 11.90 3.03 2.50 5.42 6.94 0.00 66.00 3.86 10.91 0.86 0.53 2.05 15.78 0.00 67.13 3.48 11.14 2.75 1.70 6.42 7.37 0.00 64.32 5.18 12.16 0.97 0.86 1.68 14.82 0.00 65.05 4.63 12.35 3.09 2.75 5.24 6.89 0.00 64.46 4.94 12.60 1.07 1.09 1.47 14.38 0.00 64.83 4.40 12.71 3.37 3.48 4.57 6.65 0.00 64.73 4.82 12.05 1.11 1.02 1.55 14.73 0.00 65.17 4.30 12.17 3.49 3.25 4.79 6.81 0.00 65.63 4.14 11.61 1.01 0.91 1.63 15.06 0.00 66.32 3.71 11.77 3.20 2.92 5.08 7.00 0.00 64.95 4.70 11.75 1.02 0.83 1.68 15.08 0.00 65.73 4.21 11.93 3.23 2.64 5.23 7.01 0.00 65.14 4.72 11.93 1.01 0.94 1.57 14.69 0.00 65.76 4.22 12.09 3.20 3.03 4.88 6.82 0.00 64.79 4.76 11.89 1.05 0.86 1.64 15.02 0.00 65.50 4.26 12.07 3.32 2.74 5.13 6.98 0.00 64.88 4.49 12.09 1.02 0.96 1.67 14.90 0.00 65.41 4.01 12.23 3.22 3.06 5.18 6.90 0.00 65.54 4.46 11.34 0.98 0.71 1.84 15.13 0.00 66.33 3.99 11.51 3.10 2.29 5.73 7.04 0.00 65.32 4.39 12.08 0.99 0.93 1.58 14.70 0.00 65.98 3.92 12.25 3.12 2.97 4.94 6.83 0.00 65.16 4.50 11.90 1.20 1.12 1.51 14.60 0.00 65.30 4.05 11.96 3.76 3.57 4.69 6.73 0.00 64.00 5.04 13.56 1.56 2.08 1.04 12.72 0.00 62.40 4.34 13.26 4.75 6.42 3.13 5.70 0.00 63.14 5.08 13.91 1.82 2.79 0.92 12.32 0.00 60.32 4.29 13.33 5.43 8.51 2.72 5.41 0.00 63.22 4.70 14.21 1.93 3.39 0.76 11.68 0.00 59.49 3.92 13.52 5.70 10.10 2.22 5.05 0.00 Average 62.89 5.20 14.15 2.01 3.34 0.75 11.65 0.00 59.18 4.34 13.36 5.94 9.97 2.18 5.04 0.00

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177Table C-14: Average EMPA data for LMSX-14. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Ti Hf Ni Cr Co W Re Ta Al Ti Hf 65.14 5.03 14.64 1.78 2.50 0.79 9.45 0.72 0.00 61.98 4.24 13.97 5.28 7.51 2.34 4.10 0.56 0.00 64.76 5.59 14.50 1.76 2.43 0.82 9.42 0.72 0.00 61.75 4.72 13.86 5.25 7.30 2.41 4.13 0.57 0.00 65.48 5.23 14.06 1.75 2.23 0.86 9.68 0.73 0.00 62.71 4.43 13.51 5.24 6.75 2.53 4.26 0.57 0.00 65.69 5.34 13.55 1.45 1.70 0.96 10.39 0.90 0.00 64.12 4.62 13.27 4.45 5.26 2.91 4.66 0.72 0.00 65.76 4.94 14.07 1.39 1.60 1.06 10.24 0.94 0.00 64.19 4.27 13.79 4.25 4.97 3.19 4.60 0.75 0.00 65.46 5.58 13.67 1.26 1.54 1.10 10.49 0.91 0.00 64.27 4.84 13.44 3.89 4.76 3.33 4.74 0.73 0.00 66.20 4.67 13.13 1.27 1.39 1.24 11.03 1.07 0.00 65.18 4.06 12.94 3.88 4.27 3.79 5.01 0.87 0.00 65.73 5.37 13.14 1.18 1.42 1.25 10.73 1.15 0.00 64.74 4.67 12.95 3.62 4.46 3.83 4.88 0.93 0.00 67.06 4.18 12.47 0.99 0.92 1.45 11.66 1.27 0.00 66.98 3.69 12.48 3.08 2.88 4.48 5.37 1.04 0.00 65.84 5.38 13.18 1.03 1.16 1.25 11.01 1.15 0.00 65.47 4.74 13.15 3.19 3.64 3.84 5.04 0.94 0.00 66.05 4.82 13.34 1.12 1.23 1.25 11.01 1.19 0.00 65.42 4.22 13.25 3.47 3.82 3.84 5.03 0.96 0.00 66.19 4.97 12.86 1.01 1.06 1.33 11.34 1.22 0.00 65.96 4.38 12.86 3.16 3.33 4.11 5.21 1.00 0.00 66.27 4.83 13.00 0.93 0.97 1.39 11.40 1.23 0.00 66.26 4.27 13.04 2.89 3.05 4.25 5.25 1.01 0.00 65.54 5.64 13.05 1.06 1.02 1.32 11.10 1.28 0.00 65.30 4.97 13.05 3.29 3.20 4.06 5.10 1.04 0.00 66.62 4.55 12.64 1.06 0.91 1.37 11.46 1.40 0.00 66.52 4.02 12.66 3.30 2.85 4.23 5.28 1.14 0.00 65.41 5.15 12.71 0.91 0.73 1.41 12.29 1.39 0.00 66.07 4.61 12.88 2.87 2.34 4.38 5.70 1.15 0.00 66.05 4.41 12.13 0.91 0.66 1.45 12.64 1.76 0.00 66.87 3.96 12.33 2.87 2.11 4.52 5.88 1.45 0.01 66.22 4.61 12.06 0.82 0.62 1.57 12.55 1.55 0.00 67.03 4.13 12.25 2.59 2.00 4.89 5.84 1.28 0.00 65.65 4.73 13.02 0.95 0.80 1.35 12.01 1.50 0.00 66.13 4.21 13.16 2.99 2.53 4.19 5.57 1.23 0.00 65.70 5.12 12.60 0.94 0.78 1.40 12.08 1.39 0.00 66.20 4.57 12.74 2.95 2.48 4.34 5.60 1.14 0.00 65.67 4.71 12.91 0.89 0.87 1.37 12.14 1.45 0.00 66.15 4.18 13.03 2.80 2.75 4.27 5.63 1.19 0.00 65.25 5.26 13.16 0.98 0.96 1.24 11.90 1.25 0.00 65.55 4.67 13.27 3.07 3.07 3.84 5.50 1.03 0.00 65.63 4.77 13.10 1.18 1.10 1.19 11.81 1.22 0.00 65.45 4.21 13.11 3.68 3.46 3.68 5.43 0.99 0.00 66.30 4.59 12.21 1.04 0.80 1.40 12.36 1.29 0.01 66.65 4.08 12.31 3.27 2.56 4.33 5.71 1.06 0.02 65.86 4.51 12.98 1.03 0.92 1.30 12.13 1.27 0.00 66.10 4.01 13.07 3.23 2.93 4.01 5.60 1.04 0.00 66.52 4.46 12.26 1.04 0.81 1.38 12.33 1.20 0.00 66.86 3.96 12.35 3.26 2.58 4.29 5.70 0.98 0.00 65.92 4.41 13.45 1.45 1.38 1.05 11.42 0.91 0.00 64.96 3.85 13.30 4.48 4.32 3.19 5.17 0.73 0.00 64.33 5.40 14.55 1.79 2.32 0.74 10.14 0.73 0.00 61.73 4.59 14.01 5.38 7.07 2.18 4.47 0.58 0.00 64.08 5.04 15.16 1.97 2.82 0.61 9.69 0.64 0.00 60.62 4.23 14.40 5.82 8.45 1.77 4.21 0.49 0.00 Average 63.77 5.44 15.15 1.97 2.88 0.66 9.50 0.63 0.00 60.15 4.55 14.34 5.82 8.60 1.93 4.12 0.48 0.00

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178Table C-15: Average EMPA data for LMSX-15. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Ti Hf Ni Cr Co W Re Ta Al Ti Hf 62.84 5.26 14.86 1.97 3.29 1.26 9.95 0.59 0.00 58.23 4.32 13.82 5.72 9.66 3.58 4.20 0.42 0.00 62.35 5.61 14.85 2.08 3.22 1.29 9.96 0.63 0.00 57.71 4.60 13.80 6.03 9.46 3.69 4.24 0.48 0.00 63.69 5.16 14.16 1.67 2.33 1.55 10.69 0.75 0.00 60.43 4.33 13.48 4.97 7.02 4.53 4.66 0.58 0.00 64.15 5.12 13.36 1.40 1.56 2.02 11.43 0.97 0.00 61.89 4.37 12.92 4.20 4.75 6.02 5.07 0.77 0.00 64.99 4.46 12.36 1.11 1.01 2.37 12.48 1.21 0.00 63.68 3.87 12.15 3.41 3.13 7.17 5.62 0.97 0.00 64.64 4.70 12.17 1.28 1.08 2.42 12.40 1.32 0.00 62.96 4.06 11.89 3.90 3.34 7.26 5.55 1.05 0.00 65.06 4.02 12.20 1.06 0.92 2.59 12.77 1.38 0.00 63.73 3.48 11.98 3.25 2.87 7.83 5.75 1.11 0.00 64.19 4.98 12.54 1.07 1.04 2.46 12.32 1.39 0.00 62.80 4.31 12.31 3.28 3.21 7.42 5.54 1.12 0.00 65.14 4.23 12.30 1.09 0.98 2.56 12.37 1.33 0.00 63.63 3.65 12.05 3.33 3.00 7.73 5.56 1.06 0.00 63.21 5.80 13.28 1.24 1.37 2.24 11.62 1.24 0.00 61.27 4.97 12.91 3.77 4.22 6.70 5.18 0.98 0.00 64.57 4.72 12.61 1.14 1.14 2.43 12.00 1.39 0.00 62.86 4.07 12.33 3.47 3.52 7.29 5.37 1.10 0.00 61.90 5.84 12.91 0.87 1.10 2.33 11.06 1.61 2.37 58.14 4.85 12.19 2.63 3.32 6.66 4.78 1.20 6.22 63.96 5.03 12.85 1.14 1.15 2.38 12.17 1.32 0.00 62.40 4.34 12.58 3.47 3.54 7.16 5.46 1.05 0.00 64.36 5.03 12.33 1.10 1.03 2.51 12.26 1.36 0.00 62.86 4.35 12.08 3.37 3.18 7.58 5.50 1.08 0.00 63.75 5.34 13.17 1.13 1.23 2.33 11.70 1.34 0.00 62.00 4.61 12.86 3.45 3.80 6.99 5.23 1.06 0.00 65.09 4.34 11.47 1.10 0.77 2.65 13.15 1.41 0.00 63.99 3.78 11.32 3.39 2.40 8.04 5.94 1.13 0.00 64.30 4.97 12.86 0.98 1.16 2.41 12.00 1.33 0.00 62.83 4.29 12.59 2.99 3.59 7.27 5.39 1.06 0.00 63.52 5.08 12.34 1.16 1.04 2.37 12.14 2.36 0.00 62.19 4.40 12.12 3.57 3.21 7.15 5.46 1.89 0.00 63.13 5.05 12.46 1.05 1.05 2.38 11.80 3.08 0.00 61.91 4.36 12.24 3.21 3.25 7.21 5.33 2.49 0.00 65.88 3.56 10.80 1.04 0.50 2.98 13.65 1.59 0.00 64.92 3.10 10.67 3.20 1.57 9.07 6.18 1.27 0.00 64.85 4.34 12.16 1.09 1.02 2.57 12.56 1.42 0.00 63.34 3.75 11.91 3.33 3.14 7.74 5.64 1.14 0.00 65.31 4.11 11.30 1.04 0.65 2.78 13.33 1.48 0.00 64.34 3.59 11.18 3.19 2.03 8.44 6.03 1.19 0.00 65.81 3.53 11.29 0.90 0.55 2.94 13.31 1.67 0.00 64.91 3.07 11.18 2.77 1.69 8.94 6.03 1.34 0.00 65.27 4.00 11.10 0.90 0.47 3.06 13.49 1.70 0.00 64.45 3.49 10.99 2.79 1.45 9.34 6.12 1.37 0.00 64.78 4.17 12.21 0.94 0.74 2.80 12.83 1.52 0.00 63.64 3.63 12.04 2.90 2.31 8.47 5.79 1.22 0.00 63.16 5.96 13.58 1.12 1.28 2.26 11.33 1.31 0.00 61.38 5.12 13.24 3.41 3.96 6.78 5.06 1.04 0.00 65.18 3.99 12.35 1.11 1.07 2.54 12.46 1.30 0.00 63.57 3.43 12.06 3.37 3.26 7.66 5.59 1.04 0.00 63.51 5.57 13.81 1.70 2.08 1.71 10.82 0.81 0.00 60.45 4.69 13.19 5.04 6.26 5.02 4.74 0.63 0.00 63.59 5.00 14.09 1.87 2.94 1.41 10.38 0.69 0.00 59.42 4.14 13.22 5.46 8.72 4.05 4.47 0.53 0.00 Average 62.53 5.70 14.75 2.07 3.29 1.21 9.85 0.60 0.00 57.87 4.67 13.71 6.01 9.66 3.45 4.19 0.45 0.00

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179Table C-16: Average EMPA data for LMSX-16. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Ru Hf Ni Cr Co W Re Ta Al Ru Hf 61.79 5.50 14.62 1.76 3.18 1.31 10.77 1.02 0.00 57.37 4.52 13.68 5.11 9.35 3.75 4.59 1.63 0.00 61.88 4.96 14.97 2.01 3.26 1.28 10.59 1.04 0.00 57.01 4.05 13.85 5.79 9.53 3.64 4.48 1.65 0.00 62.39 5.37 14.31 1.66 2.80 1.46 11.11 0.91 0.00 58.46 4.45 13.46 4.87 8.31 4.21 4.78 1.47 0.00 62.65 5.08 14.19 1.56 2.06 1.69 11.93 0.84 0.00 59.70 4.28 13.57 4.66 6.23 4.98 5.22 1.37 0.00 63.17 5.13 13.55 1.31 1.49 1.94 12.38 1.02 0.00 60.99 4.39 13.14 3.96 4.57 5.77 5.50 1.69 0.00 63.66 4.40 13.11 1.30 1.12 2.40 13.12 0.89 0.00 61.63 3.77 12.74 3.94 3.43 7.18 5.84 1.48 0.00 63.40 5.10 12.79 1.18 1.14 2.45 13.17 0.76 0.00 61.55 4.38 12.46 3.60 3.51 7.34 5.88 1.27 0.00 63.07 4.84 13.32 1.19 1.16 2.50 12.92 0.99 0.00 60.94 4.14 12.92 3.61 3.56 7.45 5.73 1.65 0.00 62.79 5.61 13.10 1.00 1.29 2.35 12.88 0.97 0.00 60.97 4.83 12.77 3.05 3.97 7.03 5.75 1.62 0.00 62.96 4.84 13.29 1.24 1.23 2.45 12.99 1.00 0.00 60.77 4.14 12.87 3.73 3.77 7.28 5.77 1.66 0.00 63.28 5.24 12.68 1.02 1.17 2.49 13.16 0.97 0.00 61.48 4.50 12.36 3.09 3.61 7.45 5.88 1.63 0.00 64.10 4.05 12.59 1.26 0.90 2.68 13.64 0.78 0.00 62.23 3.48 12.27 3.83 2.77 8.02 6.09 1.31 0.00 63.27 5.20 12.78 1.19 1.29 2.37 12.96 0.95 0.00 61.19 4.45 12.40 3.60 3.93 7.09 5.76 1.58 0.00 63.04 4.62 13.11 1.35 1.20 2.54 13.21 0.94 0.00 60.73 3.94 12.67 4.05 3.66 7.53 5.85 1.56 0.00 62.98 5.48 13.05 1.11 1.27 2.31 12.97 0.83 0.00 61.20 4.71 12.71 3.36 3.91 6.93 5.80 1.38 0.00 63.24 4.70 13.22 1.22 1.29 2.25 13.29 0.79 0.00 61.41 4.04 12.88 3.69 3.98 6.73 5.93 1.32 0.00 63.70 4.80 12.52 1.10 1.23 2.51 13.27 0.87 0.00 61.73 4.12 12.17 3.32 3.78 7.52 5.91 1.45 0.00 63.75 3.89 12.35 1.19 1.03 2.65 14.12 0.92 0.00 61.96 3.43 12.05 3.59 3.16 7.95 6.31 1.55 0.00 63.31 5.11 12.66 1.07 1.24 2.41 13.29 0.90 0.00 61.50 4.39 12.34 3.26 3.82 7.24 5.94 1.51 0.00 63.69 4.34 12.78 1.23 1.07 2.50 13.48 0.91 0.00 61.80 3.73 12.44 3.74 3.29 7.47 6.01 1.51 0.00 63.71 4.88 12.45 1.02 1.07 2.63 13.49 0.75 0.00 62.04 4.20 12.16 3.09 3.31 7.90 6.04 1.26 0.00 63.20 4.54 13.11 1.11 1.18 2.53 13.36 0.96 0.00 61.23 3.90 12.75 3.37 3.63 7.56 5.95 1.60 0.00 63.38 5.18 12.81 1.07 1.24 2.43 13.03 0.86 0.00 61.51 4.45 12.47 3.25 3.81 7.27 5.81 1.44 0.00 62.65 4.83 13.64 1.20 1.33 2.36 12.86 1.12 0.00 60.40 4.12 13.20 3.62 4.07 7.03 5.70 1.86 0.00 63.58 4.80 12.53 1.16 1.08 2.67 13.35 0.84 0.00 61.57 4.12 12.18 3.50 3.32 7.97 5.94 1.39 0.00 63.50 4.21 12.97 1.21 1.11 2.59 13.49 0.90 0.00 61.47 3.60 12.59 3.68 3.40 7.74 6.01 1.50 0.00 63.24 5.25 13.20 1.28 1.56 2.16 12.48 0.82 0.00 60.87 4.48 12.75 3.85 4.77 6.40 5.52 1.37 0.00 62.19 4.95 14.44 1.77 2.46 1.68 11.52 0.99 0.00 58.36 4.11 13.60 5.18 7.31 4.86 5.08 1.60 0.00 62.22 5.40 14.43 1.81 3.15 1.34 10.76 0.90 0.00 57.74 4.45 13.44 5.26 9.26 3.84 4.59 1.44 0.00 Average 61.50 5.12 15.24 1.90 3.21 1.25 10.68 1.10 0.00 56.88 4.19 14.15 5.52 9.41 3.55 4.54 1.76 0.00

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180Table C-17: Average EMPA data for LMSX-17. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Ru Hf Ni Cr Co W Re Ta Al Ru Hf 60.65 5.06 14.73 2.02 3.34 1.31 10.76 2.14 0.00 55.41 4.10 13.50 5.77 9.66 3.68 4.52 3.36 0.00 60.70 5.20 14.85 1.98 3.40 1.22 10.44 2.22 0.00 55.39 4.20 13.60 5.66 9.85 3.43 4.38 3.49 0.00 60.54 5.19 14.95 1.91 3.16 1.33 10.74 2.17 0.00 55.57 4.22 13.77 5.50 9.20 3.77 4.53 3.42 0.00 61.38 5.07 14.18 1.69 2.33 1.68 11.58 2.10 0.00 57.49 4.19 13.29 4.93 6.86 4.87 5.00 3.37 0.00 62.48 4.49 13.15 1.44 1.74 2.20 12.61 1.88 0.00 59.27 3.76 12.48 4.26 5.16 6.48 5.51 3.07 0.00 61.70 5.07 13.68 1.44 1.78 2.12 12.06 2.14 0.00 58.33 4.25 12.97 4.25 5.27 6.21 5.25 3.48 0.00 60.80 5.80 14.48 1.45 1.91 1.92 11.47 2.17 0.00 57.39 4.85 13.70 4.27 5.69 5.59 4.98 3.53 0.00 62.40 4.93 12.88 1.46 1.53 2.23 12.56 2.03 0.00 59.32 4.15 12.28 4.32 4.57 6.39 5.49 3.31 0.00 62.81 4.46 12.83 1.35 1.30 2.37 12.97 1.91 0.00 60.10 3.78 12.31 4.02 3.94 7.00 5.70 3.14 0.00 62.32 4.79 12.89 1.31 1.21 2.40 13.18 1.90 0.00 59.82 4.06 12.41 3.94 3.68 7.12 5.82 3.15 0.00 62.51 4.70 12.84 1.20 1.08 2.54 13.23 1.91 0.00 60.16 4.00 12.40 3.60 3.28 7.54 5.85 3.17 0.00 63.15 4.30 12.13 1.15 0.87 2.86 13.52 2.01 0.00 60.72 3.66 11.70 3.47 2.65 8.50 5.97 3.33 0.00 63.59 4.04 11.86 1.07 0.69 3.06 13.80 1.89 0.00 61.35 3.45 11.48 3.24 2.12 9.09 6.12 3.14 0.00 62.51 4.51 12.45 1.08 0.80 2.96 13.60 2.09 0.00 60.17 3.84 12.02 3.25 2.45 8.78 6.01 3.46 0.00 63.65 3.75 11.31 1.03 0.51 3.40 14.47 1.89 0.00 61.49 3.21 10.97 3.10 1.55 10.11 6.42 3.14 0.00 63.51 3.76 11.51 1.02 0.55 3.41 14.30 1.94 0.00 61.22 3.21 11.14 3.07 1.68 10.13 6.34 3.21 0.00 63.10 4.31 12.03 1.06 0.78 3.00 13.84 1.87 0.00 60.90 3.68 11.65 3.21 2.38 8.93 6.14 3.11 0.00 63.15 4.25 11.95 1.15 0.78 2.86 13.84 2.01 0.00 60.94 3.63 11.57 3.49 2.39 8.50 6.14 3.33 0.00 61.66 5.23 13.44 1.19 1.21 2.46 12.84 2.06 0.00 59.13 4.45 12.85 3.57 3.68 7.26 5.66 3.40 0.00 63.81 3.96 11.57 1.21 0.71 2.81 14.23 1.70 0.00 61.90 3.40 11.27 3.66 2.19 8.40 6.35 2.83 0.00 63.20 4.30 12.36 1.15 0.84 2.70 13.55 1.89 0.00 61.06 3.68 11.98 3.49 2.57 8.05 6.02 3.15 0.00 63.11 4.33 12.28 1.24 0.93 2.56 13.65 1.90 0.00 60.96 3.70 11.90 3.76 2.84 7.63 6.06 3.16 0.00 62.65 4.64 12.71 1.27 1.14 2.40 13.12 2.01 0.00 60.22 3.95 12.33 3.82 3.47 7.10 5.79 3.32 0.00 62.00 5.25 13.37 1.30 1.38 2.20 12.39 2.12 0.00 59.28 4.44 12.83 3.89 4.17 6.47 5.45 3.48 0.00 62.01 5.00 13.29 1.33 1.43 2.16 12.78 1.99 0.00 59.39 4.23 12.76 3.98 4.32 6.39 5.63 3.28 0.00 62.01 5.00 13.51 1.43 1.66 2.09 12.26 2.04 0.00 58.87 4.21 12.87 4.24 4.99 6.14 5.35 3.33 0.00 61.14 5.48 14.46 1.64 2.33 1.62 11.14 2.20 0.00 57.20 4.55 13.58 4.79 6.88 4.67 4.79 3.55 0.00 61.34 5.05 13.92 1.92 2.75 1.53 11.26 2.24 0.00 56.67 4.13 12.91 5.54 8.04 4.37 4.78 3.57 0.00 60.40 5.24 14.90 1.91 3.33 1.31 10.63 2.27 0.00 55.22 4.24 13.67 5.47 9.65 3.69 4.47 3.58 0.00 Average 60.27 5.25 14.99 2.02 3.47 1.25 10.45 2.29 0.00 54.83 4.24 13.69 5.77 10.00 3.52 4.37 3.59 0.00

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181Table C-18: Average EMPA data for LMSX-18. Atomic percent (at%) Normalized Weight percent (wt%) Ni Cr Co W Re Ta Al Pd Hf Ni Cr Co W Re Ta Al Pd Hf 62.40 5.09 15.05 2.11 3.48 1.32 10.25 0.31 0.00 57.26 4.13 13.86 6.06 10.12 3.74 4.33 0.51 0.00 61.84 5.32 15.13 2.06 3.37 1.34 10.45 0.48 0.00 56.89 4.33 13.97 5.94 9.84 3.82 4.42 0.81 0.00 62.62 5.04 14.50 1.80 2.74 1.64 11.04 0.61 0.00 58.43 4.17 13.58 5.25 8.08 4.71 4.74 1.04 0.00 63.35 4.71 13.50 1.41 1.64 2.17 12.25 0.98 0.00 60.50 3.97 12.91 4.19 4.93 6.40 5.38 1.71 0.00 64.38 3.84 11.75 1.06 0.71 2.70 14.10 1.47 0.00 62.75 3.31 11.49 3.23 2.18 8.12 6.32 2.59 0.00 64.01 3.85 11.55 0.96 0.64 2.83 14.41 1.75 0.00 62.41 3.32 11.30 2.92 1.98 8.53 6.46 3.09 0.00 62.32 5.27 13.41 1.12 1.18 2.36 12.86 1.47 0.00 60.18 4.50 13.00 3.48 3.62 7.02 5.71 2.58 0.00 63.90 4.08 11.71 1.09 0.74 2.81 14.07 1.61 0.00 62.00 3.51 11.40 3.31 2.27 8.41 6.27 2.83 0.00 64.65 3.26 10.91 1.00 0.52 3.04 14.87 1.74 0.00 62.99 2.81 10.67 3.04 1.62 9.14 6.66 3.07 0.00 62.60 4.78 12.57 1.12 1.07 2.52 13.59 1.75 0.00 60.48 4.09 12.19 3.37 3.29 7.50 6.03 3.05 0.00 62.00 5.32 13.38 1.22 1.28 2.26 13.03 1.50 0.00 59.80 4.54 12.94 3.67 3.92 6.74 5.78 2.62 0.00 63.75 4.08 11.69 1.11 0.80 2.80 14.08 1.69 0.00 61.75 3.49 11.35 3.36 2.43 8.38 6.27 2.97 0.00 62.77 4.96 12.63 1.06 1.06 2.43 13.46 1.64 0.00 60.85 4.25 12.28 3.22 3.25 7.27 5.99 2.88 0.00 63.62 4.01 11.56 0.96 0.73 2.92 14.29 1.92 0.00 61.69 3.44 11.25 2.91 2.23 8.74 6.37 3.37 0.00 62.19 5.37 13.06 1.08 1.16 2.42 13.01 1.71 0.00 60.00 4.59 12.65 3.27 3.55 7.18 5.77 3.00 0.00 62.42 5.22 12.55 1.08 1.01 2.50 13.54 1.68 0.00 60.48 4.47 12.20 3.28 3.11 7.47 6.03 2.95 0.00 63.50 4.30 11.48 1.00 0.72 2.80 14.46 1.74 0.00 61.84 3.71 11.22 3.05 2.23 8.41 6.47 3.08 0.00 64.11 3.40 10.94 0.98 0.45 3.06 15.13 1.93 0.00 62.55 2.94 10.71 3.00 1.41 9.21 6.78 3.41 0.00 63.16 4.59 12.26 1.05 0.93 2.65 13.79 1.57 0.00 61.27 3.95 11.94 3.19 2.85 7.92 6.15 2.76 0.00 63.92 3.61 11.49 1.06 0.70 2.97 14.81 1.44 0.00 62.20 3.11 11.23 3.21 2.17 8.91 6.62 2.55 0.00 64.57 3.53 11.15 0.95 0.52 3.04 14.65 1.58 0.00 63.00 3.05 10.93 2.90 1.62 9.14 6.57 2.79 0.00 64.30 3.67 11.15 0.98 0.54 3.04 14.76 1.55 0.00 62.72 3.17 10.91 2.99 1.74 9.13 6.62 2.73 0.00 64.09 4.02 11.62 1.03 0.71 2.80 14.15 1.57 0.00 62.36 3.46 11.34 3.15 2.19 8.39 6.33 2.77 0.00 62.94 4.72 12.34 1.03 0.86 2.70 14.03 1.39 0.00 61.28 4.07 12.05 3.13 2.64 8.10 6.28 2.45 0.00 64.52 3.90 11.50 0.98 0.63 2.89 14.10 1.47 0.00 62.86 3.37 11.25 2.99 1.94 8.68 6.31 2.60 0.00 66.88 3.58 12.13 1.03 0.87 2.25 11.95 1.23 0.08 64.86 3.08 11.81 3.11 2.66 6.75 5.34 2.17 0.23 63.81 4.16 12.45 1.28 1.15 2.30 13.44 1.41 0.00 61.67 3.56 12.07 3.88 3.52 6.85 5.97 2.48 0.00 62.87 5.12 14.28 1.76 2.46 1.59 11.18 0.74 0.00 59.07 4.26 13.47 5.18 7.34 4.60 4.83 1.26 0.00 61.94 5.45 15.04 2.06 3.49 1.39 10.18 0.45 0.00 56.74 4.42 13.84 5.90 10.13 3.93 4.28 0.75 0.00 Average 62.31 5.06 14.86 2.04 3.44 1.36 10.45 0.48 0.00 57.23 4.12 13.71 5.86 10.03 3.84 4.41 0.80 0.00

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182 APPENDIX D SCHEIL ANALYSIS GRAPHS FOR LMSX-3 This appendix contains all the graphs de veloped from the scheil analysis of LMSX3 for both the Full and Short methods as well as the EMPA data used for the Full method.

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183 LMSX-3 Ni Scheil Comparison60.00 65.00 70.00 75.00 80.00 85.00 90.00 00.20.40.60.811.2 vol%wt% Ni Full Short Figure D-1: Scheil curves comparing full and short techniques for Ni in LMSX-3 LMSX-3 Cr Scheil Comparison0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.20.40.60.811.2 vol%wt% Cr Full Short Figure D-2: Scheil curves comparing full and short techniques for Cr in LMSX-3.

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184 LMSX-3 Co Scheil Analysis0.00 1.00 2.00 3.00 4.00 5.00 6.00 00.20.40.60.811.2 vol%wt% Co Full Short Figure D-3: Scheil curves for both full a nd short techniques for Co in LMSX-3. LMSX-3 W Scheil Analysis0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.20.40.60.811.2 vol%wt% W Full Short Figure D-4: Scheil curves for both full and short techniques for W in LMSX-3.

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185 LMSX-3 Re Scheil Analysis0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 00.20.40.60.811.2 vol%wt% Re Full Short Figure D-5: Scheil curves for both long and short techniques for Re in LMSX-3. LMSX-3 Ta Scheil Analysis0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 00.20.40.60.811.2 vol%wt% Ta Full Short Figure D-6: Scheil curves for both long and short techniques for Ta in LMSX-3.

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186 LMSX-3 Al Scheil Analysis0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.20.40.60.811.2 vol%wt% Al Full Short Figure D-7: Scheil curves for both full a nd short techniques for Al in LMSX-3

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187Table D-1: EMPA data fo r LMSX-3 scheil analysis Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 73.63 4.12 3.92 0.97 0.78 2.71 13.86 72.55 3.60 3.88 3.01 2.45 8.23 6.28 73.05 5.10 4.80 1.67 2.48 1.54 11.35 69.27 4.29 4.57 4.97 7.47 4.50 4.94 72.84 6.01 4.91 1.65 3.00 1.51 10.07 68.03 4.97 4.61 4.83 8.89 4.35 4.32 73.26 4.27 3.85 1.02 0.84 2.99 13.77 71.61 3.70 3.78 3.12 2.59 9.01 6.19 73.52 4.75 4.06 1.40 1.68 2.16 12.44 70.78 4.05 3.92 4.22 5.12 6.41 5.50 72.93 5.49 4.22 1.20 1.47 2.46 12.22 70.36 4.69 4.09 3.62 4.51 7.32 5.42 73.01 5.15 4.11 1.46 1.91 2.22 12.13 69.69 4.35 3.94 4.38 5.78 6.54 5.32 72.57 5.71 4.74 1.57 2.87 1.84 10.70 67.82 4.73 4.45 4.61 8.52 5.29 4.59 73.41 4.91 3.61 1.13 1.02 3.24 12.68 70.60 4.18 3.48 3.42 3.10 9.62 5.60 72.65 5.85 3.96 1.18 1.39 3.00 11.97 69.42 4.95 3.80 3.52 4.22 8.84 5.25 72.70 6.73 4.63 1.40 2.51 2.12 9.92 68.11 5.59 4.35 4.10 7.46 6.12 4.27 73.06 5.87 4.48 1.45 2.24 2.30 10.60 68.68 4.88 4.22 4.27 6.68 6.67 4.58 73.39 5.68 4.16 1.38 1.82 2.65 10.91 69.31 4.75 3.95 4.09 5.45 7.72 4.74 72.80 5.92 4.47 1.60 2.91 2.29 10.02 67.15 4.83 4.14 4.63 8.50 6.50 4.25 1 73.55 6.00 4.08 1.43 1.94 2.64 10.36 69.06 4.99 3.85 4.20 5.78 7.65 4.47 72.60 5.68 4.55 1.34 1.69 1.97 12.16 70.19 4.86 4.41 4.07 5.18 5.87 5.40 73.31 4.76 3.92 1.01 0.95 2.62 13.42 71.95 4.13 3.86 3.11 2.97 7.92 6.05 74.19 4.27 3.82 1.21 1.20 2.28 13.02 72.44 3.70 3.75 3.69 3.71 6.87 5.84 72.42 6.20 4.71 1.72 3.11 1.63 10.20 67.28 5.10 4.39 5.01 9.18 4.68 4.36 72.64 5.40 4.62 1.48 2.35 2.05 11.47 68.72 4.52 4.38 4.39 7.04 5.97 4.98 72.46 5.80 4.26 1.51 2.27 2.11 11.58 68.60 4.86 4.05 4.47 6.82 6.16 5.04 73.59 3.19 3.24 0.92 0.24 4.17 14.66 71.53 2.74 3.16 2.79 0.73 12.50 6.55 73.20 5.27 3.71 1.11 1.35 2.89 12.47 70.38 4.49 3.58 3.34 4.13 8.57 5.51 72.15 5.70 4.37 1.73 3.29 2.10 10.66 66.31 4.64 4.03 4.97 9.59 5.96 4.50 73.03 5.21 4.18 1.60 2.58 2.33 11.07 68.07 4.30 3.92 4.66 7.62 6.69 4.74 72.26 7.21 4.89 1.28 2.45 2.14 9.77 67.90 6.00 4.62 3.76 7.30 6.21 4.22 73.41 5.21 4.09 1.37 1.84 2.78 11.30 69.23 4.35 3.87 4.05 5.51 8.09 4.90 72.79 5.62 4.71 1.65 3.51 2.05 9.68 66.45 4.54 4.32 4.70 10.16 5.77 4.06 73.01 6.29 4.41 1.58 3.05 2.23 9.43 67.09 5.12 4.07 4.53 8.89 6.32 3.98 2 72.98 6.35 4.74 1.69 3.82 2.04 8.38 65.80 5.07 4.29 4.77 10.94 5.66 3.47

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188Table D-1 (cont.): EMPA data for LMSX-3 scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 72.88 4.14 4.14 0.93 0.87 2.73 14.32 71.91 3.60 4.10 2.90 2.71 8.29 6.50 74.41 2.72 4.82 1.74 2.18 1.81 12.31 70.69 2.29 4.60 5.17 6.57 5.31 5.38 72.46 6.26 3.77 1.57 2.08 2.06 11.81 68.98 5.28 3.60 4.67 6.27 6.04 5.17 72.68 5.32 4.83 1.64 2.57 1.76 11.20 68.49 4.44 4.57 4.85 7.69 5.12 4.85 72.46 5.35 5.18 1.79 3.21 1.61 10.41 67.14 4.39 4.81 5.20 9.42 4.59 4.43 73.28 5.12 4.89 1.47 2.45 1.86 10.93 69.23 4.29 4.63 4.36 7.33 5.41 4.74 72.60 5.80 4.61 1.31 2.27 2.09 11.31 68.93 4.88 4.40 3.90 6.84 6.13 4.94 75.18 3.37 3.36 1.37 1.48 2.60 12.63 72.05 2.86 3.2 4.12 4.49 7.68 5.56 72.30 5.96 3.82 1.46 2.19 2.44 11.83 68.27 4.99 3.62 4.32 6.56 7.11 5.13 73.85 4.85 4.17 1.11 1.50 2.80 11.71 70.60 4.11 4.00 3.33 4.54 8.26 5.15 73.17 4.69 3.97 1.43 1.50 3.05 12.20 69.33 3.94 3.77 4.24 4.52 8.89 5.31 72.53 5.74 4.54 1.79 3.44 2.09 9.87 66.13 4.63 4.15 5.12 9.94 5.88 4.13 71.08 7.38 5.11 1.38 2.16 2.30 10.58 67.12 6.17 4.84 4.08 6.48 6.71 4.59 72.66 6.49 4.37 1.51 3.24 2.08 9.63 66.88 5.29 4.05 4.34 9.45 5.91 4.08 3 74.08 4.58 4.37 1.64 3.48 2.32 9.54 67.22 3.68 3.98 4.65 10.01 6.48 3.98 78.86 4.29 4.41 0.91 0.70 1.78 9.05 77.47 3.74 4.35 2.79 2.19 5.38 4.10 73.35 5.17 4.79 1.76 2.67 1.41 10.89 69.16 4.32 4.53 5.20 7.98 4.10 4.70 73.96 5.00 4.45 1.38 1.90 1.70 11.60 71.26 4.27 4.30 4.18 5.82 5.04 5.14 73.27 4.78 4.31 1.16 1.27 2.23 12.97 71.59 4.14 4.23 3.56 3.93 6.73 5.82 72.81 5.24 4.36 1.23 1.23 2.25 12.89 71.09 4.53 4.27 3.76 3.80 6.76 5.78 73.18 4.39 3.99 0.97 0.79 2.64 14.04 72.30 3.84 3.96 3.01 2.47 8.04 6.37 74.15 3.30 3.61 0.91 0.68 2.81 14.54 73.39 2.90 3.59 2.83 2.12 8.57 6.61 73.75 4.57 4.39 1.60 2.49 1.60 11.60 69.99 3.84 4.18 4.76 7.50 4.67 5.06 72.97 4.69 4.84 1.89 2.90 1.50 11.21 68.27 3.89 4.54 5.55 8.60 4.33 4.82 73.19 5.44 4.56 1.51 2.05 1.75 11.51 70.04 4.61 4.38 4.52 6.21 5.17 5.06 73.04 5.26 4.68 1.62 2.43 1.57 11.41 69.40 4.42 4.46 4.81 7.34 4.59 4.98 73.68 4.78 4.28 1.36 1.49 1.92 12.49 71.62 4.11 4.17 4.15 4.60 5.77 5.58 72.93 5.37 4.35 1.20 1.30 2.19 12.66 71.16 4.64 4.26 3.66 4.01 6.58 5.68 73.22 5.40 4.85 1.76 2.88 1.51 10.38 68.47 4.47 4.55 5.15 8.54 4.35 4.46 4 73.64 3.92 4.00 0.93 0.84 2.71 13.96 72.57 3.42 3.96 2.88 2.63 8.22 6.32

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189Table D-1 (cont.): EMPA data for LMSX-3 scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 79.00 4.21 4.09 0.64 0.42 2.20 9.44 77.99 3.70 4.10 2.00 1.33 6.69 4.30 73.05 5.32 4.32 1.19 1.30 2.29 12.54 71.11 4.54 4.22 3.62 4.00 6.86 5.61 72.92 5.25 4.74 1.29 1.98 1.89 11.94 70.15 4.47 4.57 3.87 6.04 5.61 5.28 73.62 4.81 5.05 1.53 2.26 1.60 11.13 70.14 4.06 4.83 4.57 6.84 4.70 4.87 73.38 4.98 4.66 1.79 2.64 1.45 11.09 69.22 4.16 4.42 5.29 7.90 4.20 4.81 73.83 4.65 3.97 1.08 1.11 2.33 13.03 72.39 4.04 3.90 3.30 3.46 7.03 5.87 72.45 6.02 4.42 1.26 1.42 2.13 12.30 70.43 5.18 4.31 3.84 4.37 6.38 5.49 73.69 5.20 4.70 1.69 2.56 1.45 10.71 69.64 4.36 4.50 5.01 7.67 4.22 4.65 73.13 5.16 4.57 1.52 2.10 1.67 11.83 70.10 4.38 4.41 4.56 6.39 4.95 5.21 75.06 4.72 4.65 1.65 0.00 1.71 12.20 75.09 4.18 4.67 5.17 0.00 5.27 5.61 73.22 5.88 4.42 1.07 1.54 2.02 11.86 71.25 5.06 4.32 3.27 4.74 6.06 5.30 73.80 4.88 3.96 1.01 0.92 2.54 12.89 72.40 4.24 3.90 3.11 2.87 7.67 5.81 72.76 7.08 4.60 1.37 1.93 1.70 10.56 69.85 6.02 4.43 4.12 5.89 5.03 4.66 73.56 5.41 4.73 1.33 1.71 1.73 11.52 71.19 4.64 4.59 4.04 5.25 5.17 5.12 5 73.07 5.35 4.93 1.71 2.78 1.45 10.72 68.74 4.46 4.65 5.03 8.29 4.20 4.63 78.48 4.74 4.60 1.15 0.88 1.50 8.66 76.73 4.10 4.51 3.52 2.73 4.51 3.90 72.57 4.75 4.36 1.50 1.86 1.86 13.09 70.11 4.07 4.23 4.55 5.70 5.53 5.81 72.63 6.35 5.22 1.08 1.72 1.82 11.18 70.47 5.46 5.08 3.28 5.28 5.45 4.98 73.98 4.30 3.99 1.21 1.10 2.22 13.21 72.54 3.73 3.93 3.71 3.42 6.71 5.95 72.98 4.82 4.59 1.69 2.29 1.54 12.09 69.69 4.07 4.40 5.06 6.95 4.52 5.30 73.01 4.82 3.95 1.06 0.73 2.60 13.83 72.12 4.22 3.91 3.27 2.28 7.91 6.28 73.11 4.99 4.67 1.46 1.74 1.72 12.30 70.79 4.28 4.54 4.43 5.35 5.13 5.48 73.13 5.02 4.60 1.43 1.69 1.82 12.32 70.82 4.30 4.47 4.32 5.18 5.42 5.48 70.70 7.87 5.10 1.17 1.65 2.06 11.45 68.44 6.75 4.95 3.56 5.06 6.15 5.09 73.56 3.98 3.89 1.27 1.14 2.25 13.91 72.18 3.46 3.83 3.89 3.56 6.81 6.27 73.56 4.69 4.50 1.60 2.13 1.73 11.78 70.22 3.97 4.31 4.78 6.45 5.10 5.17 72.90 4.80 4.57 1.92 2.51 1.52 11.78 68.89 4.01 4.34 5.69 7.53 4.42 5.12 73.04 6.30 5.61 1.80 2.99 1.09 9.17 68.29 5.21 5.26 5.28 8.86 3.15 3.94 72.19 6.19 5.61 1.89 3.50 1.09 9.55 66.81 5.07 5.21 5.46 10.26 3.12 4.06 6 73.29 5.09 4.53 1.67 2.60 1.59 11.23 69.21 4.26 4.29 4.95 7.80 4.62 4.87

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190Table D-1 (cont.): EMPA data for LMSX-3 scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.21 4.22 4.61 1.21 1.00 1.49 9.25 76.38 3.70 4.50 3.70 3.11 4.48 4.20 73.56 4.80 4.00 1.16 1.37 2.21 12.90 71.73 4.14 3.91 3.55 4.23 6.65 5.78 74.53 3.94 3.83 1.27 1.10 2.24 13.10 72.90 3.41 3.76 3.88 3.40 6.75 5.89 73.66 3.09 3.35 1.04 0.39 2.94 15.53 73.34 2.73 3.35 3.23 1.22 9.02 7.11 73.35 4.29 4.17 1.61 2.17 1.87 12.54 70.00 3.62 3.99 4.81 6.57 5.50 5.50 73.56 4.13 3.97 1.54 1.49 2.06 13.24 71.27 3.55 3.86 4.68 4.59 6.16 5.90 72.61 4.91 4.65 1.86 2.94 1.42 11.63 68.20 4.08 4.38 5.46 8.75 4.11 5.02 72.18 5.94 4.40 1.17 1.41 2.27 12.63 70.20 5.12 4.3 3.56 4.36 6.82 5.65 72.72 5.26 4.03 1.08 0.98 2.50 13.43 71.44 4.58 3.98 3.31 3.05 7.57 6.07 73.52 4.58 3.87 1.23 1.04 2.41 13.35 71.96 3.97 3.81 3.77 3.22 7.28 6.00 74.04 3.79 3.86 1.53 1.53 1.94 13.31 71.87 3.26 3.76 4.66 4.70 5.81 5.94 73.66 2.78 3.27 0.77 0.07 3.58 15.87 73.40 2.45 3.27 2.42 0.21 10.99 7.27 73.37 4.51 4.25 1.66 2.00 1.78 12.44 70.32 3.83 4.08 4.97 6.06 5.26 5.48 72.01 5.85 4.88 1.53 2.45 1.78 11.50 68.29 4.91 4.65 4.55 7.38 5.21 5.01 7 73.87 4.29 4.21 1.44 1.51 1.88 12.80 71.83 3.69 4.11 4.37 4.64 5.63 5.72 78.60 4.47 5.18 1.20 1.38 1.27 7.89 75.98 3.83 5.03 3.65 4.23 3.78 3.5 77.14 4.99 5.01 1.65 2.05 1.09 8.07 73.23 4.20 4.77 4.90 6.18 3.19 3.52 77.55 3.95 4.30 0.86 0.48 2.12 10.73 76.73 3.46 4.27 2.68 1.52 6.47 4.88 76.94 4.54 4.37 1.47 1.13 1.42 10.13 75.02 3.92 4.27 4.49 3.48 4.28 4.54 76.50 4.33 4.71 1.45 1.12 1.38 10.51 74.84 3.75 4.62 4.43 3.47 4.16 4.73 75.04 5.44 4.97 1.87 2.01 1.09 9.59 71.57 4.59 4.75 5.60 6.07 3.21 4.20 74.02 6.25 5.07 1.32 1.18 1.50 10.63 72.56 5.43 4.98 4.05 3.67 4.52 4.79 73.94 5.88 5.46 1.68 1.98 1.22 9.85 70.81 4.99 5.25 5.03 6.00 3.59 4.33 74.32 4.37 4.23 1.41 0.95 1.91 12.81 73.12 3.80 4.18 4.35 2.97 5.79 5.79 73.26 5.55 4.60 1.17 1.11 1.82 12.49 72.30 4.85 4.56 3.61 3.46 5.55 5.66 72.71 6.85 5.73 1.34 2.07 1.26 10.04 70.04 5.84 5.54 4.06 6.33 3.75 4.44 71.79 6.83 6.05 2.09 3.63 0.89 8.72 66.01 5.56 5.58 6.03 10.59 2.53 3.68 73.35 4.99 4.98 1.83 2.75 1.33 10.78 69.02 4.16 4.70 5.40 8.21 3.84 4.66 72.90 4.87 4.87 1.91 2.80 1.41 11.24 68.48 4.05 4.60 5.61 8.34 4.07 4.85 8 72.45 6.11 4.77 1.45 1.89 1.76 11.57 69.71 5.21 4.60 4.36 5.78 5.22 5.12

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191Table D-1 (cont.): EMPA data for LMSX-3 scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co Pass Ni Cr Co Pass Ni Cr Co Pass Ni Cr Co 78.49 4.40 4.50 9 78.49 4.40 4.50 9 78.49 4.40 4.50 9 78.49 4.40 4.50 73.90 4.06 4.22 73.90 4.06 4.22 73.90 4.06 4.22 73.90 4.06 4.22 73.96 3.97 4.05 73.96 3.97 4.05 73.96 3.97 4.05 73.96 3.97 4.05 73.20 5.42 4.55 73.20 5.42 4.55 73.20 5.42 4.55 73.20 5.42 4.55 73.62 4.10 3.99 73.62 4.10 3.99 73.62 4.10 3.99 73.62 4.10 3.99 73.65 4.06 4.01 73.65 4.06 4.01 73.65 4.06 4.01 73.65 4.06 4.01 73.67 4.23 3.79 73.67 4.23 3.79 73.67 4.23 3.79 73.67 4.23 3.79 73.42 5.22 4.51 73.42 5.22 4.51 73.42 5.22 4.51 73.42 5.22 4.51 72.07 6.10 4.36 72.07 6.10 4.36 72.07 6.10 4.36 72.07 6.10 4.36 73.65 4.98 4.21 73.65 4.98 4.21 73.65 4.98 4.21 73.65 4.98 4.21 73.70 4.05 3.69 73.70 4.05 3.69 73.70 4.05 3.69 73.70 4.05 3.69 73.20 4.40 4.21 73.20 4.40 4.21 73.20 4.40 4.21 73.20 4.40 4.21 74.17 2.36 3.09 74.17 2.36 3.09 74.17 2.36 3.09 74.17 2.36 3.09 73.54 3.93 3.78 73.54 3.93 3.78 73.54 3.93 3.78 73.54 3.93 3.78 9 72.95 5.86 4.68 72.95 5.86 4.68 72.95 5.86 4.68 72.95 5.86 4.68 78.99 4.98 5.20 10 78.99 4.98 5.20 10 78.99 4.98 5.20 10 78.99 4.98 5.20 73.03 5.17 4.15 73.03 5.17 4.15 73.03 5.17 4.15 73.03 5.17 4.15 73.00 4.24 4.11 73.00 4.24 4.11 73.00 4.24 4.11 73.00 4.24 4.11 72.44 5.69 4.71 72.44 5.69 4.71 72.44 5.69 4.71 72.44 5.69 4.71 73.27 4.13 3.75 73.27 4.13 3.75 73.27 4.13 3.75 73.27 4.13 3.75 72.87 4.52 3.89 72.87 4.52 3.89 72.87 4.52 3.89 72.87 4.52 3.89 73.28 4.68 4.15 73.28 4.68 4.15 73.28 4.68 4.15 73.28 4.68 4.15 72.74 5.36 4.61 72.74 5.36 4.61 72.74 5.36 4.61 72.74 5.36 4.61 72.80 4.99 4.48 72.80 4.99 4.48 72.80 4.99 4.48 72.80 4.99 4.48 71.89 6.16 4.65 71.89 6.16 4.65 71.89 6.16 4.65 71.89 6.16 4.65 73.33 4.21 4.34 73.33 4.21 4.34 73.33 4.21 4.34 73.33 4.21 4.34 72.84 5.08 4.66 72.84 5.08 4.66 72.84 5.08 4.66 72.84 5.08 4.66 72.31 4.72 3.91 72.31 4.72 3.91 72.31 4.72 3.91 72.31 4.72 3.91 72.81 5.82 4.62 72.81 5.82 4.62 72.81 5.82 4.62 72.81 5.82 4.62 10 73.64 4.29 3.84 73.64 4.29 3.84 73.64 4.29 3.84 73.64 4.29 3.84

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192Table D-1 (cont.): EMPA data for LMSX-3 scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.56 4.15 4.14 0.90 0.46 2.08 9.70 77.37 3.6 4.1 2.8 1.44 6.32 4.4 72.64 6.00 5.40 1.79 3.67 1.17 9.33 66.94 4.90 5.00 5.18 10.72 3.32 3.95 72.67 5.00 4.31 1.30 1.57 2.05 13.10 70.69 4.31 4.21 3.96 4.83 6.14 5.86 72.22 6.02 4.59 1.10 1.38 2.17 12.53 70.52 5.21 4.50 3.36 4.27 6.53 5.62 73.34 5.45 4.83 1.62 2.79 1.34 10.63 69.21 4.55 4.58 4.78 8.36 3.91 4.61 73.94 3.33 3.83 1.13 0.70 2.62 14.46 73.06 2.91 3.80 3.51 2.18 7.98 6.57 72.68 4.83 4.29 1.71 2.25 1.78 12.46 69.25 4.08 4.10 5.10 6.79 5.21 5.46 71.45 6.69 4.80 1.16 1.51 2.12 12.28 69.52 5.76 4.7 3.55 4.65 6.36 5.49 73.34 4.29 3.71 1.17 0.76 2.53 14.20 72.44 3.75 3.68 3.62 2.37 7.69 6.45 73.37 4.62 4.42 1.30 1.56 2.03 12.69 71.23 3.97 4.31 3.95 4.81 6.06 5.66 72.77 5.07 4.21 1.46 1.65 1.95 12.88 70.48 4.35 4.09 4.43 5.08 5.83 5.73 73.05 5.23 4.88 1.67 2.55 1.43 11.18 69.27 4.40 4.65 4.97 7.66 4.18 4.87 70.00 8.60 5.48 1.03 2.11 1.89 10.89 67.39 7.33 5.29 3.10 6.45 5.61 4.82 72.69 4.93 4.76 1.66 2.23 1.63 12.11 69.45 4.17 4.56 4.98 6.74 4.79 5.32 11 74.13 3.62 3.77 1.38 1.15 2.16 13.78 72.60 3.14 3.71 4.25 3.57 6.53 6.20 77.96 4.44 4.97 1.43 1.25 1.36 8.59 75.36 3.80 4.82 4.33 3.82 4.05 3.8 73.23 4.80 4.39 1.49 1.89 1.70 12.49 70.72 4.10 4.26 4.50 5.80 5.07 5.54 73.03 4.75 4.45 1.78 2.62 1.60 11.76 68.93 3.97 4.22 5.26 7.86 4.66 5.10 72.38 6.00 5.26 1.87 3.46 1.25 9.77 66.92 4.91 4.88 5.41 10.14 3.57 4.15 73.48 5.21 4.72 1.55 2.11 1.60 11.33 70.30 4.41 4.53 4.65 6.40 4.72 4.98 73.23 4.95 4.12 0.97 0.80 2.54 13.40 72.29 4.33 4.08 2.99 2.51 7.71 6.08 72.66 5.40 4.89 1.71 2.66 1.59 11.08 68.44 4.51 4.62 5.05 7.95 4.63 4.80 72.36 5.75 4.82 1.58 2.10 1.55 11.84 69.50 4.89 4.64 4.76 6.39 4.59 5.23 72.55 6.54 4.95 1.23 1.93 1.78 11.01 69.86 5.58 4.79 3.71 5.90 5.30 4.87 73.38 5.90 4.98 1.28 2.12 1.53 10.81 70.55 5.02 4.81 3.85 6.47 4.52 4.78 72.96 4.56 4.25 1.24 1.20 2.11 13.68 71.70 3.97 4.19 3.82 3.75 6.39 6.18 73.00 4.63 4.61 1.86 2.77 1.54 11.60 68.61 3.85 4.35 5.46 8.26 4.45 5.01 72.29 6.65 5.04 1.29 2.02 1.83 10.87 69.30 5.65 4.85 3.87 6.14 5.41 4.79 72.31 5.89 4.39 1.26 1.50 2.11 12.54 70.26 5.07 4.28 3.84 4.63 6.32 5.60 12 72.66 5.23 4.86 1.85 2.86 1.43 11.11 68.20 4.35 4.58 5.43 8.52 4.13 4.79

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193Table D-1 (cont.): EMPA data for LMSX-3 scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.72 5.08 4.50 0.95 0.94 1.42 8.38 77.22 4.4 4.4 2.9 2.92 4.3 3.8 73.91 4.65 4.08 1.38 1.68 1.99 12.31 71.36 3.97 3.95 4.18 5.15 5.92 5.46 72.98 5.48 4.81 1.43 2.43 1.74 11.12 69.28 4.61 4.58 4.26 7.32 5.09 4.85 73.08 5.03 4.71 1.67 3.09 1.47 10.95 68.39 4.17 4.42 4.91 9.17 4.24 4.71 73.64 4.26 4.06 1.34 1.45 2.00 13.24 71.82 3.68 3.97 4.10 4.50 6.00 5.93 73.81 4.16 3.75 1.02 0.73 2.70 13.84 72.76 3.63 3.71 3.15 2.28 8.20 6.27 73.70 4.64 3.96 1.23 1.21 2.34 12.91 71.82 4.01 3.88 3.74 3.74 7.04 5.78 73.92 4.15 3.74 1.33 1.14 2.29 13.43 72.22 3.59 3.7 4.06 3.53 6.90 6.03 73.21 4.88 4.10 0.86 0.94 2.69 13.32 71.97 4.25 4.05 2.64 2.93 8.15 6.02 73.71 4.09 3.84 0.88 0.67 2.76 14.05 72.96 3.59 3.81 2.72 2.11 8.42 6.39 73.27 4.88 4.07 1.30 1.32 2.07 13.08 71.59 4.22 3.99 3.97 4.10 6.24 5.87 73.24 5.00 4.49 1.73 2.58 1.56 11.40 69.22 4.19 4.26 5.13 7.72 4.53 4.95 72.38 6.02 4.48 1.23 1.30 2.18 12.42 70.55 5.19 4.39 3.77 4.01 6.54 5.56 73.38 4.94 4.12 1.28 1.30 2.14 12.85 71.59 4.27 4.03 3.90 4.01 6.44 5.76 13 71.58 7.11 5.17 1.19 1.92 1.80 11.24 69.11 6.08 5.01 3.60 5.87 5.35 4.99 78.57 4.64 4.37 0.80 0.53 1.95 9.14 77.44 4.05 4.33 2.47 1.64 5.93 4.1 72.86 5.53 4.42 1.26 1.35 2.10 12.46 70.99 4.78 4.33 3.84 4.17 6.32 5.58 73.30 5.51 4.32 1.27 1.71 1.92 11.97 70.94 4.72 4.20 3.84 5.26 5.72 5.33 73.16 5.43 4.23 1.33 1.66 1.97 12.22 70.80 4.65 4.11 4.03 5.09 5.88 5.44 73.38 4.93 4.77 1.61 2.24 1.57 11.50 70.01 4.17 4.57 4.80 6.79 4.63 5.04 71.77 6.25 4.76 1.27 1.57 2.10 12.28 69.57 5.37 4.63 3.85 4.83 6.28 5.47 74.31 2.89 3.20 0.86 0.29 3.32 15.11 73.65 2.54 3.19 2.68 0.92 10.14 6.88 74.45 3.80 3.43 1.31 1.09 2.15 13.77 73.16 3.30 3.38 4.02 3.40 6.52 6.22 73.32 4.73 3.90 0.96 0.96 2.54 13.58 72.20 4.12 3.86 2.96 3.01 7.70 6.15 73.14 4.55 4.50 1.86 2.68 1.49 11.79 69.00 3.80 4.26 5.49 8.01 4.32 5.11 73.21 4.90 4.31 1.36 1.67 1.88 12.66 71.04 4.21 4.20 4.14 5.14 5.62 5.65 72.59 5.64 5.04 1.72 2.54 1.49 10.97 68.66 4.73 4.79 5.08 7.63 4.35 4.77 73.46 4.71 4.34 1.53 1.90 1.86 12.21 70.54 4.01 4.18 4.59 5.80 5.49 5.39 72.49 5.89 4.02 0.78 0.76 2.69 13.36 71.75 5.16 4.00 2.42 2.40 8.20 6.08 14 70.47 9.66 5.58 0.97 1.87 1.73 9.71 68.15 8.27 5.42 2.95 5.73 5.17 4.31

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194Table D-1 (cont): EMPA data for LMSX-3 scheil analysis Atomic Percent Weight Percent Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.11 4.50 4.28 1.04 0.50 1.80 9.76 77.12 3.93 4.24 3.23 1.57 5.48 4.43 73.26 4.88 4.03 0.91 1.05 2.74 13.13 71.62 4.23 3.95 2.80 3.25 8.25 5.90 71.20 7.88 5.40 1.30 2.37 1.63 10.23 67.88 6.65 5.16 3.87 7.16 4.79 4.48 72.96 5.46 4.50 1.15 1.39 2.13 12.41 71.11 4.71 4.40 3.51 4.30 6.41 5.56 72.49 6.34 5.31 1.81 3.25 1.19 9.60 67.44 5.23 4.96 5.26 9.59 3.42 4.10 72.83 5.37 4.83 1.61 2.41 1.49 11.46 69.37 4.53 4.62 4.80 7.29 4.37 5.02 74.16 3.03 3.29 0.91 0.46 2.98 15.16 73.70 2.67 3.28 2.84 1.44 9.14 6.92 74.03 3.77 3.81 1.27 1.04 2.25 13.84 72.76 3.28 3.76 3.91 3.23 6.81 6.25 73.33 5.21 4.67 1.75 2.70 1.39 10.95 69.19 4.35 4.42 5.18 8.08 4.03 4.75 72.66 4.68 4.52 1.84 2.69 1.57 12.05 68.54 3.91 4.28 5.42 8.05 4.58 5.22 73.81 3.93 3.93 1.50 1.68 1.84 13.30 71.62 3.38 3.83 4.55 5.17 5.51 5.93 72.97 5.01 4.67 1.68 2.21 1.57 11.88 69.70 4.24 4.48 5.04 6.69 4.63 5.22 73.02 5.03 4.27 1.72 2.40 1.70 11.85 69.24 4.23 4.07 5.10 7.22 4.97 5.17 74.06 2.57 3.24 0.73 0.10 3.49 15.81 73.91 2.27 3.25 2.28 0.32 10.72 7.25 15 74.10 2.69 3.26 0.96 0.23 3.36 15.40 73.42 2.36 3.25 2.99 0.72 10.26 7.01

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195 APPENDIX E SCHEIL ANALYSIS DATA AND GRAPHS FOR CMSX-4 This appendix contains the data and graphs that were used to evaluate the accuracy of the analysis used in this study on a co mmon commercial alloy whose properties have been widely examined.

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196 Scheil Analysis for Ni in CMSX-40.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Ni Ni Figure E-1: Scheil curv e for Ni from CMSX-4. Scheil Analysis for Cr in CMSX-40.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Cr Cr Figure E-2: Scheil curv e for Cr from CMSX-4.

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197 Scheil Analysis for Co in CMSX-40.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Co Co Figure E-3: Scheil curv e for Co from CMSX-4. Scheil Analysis for Mo in CMSX-40.00 0.50 1.00 1.50 2.00 2.50 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Mo Mo Figure E-4: Scheil curve for Mo from CMSX-4.

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198 Scheil Analysis for W in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% W W Figure E-5: Scheil curve for W in CMSX-4. Scheil Analysis for Re in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Re Re Figure E-6: Scheil curv e for Re in CMSX-4.

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199 Scheil Analysis for Ta in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Ta Ta Figure E-7: Scheil curv e for Ta from CMSX-4. Scheil Analysis for Al in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Al Al Figure E-8: Scheil curv e for Al from CMSX-4.

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200 Scheil Analysis for Ti in CMSX-40.00 0.50 1.00 1.50 2.00 2.50 3.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Ti Ti Figure E-9: Scheil curve for Ti from CMSX-4

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201 Table E-1: Scheil curve data for CMSX-4 Ni Cr Co Mo W Re Ta Al Ti 69.09 15.16 7.57 2.24 1.84 0.00 8.89 7.26 2.42 69.02 13.04 7.68 1.55 2.26 0.17 8.89 7.19 2.27 68.81 12.25 7.70 1.22 2.42 0.19 8.66 7.13 2.17 68.77 11.98 7.74 1.21 2.52 0.31 8.26 7.09 1.94 68.67 11.18 7.75 1.16 2.56 0.36 8.08 7.08 1.90 68.33 10.24 7.88 0.93 2.62 0.46 7.85 7.08 1.88 68.09 9.66 7.91 0.92 2.66 0.64 7.63 6.97 1.85 68.03 9.53 7.95 0.90 2.68 0.72 7.52 6.95 1.83 67.99 9.18 8.02 0.89 2.72 0.75 7.51 6.94 1.80 67.93 9.09 8.05 0.87 3.00 0.76 7.29 6.90 1.77 67.65 8.96 8.08 0.86 3.03 0.78 7.01 6.88 1.72 67.61 8.93 8.16 0.85 3.04 0.80 6.96 6.87 1.72 67.59 8.83 8.20 0.84 3.06 0.92 6.94 6.86 1.69 67.53 8.67 8.21 0.84 3.07 0.92 6.91 6.86 1.63 67.41 8.00 8.23 0.83 3.14 0.95 6.88 6.82 1.61 67.39 7.90 8.27 0.81 3.16 0.95 6.77 6.81 1.61 67.37 7.78 8.27 0.81 3.17 0.96 6.76 6.79 1.60 67.35 7.72 8.32 0.80 3.18 1.02 6.70 6.77 1.60 67.26 7.66 8.42 0.79 3.22 1.05 6.60 6.73 1.59 67.22 7.59 8.42 0.77 3.23 1.13 6.42 6.63 1.55 66.84 7.56 8.50 0.77 3.31 1.30 6.37 6.61 1.53 66.56 7.53 8.54 0.77 3.37 1.46 6.32 6.55 1.53 66.48 7.46 8.87 0.75 3.37 1.49 6.28 6.54 1.50 66.45 7.35 8.88 0.75 3.38 1.52 6.12 6.54 1.49 66.38 7.31 8.90 0.75 3.42 1.55 6.03 6.52 1.48 66.11 7.28 8.92 0.74 3.51 1.56 6.03 6.47 1.47 65.90 7.26 8.93 0.73 3.59 1.66 6.00 6.46 1.42 65.87 7.16 8.98 0.72 3.69 1.70 5.86 6.46 1.41 65.72 7.16 9.00 0.72 3.72 1.74 5.85 6.42 1.40 65.70 6.98 9.00 0.69 3.73 1.75 5.80 6.42 1.36 65.61 6.97 9.04 0.69 3.76 1.77 5.70 6.39 1.35 65.53 6.88 9.05 0.68 3.76 1.77 5.62 6.39 1.32 65.47 6.81 9.13 0.67 3.77 1.81 5.57 6.38 1.31 65.47 6.60 9.14 0.67 3.78 1.86 5.57 6.37 1.30 65.41 6.54 9.14 0.66 3.79 1.92 5.53 6.37 1.30 65.40 6.50 9.15 0.64 3.82 1.93 5.41 6.36 1.28 65.32 6.45 9.25 0.63 3.83 1.94 5.37 6.36 1.27 65.30 6.41 9.26 0.62 3.86 1.97 5.34 6.32 1.25 65.28 6.29 9.32 0.62 3.87 1.97 5.29 6.24 1.25 65.25 6.26 9.32 0.61 3.91 2.029 5.29 6.21 1.24 65.10 6.23 9.34 0.61 3.93 2.05 5.26 6.15 1.24 65.09 6.20 9.35 0.61 3.94 2.10 5.20 6.15 1.22 65.07 6.19 9.39 0.60 3.95 2.13 5.19 6.12 1.22

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202 Table E-1 (cont.): Scheil curve data for CMSX-4 Ni Cr Co Mo W Re Ta Al Ti 65.06 6.18 9.40 0.60 4.04 2.13 5.09 6.10 1.20 64.84 6.16 9.41 0.59 4.04 2.19 5.03 6.04 1.20 64.82 6.08 9.43 0.59 4.06 2.20 4.92 6.02 1.20 64.75 6.05 9.49 0.59 4.07 2.36 4.90 6.02 1.19 64.75 6.03 9.62 0.58 4.14 2.39 4.87 6.01 1.19 64.56 6.03 9.67 0.58 4.14 2.41 4.87 6.01 1.19 64.47 5.90 9.79 0.58 4.17 2.48 4.86 5.99 1.18 64.22 5.89 9.82 0.58 4.18 2.50 4.84 5.95 1.17 64.08 5.87 9.85 0.57 4.19 2.55 4.83 5.90 1.14 64.04 5.79 9.90 0.57 4.21 2.57 4.81 5.85 1.13 63.66 5.71 9.91 0.56 4.21 2.63 4.79 5.81 1.13 63.61 5.70 9.96 0.55 4.22 2.64 4.69 5.78 1.12 63.55 5.66 10.03 0.55 4.23 2.72 4.59 5.76 1.11 63.55 5.64 10.08 0.54 4.24 2.73 4.57 5.74 1.09 63.54 5.53 10.08 0.54 4.26 2.74 4.56 5.73 1.09 63.39 5.44 10.09 0.54 4.27 2.83 4.51 5.72 1.08 63.35 5.42 10.13 0.54 4.32 2.83 4.49 5.72 1.08 63.33 5.41 10.13 0.54 4.33 2.93 4.48 5.72 1.06 63.26 5.41 10.15 0.54 4.36 2.94 4.36 5.70 1.06 63.04 5.38 10.18 0.54 4.39 2.98 4.24 5.63 1.02 62.84 5.30 10.19 0.53 4.48 3.05 4.20 5.59 1.00 62.63 5.29 10.20 0.53 4.49 3.16 4.19 5.46 0.96 62.58 5.27 10.31 0.52 4.57 3.32 4.05 5.45 0.96 62.50 5.22 10.56 0.51 4.57 3.33 3.87 5.43 0.95 62.18 5.15 10.59 0.50 4.64 3.44 3.85 5.40 0.95 62.06 5.11 10.59 0.50 4.70 3.54 3.85 5.37 0.94 61.83 5.08 10.62 0.48 4.75 3.60 3.77 5.30 0.93 61.77 4.62 10.73 0.48 4.83 3.71 3.73 5.09 0.88 61.69 4.60 10.76 0.48 4.89 3.71 3.66 5.06 0.87 61.68 4.58 10.90 0.48 4.90 3.72 3.65 5.01 0.86 61.64 4.44 10.95 0.47 4.90 3.80 3.52 4.98 0.85 61.62 4.40 11.10 0.46 5.20 3.95 3.51 4.96 0.82 61.62 4.38 11.10 0.46 5.21 4.00 3.45 4.96 0.80 61.45 4.30 11.19 0.45 5.32 4.02 3.43 4.92 0.79 61.42 4.26 11.22 0.44 5.69 4.20 3.38 4.90 0.71 61.20 4.17 11.27 0.44 5.89 4.41 3.17 4.87 0.70 61.07 4.04 11.31 0.43 5.96 4.43 3.01 4.87 0.69 60.48 4.01 11.54 0.41 6.19 4.69 2.98 4.83 0.66 60.43 3.86 11.56 0.41 6.19 4.89 2.93 4.83 0.64 60.40 3.80 11.56 0.39 6.26 4.91 2.93 4.82 0.63 59.89 3.49 11.64 0.37 6.35 5.05 2.89 4.81 0.62 58.91 3.39 11.67 0.30 6.48 5.10 2.88 4.73 0.62

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203 Table E-1 (cont.): Scheil curve data for CMSX-4 Ni Cr Co Mo W Re Ta Al Ti 58.18 3.16 11.78 0.30 6.50 5.15 2.84 4.63 0.61 57.94 3.11 12.32 0.27 6.53 5.22 2.80 4.60 0.61 56.63 3.09 12.36 0.25 6.55 5.36 2.66 4.04 0.58 56.42 3.03 12.47 0.25 6.56 5.41 2.34 3.97 0.54 54.26 2.88 13.19 0.21 6.57 5.77 1.97 3.91 0.51

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204 APPENDIX F SCHEIL ANALYSIS GRAPHS FOR LMSX-3 This appendix contains all the graphs de veloped from the scheil analysis of LMSX3 for both the Full and Short methods as well as the EMPA data used for the Full method.

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205 LMSX-3 Ni Scheil Comparison60.00 65.00 70.00 75.00 80.00 85.00 90.00 00.20.40.60.811.2 vol%wt% Ni Full Short Figure F-1: Scheil curves comparing full and short techniques for Ni in LMSX-3 LMSX-3 Cr Scheil Comparison0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.20.40.60.811.2 vol%wt% Cr Full Short Figure F-2: Scheil curves comparing full and short techniques for Cr in LMSX-3.

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206 LMSX-3 Co Scheil Analysis0.00 1.00 2.00 3.00 4.00 5.00 6.00 00.20.40.60.811.2 vol%wt% Co Full Short Figure F-3: Scheil curves for both full and short techniques for Co in LMSX-3. LMSX-3 W Scheil Analysis0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.20.40.60.811.2 vol%wt% W Full Short Figure F-4: Scheil curves for both full and short techniques for W in LMSX-3.

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207 LMSX-3 Re Scheil Analysis0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 00.20.40.60.811.2 vol%wt% Re Full Short Figure F-5: Scheil curves for both long a nd short techniques for Re in LMSX-3. LMSX-3 Ta Scheil Analysis0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 00.20.40.60.811.2 vol%wt% Ta Full Short Figure F-6: Scheil curves for both long a nd short techniques for Ta in LMSX-3.

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208 LMSX-3 Al Scheil Analysis0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 00.20.40.60.811.2 vol%wt% Al Full Short Figure F-7: Scheil curves for both full and short techniques for Al in LMSX-3

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209Table F-1: EMPA data for LMSX-3 Scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 73.63 4.12 3.92 0.97 0.78 2.71 13.86 72.55 3.60 3.88 3.01 2.45 8.23 6.28 73.05 5.10 4.80 1.67 2.48 1.54 11.35 69.27 4.29 4.57 4.97 7.47 4.50 4.94 72.84 6.01 4.91 1.65 3.00 1.51 10.07 68.03 4.97 4.61 4.83 8.89 4.35 4.32 73.26 4.27 3.85 1.02 0.84 2.99 13.77 71.61 3.70 3.78 3.12 2.59 9.01 6.19 73.52 4.75 4.06 1.40 1.68 2.16 12.44 70.78 4.05 3.92 4.22 5.12 6.41 5.50 72.93 5.49 4.22 1.20 1.47 2.46 12.22 70.36 4.69 4.09 3.62 4.51 7.32 5.42 73.01 5.15 4.11 1.46 1.91 2.22 12.13 69.69 4.35 3.94 4.38 5.78 6.54 5.32 72.57 5.71 4.74 1.57 2.87 1.84 10.70 67.82 4.73 4.45 4.61 8.52 5.29 4.59 73.41 4.91 3.61 1.13 1.02 3.24 12.68 70.60 4.18 3.48 3.42 3.10 9.62 5.60 72.65 5.85 3.96 1.18 1.39 3.00 11.97 69.42 4.95 3.80 3.52 4.22 8.84 5.25 72.70 6.73 4.63 1.40 2.51 2.12 9.92 68.11 5.59 4.35 4.10 7.46 6.12 4.27 73.06 5.87 4.48 1.45 2.24 2.30 10.60 68.68 4.88 4.22 4.27 6.68 6.67 4.58 73.39 5.68 4.16 1.38 1.82 2.65 10.91 69.31 4.75 3.95 4.09 5.45 7.72 4.74 72.80 5.92 4.47 1.60 2.91 2.29 10.02 67.15 4.83 4.14 4.63 8.50 6.50 4.25 1 73.55 6.00 4.08 1.43 1.94 2.64 10.36 69.06 4.99 3.85 4.20 5.78 7.65 4.47 72.60 5.68 4.55 1.34 1.69 1.97 12.16 70.19 4.86 4.41 4.07 5.18 5.87 5.40 73.31 4.76 3.92 1.01 0.95 2.62 13.42 71.95 4.13 3.86 3.11 2.97 7.92 6.05 74.19 4.27 3.82 1.21 1.20 2.28 13.02 72.44 3.70 3.75 3.69 3.71 6.87 5.84 72.42 6.20 4.71 1.72 3.11 1.63 10.20 67.28 5.10 4.39 5.01 9.18 4.68 4.36 72.64 5.40 4.62 1.48 2.35 2.05 11.47 68.72 4.52 4.38 4.39 7.04 5.97 4.98 72.46 5.80 4.26 1.51 2.27 2.11 11.58 68.60 4.86 4.05 4.47 6.82 6.16 5.04 73.59 3.19 3.24 0.92 0.24 4.17 14.66 71.53 2.74 3.16 2.79 0.73 12.50 6.55 73.20 5.27 3.71 1.11 1.35 2.89 12.47 70.38 4.49 3.58 3.34 4.13 8.57 5.51 72.15 5.70 4.37 1.73 3.29 2.10 10.66 66.31 4.64 4.03 4.97 9.59 5.96 4.50 73.03 5.21 4.18 1.60 2.58 2.33 11.07 68.07 4.30 3.92 4.66 7.62 6.69 4.74 72.26 7.21 4.89 1.28 2.45 2.14 9.77 67.90 6.00 4.62 3.76 7.30 6.21 4.22 73.41 5.21 4.09 1.37 1.84 2.78 11.30 69.23 4.35 3.87 4.05 5.51 8.09 4.90 72.79 5.62 4.71 1.65 3.51 2.05 9.68 66.45 4.54 4.32 4.70 10.16 5.77 4.06 73.01 6.29 4.41 1.58 3.05 2.23 9.43 67.09 5.12 4.07 4.53 8.89 6.32 3.98 2 72.98 6.35 4.74 1.69 3.82 2.04 8.38 65.80 5.07 4.29 4.77 10.94 5.66 3.47

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210Table F-1 (cont.): EMPA data for LMSX-3 Scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 72.88 4.14 4.14 0.93 0.87 2.73 14.32 71.91 3.60 4.10 2.90 2.71 8.29 6.50 74.41 2.72 4.82 1.74 2.18 1.81 12.31 70.69 2.29 4.60 5.17 6.57 5.31 5.38 72.46 6.26 3.77 1.57 2.08 2.06 11.81 68.98 5.28 3.60 4.67 6.27 6.04 5.17 72.68 5.32 4.83 1.64 2.57 1.76 11.20 68.49 4.44 4.57 4.85 7.69 5.12 4.85 72.46 5.35 5.18 1.79 3.21 1.61 10.41 67.14 4.39 4.81 5.20 9.42 4.59 4.43 73.28 5.12 4.89 1.47 2.45 1.86 10.93 69.23 4.29 4.63 4.36 7.33 5.41 4.74 72.60 5.80 4.61 1.31 2.27 2.09 11.31 68.93 4.88 4.40 3.90 6.84 6.13 4.94 75.18 3.37 3.36 1.37 1.48 2.60 12.63 72.05 2.86 3.2 4.12 4.49 7.68 5.56 72.30 5.96 3.82 1.46 2.19 2.44 11.83 68.27 4.99 3.62 4.32 6.56 7.11 5.13 73.85 4.85 4.17 1.11 1.50 2.80 11.71 70.60 4.11 4.00 3.33 4.54 8.26 5.15 73.17 4.69 3.97 1.43 1.50 3.05 12.20 69.33 3.94 3.77 4.24 4.52 8.89 5.31 72.53 5.74 4.54 1.79 3.44 2.09 9.87 66.13 4.63 4.15 5.12 9.94 5.88 4.13 71.08 7.38 5.11 1.38 2.16 2.30 10.58 67.12 6.17 4.84 4.08 6.48 6.71 4.59 72.66 6.49 4.37 1.51 3.24 2.08 9.63 66.88 5.29 4.05 4.34 9.45 5.91 4.08 3 74.08 4.58 4.37 1.64 3.48 2.32 9.54 67.22 3.68 3.98 4.65 10.01 6.48 3.98 78.86 4.29 4.41 0.91 0.70 1.78 9.05 77.47 3.74 4.35 2.79 2.19 5.38 4.10 73.35 5.17 4.79 1.76 2.67 1.41 10.89 69.16 4.32 4.53 5.20 7.98 4.10 4.70 73.96 5.00 4.45 1.38 1.90 1.70 11.60 71.26 4.27 4.30 4.18 5.82 5.04 5.14 73.27 4.78 4.31 1.16 1.27 2.23 12.97 71.59 4.14 4.23 3.56 3.93 6.73 5.82 72.81 5.24 4.36 1.23 1.23 2.25 12.89 71.09 4.53 4.27 3.76 3.80 6.76 5.78 73.18 4.39 3.99 0.97 0.79 2.64 14.04 72.30 3.84 3.96 3.01 2.47 8.04 6.37 74.15 3.30 3.61 0.91 0.68 2.81 14.54 73.39 2.90 3.59 2.83 2.12 8.57 6.61 73.75 4.57 4.39 1.60 2.49 1.60 11.60 69.99 3.84 4.18 4.76 7.50 4.67 5.06 72.97 4.69 4.84 1.89 2.90 1.50 11.21 68.27 3.89 4.54 5.55 8.60 4.33 4.82 73.19 5.44 4.56 1.51 2.05 1.75 11.51 70.04 4.61 4.38 4.52 6.21 5.17 5.06 73.04 5.26 4.68 1.62 2.43 1.57 11.41 69.40 4.42 4.46 4.81 7.34 4.59 4.98 73.68 4.78 4.28 1.36 1.49 1.92 12.49 71.62 4.11 4.17 4.15 4.60 5.77 5.58 72.93 5.37 4.35 1.20 1.30 2.19 12.66 71.16 4.64 4.26 3.66 4.01 6.58 5.68 73.22 5.40 4.85 1.76 2.88 1.51 10.38 68.47 4.47 4.55 5.15 8.54 4.35 4.46 4 73.64 3.92 4.00 0.93 0.84 2.71 13.96 72.57 3.42 3.96 2.88 2.63 8.22 6.32

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211Table F-1 (cont.): EMPA data for LMSX-3 Scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 79.00 4.21 4.09 0.64 0.42 2.20 9.44 77.99 3.70 4.10 2.00 1.33 6.69 4.30 73.05 5.32 4.32 1.19 1.30 2.29 12.54 71.11 4.54 4.22 3.62 4.00 6.86 5.61 72.92 5.25 4.74 1.29 1.98 1.89 11.94 70.15 4.47 4.57 3.87 6.04 5.61 5.28 73.62 4.81 5.05 1.53 2.26 1.60 11.13 70.14 4.06 4.83 4.57 6.84 4.70 4.87 73.38 4.98 4.66 1.79 2.64 1.45 11.09 69.22 4.16 4.42 5.29 7.90 4.20 4.81 73.83 4.65 3.97 1.08 1.11 2.33 13.03 72.39 4.04 3.90 3.30 3.46 7.03 5.87 72.45 6.02 4.42 1.26 1.42 2.13 12.30 70.43 5.18 4.31 3.84 4.37 6.38 5.49 73.69 5.20 4.70 1.69 2.56 1.45 10.71 69.64 4.36 4.5 5.01 7.67 4.22 4.65 73.13 5.16 4.57 1.52 2.10 1.67 11.83 70.10 4.38 4.41 4.56 6.39 4.95 5.21 75.06 4.72 4.65 1.65 0.00 1.71 12.20 75.09 4.18 4.67 5.17 0.00 5.27 5.61 73.22 5.88 4.42 1.07 1.54 2.02 11.86 71.25 5.06 4.32 3.27 4.74 6.06 5.30 73.80 4.88 3.96 1.01 0.92 2.54 12.89 72.40 4.24 3.90 3.11 2.87 7.67 5.81 72.76 7.08 4.60 1.37 1.93 1.70 10.56 69.85 6.02 4.43 4.12 5.89 5.03 4.66 73.56 5.41 4.73 1.33 1.71 1.73 11.52 71.19 4.64 4.59 4.04 5.25 5.17 5.12 5 73.07 5.35 4.93 1.71 2.78 1.45 10.72 68.74 4.46 4.65 5.03 8.29 4.20 4.63 78.48 4.74 4.60 1.15 0.88 1.50 8.66 76.73 4.10 4.51 3.52 2.73 4.51 3.9 72.57 4.75 4.36 1.50 1.86 1.86 13.09 70.11 4.07 4.23 4.55 5.70 5.53 5.81 72.63 6.35 5.22 1.08 1.72 1.82 11.18 70.47 5.46 5.08 3.28 5.28 5.45 4.98 73.98 4.30 3.99 1.21 1.10 2.22 13.21 72.54 3.73 3.93 3.71 3.42 6.71 5.95 72.98 4.82 4.59 1.69 2.29 1.54 12.09 69.69 4.07 4.40 5.06 6.95 4.52 5.30 73.01 4.82 3.95 1.06 0.73 2.60 13.83 72.12 4.22 3.91 3.27 2.28 7.91 6.28 73.11 4.99 4.67 1.46 1.74 1.72 12.30 70.79 4.28 4.54 4.43 5.35 5.13 5.48 73.13 5.02 4.60 1.43 1.69 1.82 12.32 70.82 4.30 4.47 4.32 5.18 5.42 5.48 70.70 7.87 5.10 1.17 1.65 2.06 11.45 68.44 6.75 4.95 3.56 5.06 6.15 5.09 73.56 3.98 3.89 1.27 1.14 2.25 13.91 72.18 3.46 3.83 3.89 3.56 6.81 6.27 73.56 4.69 4.50 1.60 2.13 1.73 11.78 70.22 3.97 4.31 4.78 6.45 5.10 5.17 72.90 4.80 4.57 1.92 2.51 1.52 11.78 68.89 4.01 4.34 5.69 7.53 4.42 5.12 73.04 6.30 5.61 1.80 2.99 1.09 9.17 68.29 5.21 5.26 5.28 8.86 3.15 3.94 72.19 6.19 5.61 1.89 3.50 1.09 9.55 66.81 5.07 5.21 5.46 10.26 3.12 4.06 6 73.29 5.09 4.53 1.67 2.60 1.59 11.23 69.21 4.26 4.29 4.95 7.80 4.62 4.87

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212Table F-1 (cont.): EMPA data for LMSX-3 Scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.21 4.22 4.61 1.21 1.00 1.49 9.25 76.38 3.70 4.50 3.70 3.11 4.48 4.20 73.56 4.80 4.00 1.16 1.37 2.21 12.90 71.73 4.14 3.91 3.55 4.23 6.65 5.78 74.53 3.94 3.83 1.27 1.10 2.24 13.10 72.90 3.41 3.76 3.88 3.40 6.75 5.89 73.66 3.09 3.35 1.04 0.39 2.94 15.53 73.34 2.73 3.35 3.23 1.22 9.02 7.11 73.35 4.29 4.17 1.61 2.17 1.87 12.54 70.00 3.62 3.99 4.81 6.57 5.50 5.50 73.56 4.13 3.97 1.54 1.49 2.06 13.24 71.27 3.55 3.86 4.68 4.59 6.16 5.90 72.61 4.91 4.65 1.86 2.94 1.42 11.63 68.20 4.08 4.38 5.46 8.75 4.11 5.02 72.18 5.94 4.40 1.17 1.41 2.27 12.63 70.20 5.12 4.3 3.56 4.36 6.82 5.65 72.72 5.26 4.03 1.08 0.98 2.50 13.43 71.44 4.58 3.98 3.31 3.05 7.57 6.07 73.52 4.58 3.87 1.23 1.04 2.41 13.35 71.96 3.97 3.81 3.77 3.22 7.28 6.00 74.04 3.79 3.86 1.53 1.53 1.94 13.31 71.87 3.26 3.76 4.66 4.70 5.81 5.94 73.66 2.78 3.27 0.77 0.07 3.58 15.87 73.40 2.45 3.27 2.42 0.21 10.99 7.27 73.37 4.51 4.25 1.66 2.00 1.78 12.44 70.32 3.83 4.08 4.97 6.06 5.26 5.48 72.01 5.85 4.88 1.53 2.45 1.78 11.50 68.29 4.91 4.65 4.55 7.38 5.21 5.01 7 73.87 4.29 4.21 1.44 1.51 1.88 12.80 71.83 3.69 4.11 4.37 4.64 5.63 5.72 78.60 4.47 5.18 1.20 1.38 1.27 7.89 75.98 3.83 5.03 3.65 4.23 3.78 3.50 77.14 4.99 5.01 1.65 2.05 1.09 8.07 73.23 4.20 4.77 4.90 6.18 3.19 3.52 77.55 3.95 4.30 0.86 0.48 2.12 10.73 76.73 3.46 4.27 2.68 1.52 6.47 4.88 76.94 4.54 4.37 1.47 1.13 1.42 10.13 75.02 3.92 4.27 4.49 3.48 4.28 4.54 76.50 4.33 4.71 1.45 1.12 1.38 10.51 74.84 3.75 4.62 4.43 3.47 4.16 4.73 75.04 5.44 4.97 1.87 2.01 1.09 9.59 71.57 4.59 4.75 5.60 6.07 3.21 4.20 74.02 6.25 5.07 1.32 1.18 1.50 10.63 72.56 5.43 4.98 4.05 3.67 4.52 4.79 73.94 5.88 5.46 1.68 1.98 1.22 9.85 70.81 4.99 5.25 5.03 6.00 3.59 4.33 74.32 4.37 4.23 1.41 0.95 1.91 12.81 73.12 3.80 4.18 4.35 2.97 5.79 5.79 73.26 5.55 4.60 1.17 1.11 1.82 12.49 72.30 4.85 4.56 3.61 3.46 5.55 5.66 72.71 6.85 5.73 1.34 2.07 1.26 10.04 70.04 5.84 5.54 4.06 6.33 3.75 4.44 71.79 6.83 6.05 2.09 3.63 0.89 8.72 66.01 5.56 5.58 6.03 10.59 2.53 3.68 73.35 4.99 4.98 1.83 2.75 1.33 10.78 69.02 4.16 4.70 5.40 8.21 3.84 4.66 72.90 4.87 4.87 1.91 2.80 1.41 11.24 68.48 4.05 4.60 5.61 8.34 4.07 4.85 8 72.45 6.11 4.77 1.45 1.89 1.76 11.57 69.71 5.21 4.60 4.36 5.78 5.22 5.12

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213Table F-1 (cont.): EMPA data for LMSX-3 Scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.49 4.40 4.50 1.260.79 1.539.03 76.78 3.80 4.40 3.902.44 4.634.10 73.90 4.06 4.22 1.381.37 1.9913.08 72.07 3.50 4.13 4.224.24 5.975.86 73.96 3.97 4.05 1.301.31 2.0513.35 72.35 3.44 3.98 3.994.05 6.176.00 73.20 5.42 4.55 1.371.93 1.8711.67 70.33 4.61 4.39 4.115.87 5.535.15 73.62 4.10 3.99 1.391.42 2.0913.40 71.69 3.53 3.90 4.234.38 6.276.00 73.65 4.06 4.01 1.641.78 1.8213.04 71.05 3.47 3.88 4.965.43 5.425.78 73.67 4.23 3.79 1.561.75 2.0312.97 70.92 3.61 3.66 4.705.35 6.045.74 73.42 5.22 4.51 1.582.36 1.5811.33 69.86 4.40 4.3 4.727.13 4.644.95 72.07 6.10 4.36 1.351.69 2.0112.41 69.72 5.23 4.24 4.085.20 5.995.52 73.65 4.98 4.21 1.241.48 1.9512.49 71.76 4.29 4.12 3.794.59 5.855.59 73.70 4.05 3.69 1.030.64 2.7114.18 72.90 3.55 3.67 3.192.00 8.256.44 73.20 4.40 4.21 1.251.17 2.1113.66 71.98 3.84 4.16 3.843.64 6.396.17 74.17 2.36 3.09 0.690.08 3.5516.05 74.09 2.09 3.10 2.160.24 10.947.37 73.54 3.93 3.78 1.101.16 2.6013.89 71.85 3.40 3.70 3.373.60 7.836.24 9 72.95 5.86 4.68 1.331.76 1.7711.65 70.56 5.02 4.54 4.035.39 5.285.18 78.99 4.98 5.20 0.981.06 1.337.44 76.98 4.30 5.09 3.003.29 4.003.30 73.03 5.17 4.15 1.592.20 1.8512.03 69.60 4.36 3.97 4.746.64 5.425.27 73.00 4.24 4.11 1.812.24 1.7512.86 69.56 3.58 3.93 5.416.76 5.135.63 72.44 5.69 4.71 1.502.10 1.7111.84 69.46 4.83 4.53 4.506.40 5.065.22 73.27 4.13 3.75 0.870.63 2.7514.61 72.84 3.64 3.74 2.701.98 8.426.67 72.87 4.52 3.89 1.241.14 2.3413.99 71.49 3.93 3.83 3.823.54 7.076.31 73.28 4.68 4.15 1.501.38 1.9713.03 71.32 4.04 4.06 4.564.27 5.925.83 72.74 5.36 4.61 1.732.31 1.5211.72 69.31 4.52 4.41 5.176.99 4.465.13 72.80 4.99 4.48 1.641.96 1.6812.45 70.01 4.25 4.32 4.955.99 4.985.50 71.89 6.16 4.65 1.311.79 1.8312.40 69.71 5.29 4.53 3.975.49 5.485.53 73.33 4.21 4.34 1.531.63 1.8313.12 71.15 3.62 4.23 4.665.03 5.465.85 72.84 5.08 4.66 1.822.95 1.5811.09 68.07 4.20 4.37 5.328.73 4.554.76 72.31 4.72 3.91 1.060.90 2.7714.32 71.08 4.11 3.86 3.272.80 8.406.47 72.81 5.82 4.62 1.492.18 1.5711.51 68.80 4.94 4.45 4.486.64 4.635.07 10 73.64 4.29 3.84 1.050.83 2.5413.76 72.55 3.75 3.80 3.252.60 7.836.23

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214Table F-1 (cont.): EMPA data for LMSX-3 Scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.56 4.15 4.14 0.90 0.46 2.08 9.70 77.37 3.60 4.10 2.80 1.44 6.32 4.40 72.64 6.00 5.40 1.79 3.67 1.17 9.33 66.94 4.90 5.00 5.18 10.72 3.32 3.95 72.67 5.00 4.31 1.30 1.57 2.05 13.10 70.69 4.31 4.21 3.96 4.83 6.14 5.86 72.22 6.02 4.59 1.10 1.38 2.17 12.53 70.52 5.21 4.50 3.36 4.27 6.53 5.62 73.34 5.45 4.83 1.62 2.79 1.34 10.63 69.21 4.55 4.58 4.78 8.36 3.91 4.61 73.94 3.33 3.83 1.13 0.70 2.62 14.46 73.06 2.91 3.80 3.51 2.18 7.98 6.57 72.68 4.83 4.29 1.71 2.25 1.78 12.46 69.25 4.08 4.10 5.10 6.79 5.21 5.46 71.45 6.69 4.80 1.16 1.51 2.12 12.28 69.52 5.76 4.7 3.55 4.65 6.36 5.49 73.34 4.29 3.71 1.17 0.76 2.53 14.20 72.44 3.75 3.68 3.62 2.37 7.69 6.45 73.37 4.62 4.42 1.30 1.56 2.03 12.69 71.23 3.97 4.31 3.95 4.81 6.06 5.66 72.77 5.07 4.21 1.46 1.65 1.95 12.88 70.48 4.35 4.09 4.43 5.08 5.83 5.73 73.05 5.23 4.88 1.67 2.55 1.43 11.18 69.27 4.40 4.65 4.97 7.66 4.18 4.87 70.00 8.60 5.48 1.03 2.11 1.89 10.89 67.39 7.33 5.29 3.10 6.45 5.61 4.82 72.69 4.93 4.76 1.66 2.23 1.63 12.11 69.45 4.17 4.56 4.98 6.74 4.79 5.32 11 74.13 3.62 3.77 1.38 1.15 2.16 13.78 72.60 3.14 3.71 4.25 3.57 6.53 6.20 77.96 4.44 4.97 1.43 1.25 1.36 8.59 75.36 3.80 4.82 4.33 3.82 4.05 3.80 73.23 4.80 4.39 1.49 1.89 1.70 12.49 70.72 4.10 4.26 4.50 5.80 5.07 5.54 73.03 4.75 4.45 1.78 2.62 1.60 11.76 68.93 3.97 4.22 5.26 7.86 4.66 5.10 72.38 6.00 5.26 1.87 3.46 1.25 9.77 66.92 4.91 4.88 5.41 10.14 3.57 4.15 73.48 5.21 4.72 1.55 2.11 1.60 11.33 70.30 4.41 4.53 4.65 6.40 4.72 4.98 73.23 4.95 4.12 0.97 0.80 2.54 13.40 72.29 4.33 4.08 2.99 2.51 7.71 6.08 72.66 5.40 4.89 1.71 2.66 1.59 11.08 68.44 4.51 4.62 5.05 7.95 4.63 4.80 72.36 5.75 4.82 1.58 2.10 1.55 11.84 69.50 4.89 4.64 4.76 6.39 4.59 5.23 72.55 6.54 4.95 1.23 1.93 1.78 11.01 69.86 5.58 4.79 3.71 5.90 5.30 4.87 73.38 5.90 4.98 1.28 2.12 1.53 10.81 70.55 5.02 4.81 3.85 6.47 4.52 4.78 72.96 4.56 4.25 1.24 1.20 2.11 13.68 71.70 3.97 4.19 3.82 3.75 6.39 6.18 73.00 4.63 4.61 1.86 2.77 1.54 11.60 68.61 3.85 4.35 5.46 8.26 4.45 5.01 72.29 6.65 5.04 1.29 2.02 1.83 10.87 69.30 5.65 4.85 3.87 6.14 5.41 4.79 72.31 5.89 4.39 1.26 1.50 2.11 12.54 70.26 5.07 4.28 3.84 4.63 6.32 5.60 12 72.66 5.23 4.86 1.85 2.86 1.43 11.11 68.20 4.35 4.58 5.43 8.52 4.13 4.79

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215Table F-1 (cont.): EMPA data for LMSX-3 Scheil analysis. Atomic Percent Weight Percent Pass Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.72 5.08 4.50 0.95 0.94 1.42 8.38 77.22 4.40 4.40 2.90 2.92 4.30 3.80 73.91 4.65 4.08 1.38 1.68 1.99 12.31 71.36 3.97 3.95 4.18 5.15 5.92 5.46 72.98 5.48 4.81 1.43 2.43 1.74 11.12 69.28 4.61 4.58 4.26 7.32 5.09 4.85 73.08 5.03 4.71 1.67 3.09 1.47 10.95 68.39 4.17 4.42 4.91 9.17 4.24 4.71 73.64 4.26 4.06 1.34 1.45 2.00 13.24 71.82 3.68 3.97 4.10 4.50 6.00 5.93 73.81 4.16 3.75 1.02 0.73 2.70 13.84 72.76 3.63 3.71 3.15 2.28 8.20 6.27 73.70 4.64 3.96 1.23 1.21 2.34 12.91 71.82 4.01 3.88 3.74 3.74 7.04 5.78 73.92 4.15 3.74 1.33 1.14 2.29 13.43 72.22 3.59 3.7 4.06 3.53 6.90 6.03 73.21 4.88 4.10 0.86 0.94 2.69 13.32 71.97 4.25 4.05 2.64 2.93 8.15 6.02 73.71 4.09 3.84 0.88 0.67 2.76 14.05 72.96 3.59 3.81 2.72 2.11 8.42 6.39 73.27 4.88 4.07 1.30 1.32 2.07 13.08 71.59 4.22 3.99 3.97 4.10 6.24 5.87 73.24 5.00 4.49 1.73 2.58 1.56 11.40 69.22 4.19 4.26 5.13 7.72 4.53 4.95 72.38 6.02 4.48 1.23 1.30 2.18 12.42 70.55 5.19 4.39 3.77 4.01 6.54 5.56 73.38 4.94 4.12 1.28 1.30 2.14 12.85 71.59 4.27 4.03 3.90 4.01 6.44 5.76 13 71.58 7.11 5.17 1.19 1.92 1.80 11.24 69.11 6.08 5.01 3.60 5.87 5.35 4.99 78.57 4.64 4.37 0.80 0.53 1.95 9.14 77.44 4.05 4.33 2.47 1.64 5.93 4.10 72.86 5.53 4.42 1.26 1.35 2.10 12.46 70.99 4.78 4.33 3.84 4.17 6.32 5.58 73.30 5.51 4.32 1.27 1.71 1.92 11.97 70.94 4.72 4.20 3.84 5.26 5.72 5.33 73.16 5.43 4.23 1.33 1.66 1.97 12.22 70.80 4.65 4.11 4.03 5.09 5.88 5.44 73.38 4.93 4.77 1.61 2.24 1.57 11.50 70.01 4.17 4.57 4.80 6.79 4.63 5.04 71.77 6.25 4.76 1.27 1.57 2.10 12.28 69.57 5.37 4.63 3.85 4.83 6.28 5.47 74.31 2.89 3.20 0.86 0.29 3.32 15.11 73.65 2.54 3.19 2.68 0.92 10.14 6.88 74.45 3.80 3.43 1.31 1.09 2.15 13.77 73.16 3.30 3.38 4.02 3.40 6.52 6.22 73.32 4.73 3.90 0.96 0.96 2.54 13.58 72.20 4.12 3.86 2.96 3.01 7.70 6.15 73.14 4.55 4.50 1.86 2.68 1.49 11.79 69.00 3.80 4.26 5.49 8.01 4.32 5.11 73.21 4.90 4.31 1.36 1.67 1.88 12.66 71.04 4.21 4.20 4.14 5.14 5.62 5.65 72.59 5.64 5.04 1.72 2.54 1.49 10.97 68.66 4.73 4.79 5.08 7.63 4.35 4.77 73.46 4.71 4.34 1.53 1.90 1.86 12.21 70.54 4.01 4.18 4.59 5.80 5.49 5.39 72.49 5.89 4.02 0.78 0.76 2.69 13.36 71.75 5.16 4.00 2.42 2.40 8.20 6.08 14 70.47 9.66 5.58 0.97 1.87 1.73 9.71 68.15 8.27 5.42 2.95 5.73 5.17 4.31

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216Table F-1 (cont): EMPA data for LMSX-3 Scheil analysis Atomic Percent Weight Percent Ni Cr Co W Re Ta Al Ni Cr Co W Re Ta Al 78.11 4.50 4.28 1.04 0.50 1.80 9.76 77.12 3.93 4.24 3.23 1.57 5.48 4.43 73.26 4.88 4.03 0.91 1.05 2.74 13.13 71.62 4.23 3.95 2.80 3.25 8.25 5.90 71.20 7.88 5.40 1.30 2.37 1.63 10.23 67.88 6.65 5.16 3.87 7.16 4.79 4.48 72.96 5.46 4.50 1.15 1.39 2.13 12.41 71.11 4.71 4.40 3.51 4.30 6.41 5.56 72.49 6.34 5.31 1.81 3.25 1.19 9.60 67.44 5.23 4.96 5.26 9.59 3.42 4.10 72.83 5.37 4.83 1.61 2.41 1.49 11.46 69.37 4.53 4.62 4.80 7.29 4.37 5.02 74.16 3.03 3.29 0.91 0.46 2.98 15.16 73.70 2.67 3.28 2.84 1.44 9.14 6.92 74.03 3.77 3.81 1.27 1.04 2.25 13.84 72.76 3.28 3.76 3.91 3.23 6.81 6.25 73.33 5.21 4.67 1.75 2.70 1.39 10.95 69.19 4.35 4.42 5.18 8.08 4.03 4.75 72.66 4.68 4.52 1.84 2.69 1.57 12.05 68.54 3.91 4.28 5.42 8.05 4.58 5.22 73.81 3.93 3.93 1.50 1.68 1.84 13.30 71.62 3.38 3.83 4.55 5.17 5.51 5.93 72.97 5.01 4.67 1.68 2.21 1.57 11.88 69.70 4.24 4.48 5.04 6.69 4.63 5.22 73.02 5.03 4.27 1.72 2.40 1.70 11.85 69.24 4.23 4.07 5.10 7.22 4.97 5.17 74.06 2.57 3.24 0.73 0.10 3.49 15.81 73.91 2.27 3.25 2.28 0.32 10.72 7.25 15 74.10 2.69 3.26 0.96 0.23 3.36 15.40 73.42 2.36 3.25 2.99 0.72 10.26 7.01

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217 APPENDIX G SCHEIL ANALYSIS DATA AND GRAPHS FOR CMSX-4 This appendix contains the data and graphs that were used to evaluate the accuracy of the analysis used in this study on a co mmon commercial alloy whose properties have been widely examined.

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218 Scheil Analysis for Ni in CMSX-40.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Ni Ni Figure G-1: Scheil curv e for Ni from CMSX-4. Scheil Analysis for Cr in CMSX-40.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Cr Cr Figure G-2: Scheil curv e for Cr from CMSX-4.

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219 Scheil Analysis for Co in CMSX-40.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Co Co Figure G-3: Scheil curv e for Co from CMSX-4. Scheil Analysis for Mo in CMSX-40.00 0.50 1.00 1.50 2.00 2.50 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Mo Mo Figure G-4: Scheil curv e for Mo from CMSX-4.

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220 Scheil Analysis for W in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% W W Figure G-5: Scheil curve for W in CMSX-4. Scheil Analysis for Re in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Re Re Figure G-6: Scheil curve for Re in CMSX-4.

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221 Scheil Analysis for Ta in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Ta Ta Figure G-7: Scheil curv e for Ta from CMSX-4. Scheil Analysis for Al in CMSX-40.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Al Al Figure G-8: Scheil curv e for Al from CMSX-4.

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222 Scheil Analysis for Ti in CMSX-40.00 0.50 1.00 1.50 2.00 2.50 3.00 0.000.100.200.300.400.500.600.700.800.901.00 Vol%wt% Ti Ti Figure G-9: Scheil curv e for Ti from CMSX-4.

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223 Table G-1: Scheil curve data for CMSX-4. Ni Cr Co Mo W Re Ta Al Ti 69.09 15.16 7.57 2.24 1.84 0.00 8.89 7.26 2.42 69.02 13.04 7.68 1.55 2.26 0.17 8.89 7.19 2.27 68.81 12.25 7.70 1.22 2.42 0.19 8.66 7.13 2.17 68.77 11.98 7.74 1.21 2.52 0.31 8.26 7.09 1.94 68.67 11.18 7.75 1.16 2.56 0.36 8.08 7.08 1.90 68.33 10.24 7.88 0.93 2.62 0.46 7.85 7.08 1.88 68.09 9.66 7.91 0.92 2.66 0.64 7.63 6.97 1.85 68.03 9.53 7.95 0.90 2.68 0.72 7.52 6.95 1.83 67.99 9.18 8.02 0.89 2.72 0.75 7.51 6.94 1.80 67.93 9.09 8.05 0.87 3.00 0.76 7.29 6.90 1.77 67.65 8.96 8.08 0.86 3.03 0.78 7.01 6.88 1.72 67.61 8.93 8.16 0.85 3.04 0.80 6.96 6.87 1.72 67.59 8.83 8.20 0.84 3.06 0.92 6.94 6.86 1.69 67.53 8.67 8.21 0.84 3.07 0.92 6.91 6.86 1.63 67.41 8.00 8.23 0.83 3.14 0.95 6.88 6.82 1.61 67.39 7.90 8.27 0.81 3.16 0.95 6.77 6.81 1.61 67.37 7.78 8.27 0.81 3.17 0.96 6.76 6.79 1.60 67.35 7.72 8.32 0.80 3.18 1.02 6.70 6.77 1.60 67.26 7.66 8.42 0.79 3.22 1.05 6.60 6.73 1.59 67.22 7.59 8.42 0.77 3.23 1.13 6.42 6.63 1.55 66.84 7.56 8.50 0.77 3.31 1.30 6.37 6.61 1.53 66.56 7.53 8.54 0.77 3.37 1.46 6.32 6.55 1.53 66.48 7.46 8.87 0.75 3.37 1.49 6.28 6.54 1.50 66.45 7.35 8.88 0.75 3.38 1.52 6.12 6.54 1.49 66.38 7.31 8.90 0.75 3.42 1.55 6.03 6.52 1.48 66.11 7.28 8.92 0.74 3.51 1.56 6.03 6.47 1.47 65.90 7.26 8.93 0.73 3.59 1.66 6.00 6.46 1.42 65.87 7.16 8.98 0.72 3.69 1.70 5.86 6.46 1.41 65.72 7.16 9.00 0.72 3.72 1.74 5.85 6.42 1.40 65.70 6.98 9.00 0.69 3.73 1.75 5.80 6.42 1.36 65.61 6.97 9.04 0.69 3.76 1.77 5.70 6.39 1.35 65.53 6.88 9.05 0.68 3.76 1.77 5.62 6.39 1.32 65.47 6.81 9.13 0.67 3.77 1.81 5.57 6.38 1.31 65.47 6.60 9.14 0.67 3.78 1.86 5.57 6.37 1.30 65.41 6.54 9.14 0.66 3.79 1.92 5.53 6.37 1.30 65.40 6.50 9.15 0.64 3.82 1.93 5.41 6.36 1.28 65.32 6.45 9.25 0.63 3.83 1.94 5.37 6.36 1.27 65.30 6.41 9.26 0.62 3.86 1.97 5.34 6.32 1.25 65.28 6.29 9.32 0.62 3.87 1.97 5.29 6.24 1.25 65.25 6.26 9.32 0.61 3.91 2.02 5.29 6.21 1.24 65.10 6.23 9.34 0.61 3.93 2.05 5.26 6.15 1.24 65.09 6.20 9.35 0.61 3.94 2.10 5.20 6.15 1.22 65.07 6.19 9.39 0.60 3.95 2.13 5.19 6.12 1.22

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224 Table G-1 (cont.): Scheil curve data for CMSX-4. Ni Cr Co Mo W Re Ta Al Ti 65.06 6.18 9.40 0.60 4.04 2.13 5.09 6.10 1.20 64.84 6.16 9.41 0.59 4.04 2.19 5.03 6.04 1.20 64.82 6.08 9.43 0.59 4.06 2.20 4.92 6.02 1.20 64.75 6.05 9.49 0.59 4.07 2.36 4.90 6.02 1.19 64.75 6.03 9.62 0.58 4.14 2.39 4.87 6.01 1.19 64.56 6.03 9.67 0.58 4.14 2.41 4.87 6.01 1.19 64.47 5.90 9.79 0.58 4.17 2.48 4.86 5.99 1.18 64.22 5.89 9.82 0.58 4.18 2.50 4.84 5.95 1.17 64.08 5.87 9.85 0.57 4.19 2.55 4.83 5.90 1.14 64.04 5.79 9.90 0.57 4.21 2.57 4.81 5.85 1.13 63.66 5.71 9.91 0.56 4.21 2.63 4.79 5.81 1.13 63.61 5.70 9.96 0.55 4.22 2.64 4.69 5.78 1.12 63.55 5.66 10.03 0.55 4.23 2.72 4.59 5.76 1.11 63.55 5.64 10.08 0.54 4.24 2.73 4.57 5.74 1.09 63.54 5.53 10.08 0.54 4.26 2.74 4.56 5.73 1.09 63.39 5.44 10.09 0.54 4.27 2.83 4.51 5.72 1.08 63.35 5.42 10.13 0.54 4.32 2.83 4.49 5.72 1.08 63.33 5.41 10.13 0.54 4.33 2.93 4.48 5.72 1.06 63.26 5.41 10.15 0.54 4.36 2.94 4.36 5.70 1.06 63.04 5.38 10.18 0.54 4.39 2.98 4.24 5.63 1.02 62.84 5.30 10.19 0.53 4.48 3.05 4.20 5.59 1.00 62.63 5.29 10.20 0.53 4.49 3.16 4.19 5.46 0.96 62.58 5.27 10.31 0.52 4.57 3.32 4.05 5.45 0.96 62.50 5.22 10.56 0.51 4.57 3.33 3.87 5.43 0.95 62.18 5.15 10.59 0.50 4.64 3.44 3.85 5.40 0.95 62.06 5.11 10.59 0.50 4.70 3.54 3.85 5.37 0.94 61.83 5.08 10.62 0.48 4.75 3.60 3.77 5.30 0.93 61.77 4.62 10.73 0.48 4.83 3.71 3.73 5.09 0.88 61.69 4.60 10.76 0.48 4.89 3.71 3.66 5.06 0.87 61.68 4.58 10.90 0.48 4.90 3.72 3.65 5.01 0.86 61.64 4.44 10.95 0.47 4.90 3.80 3.52 4.98 0.85 61.62 4.40 11.10 0.46 5.20 3.95 3.51 4.96 0.82 61.62 4.38 11.10 0.46 5.21 4.00 3.45 4.96 0.80 61.45 4.30 11.19 0.45 5.32 4.02 3.43 4.92 0.79 61.42 4.26 11.22 0.44 5.69 4.20 3.38 4.90 0.71 61.20 4.17 11.27 0.44 5.89 4.41 3.17 4.87 0.70 61.07 4.04 11.31 0.43 5.96 4.43 3.01 4.87 0.69 60.48 4.01 11.54 0.41 6.19 4.69 2.98 4.83 0.66 60.43 3.86 11.56 0.41 6.19 4.89 2.93 4.83 0.64 60.40 3.80 11.56 0.39 6.26 4.91 2.93 4.82 0.63 59.89 3.49 11.64 0.37 6.35 5.05 2.89 4.81 0.62 58.91 3.39 11.67 0.30 6.48 5.10 2.88 4.73 0.62

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225 Table G-1 (cont.): Scheil curve data for CMSX-4. Ni Cr Co Mo W Re Ta Al Ti 58.18 3.16 11.78 0.30 6.50 5.15 2.84 4.63 0.61 57.94 3.11 12.32 0.27 6.53 5.22 2.80 4.60 0.61 56.63 3.09 12.36 0.25 6.55 5.36 2.66 4.04 0.58 56.42 3.03 12.47 0.25 6.56 5.41 2.34 3.97 0.54 54.26 2.88 13.19 0.21 6.57 5.77 1.97 3.91 0.51

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230 BIOGRAPHICAL SKETCH Eric C. Caldwell was born in June 1969 in suburbs of Los Angeles, California. He graduated from Glendora High School in June 1 987. After graduation he then enlisted in the United States Navy where he attended the Naval Nuclear Power School and earned his qualification to operate a naval nuclea r reactor engine room. He was honorably discharged in 1995 after eight years of service with the fi nal rank of MM1/SS and serving on two fast attack submarines and one submar ine tender. Upon receiving his discharge, he immediately enrolled at th e University of Florida, and joined the Department of Materials Science and Engineering in 1998, and readily began an internship with Pratt & Whitney GESP in West Palm Beach, FL. He gr aduated with a bachelors degree in this field in May 2000, and began a co-operati ve employment program with Siemens Westinghouse in Orlando, FL. In January 2001 he returned to the University of Florida to pursue a graduate degree in materials science and engineering. He is the recipient of the 2001 International Symposium on Superall oys Scholarship. He is currently scheduled to graduate with a Master of Science degree in August 2004 and will begin working for ExxonMobil Development in Houston, TX, shortly thereafter.