Citation
Assessment Of Diffusion Mobilities In Hcp Mg-Li-Al Alloys

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Title:
Assessment Of Diffusion Mobilities In Hcp Mg-Li-Al Alloys
Series Title:
19th Annual Undergraduate Research Symposium
Creator:
Cleri, Angela
Language:
English
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Undetermined

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Center for Undergraduate Research
Center for Undergraduate Research
Genre:
Conference papers and proceedings
Poster

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Abstract:
Software such as ThermoCalc is commonly used in alloy design as a database of information for different alloy systems. This study focuses on generating data about the kinetics of Mg-Li-Al systems to be made more accessible using such software for future alloy design using this system. Samples of Mg, Mg-Li, Mg-Al, and Mg-Li-Al were first analyzed using inductively-coupled plasma (ICP) optical emission spectra (OES) to determine the absolute composition of the alloys. Diffusion couples were formed between samples of Mg//Mg-Li, Mg-Li//Mg-Li-Al, and Mg-Al//Mg-Li-Al. Then, electron probe microanalysis (EPMA) and auger electron spectroscopy (AES) were used to analyze line scans across the diffusion profiles in each diffusion couple. ( en )
General Note:
Research authors: Philipp Alieninov, David Christianson, Josh Wagner, Angela Cleri, Michele Manuel - University of Florida
General Note:
University Scholars Program
General Note:
Faculty Mentor: Software such as ThermoCalc is commonly used in alloy design as a database of information for different alloy systems. This study focuses on generating data about the kinetics of Mg-Li-Al systems to be made more accessible using such software for future alloy design using this system. Samples of Mg, Mg-Li, Mg-Al, and Mg-Li-Al were first analyzed using inductively-coupled plasma (ICP) optical emission spectra (OES) to determine the absolute composition of the alloys. Diffusion couples were formed between samples of Mg//Mg-Li, Mg-Li//Mg-Li-Al, and Mg-Al//Mg-Li-Al. Then, electron probe microanalysis (EPMA) and auger electron spectroscopy (AES) were used to analyze line scans across the diffusion profiles in each diffusion couple. - Center for Undergraduate Research, University Scholars Program

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University of Florida
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Copyright Angela Cleri. 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.

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ABSTRACT Software such as ThermoCalc is commonly used in alloy design as a database of information for different alloy systems This study focuses on generating data about the kinetics of Mg Li Al systems to be made more accessible using such software for future alloy design using this system Samples of Mg, Mg 5 Li, Mg 5 Al, and Mg 5 Li 5 Al were first casted and analyzed using inductively coupled plasma (ICP) optical emission spectra (OES) to determine the absolute composition of the alloys Diffusion couples were formed between samples of Mg//Mg Li, Mg Li//Mg Li Al, and Mg Al//Mg Li Al Then, auger electron spectroscopy (AES) and electron probe microanalysis (EPMA) for wavelength dispersive X Ray spectroscopy (WDS) were used to analyze line scans across the diffusion profiles in each diffusion couple Assessment of Diffusion Mobilities in HCP Mg Li Al Alloys Angela Cleri, David Christianson, Josh Wagner, Philipp Alieninov Michele Manuel Department of Materials Science and Engineering, University of Florida, Gainesville, FL INTRODUCTION Automotive and aerospace industries require lightweight alloy design Mg Li Al has potential for such applications Little documentation on fundamental kinetic properties of system Require information on diffusion driven processes (homogenization, precipitation strengthening, etc ) Study aims to obtain data on kinetics of Mg Li Al alloys Make data accessible via ThermoCalc to allow for computational approaches for future alloy design METHOD Cast samples in inert argon atmosphere Analyze samples using ICP OES Determine bulk composition of the alloys Diffusion couples assembled and encapsulated in vacuum sealed Pyrex tubes Diffusion couples heated at various temperatures Analyze line scans across diffusion profiles using EPMA and AES INDUSTRY RELEVANCE Need for development of lightweight alloys in automotive and aerospace industries improved fuel efficiency Automotive industry historically dominated by steel high strength Aerospace industry dominated by aluminum light weight Mg for structural applications currently a popular area of study Mg Li Al has potential to replace traditionally used materials because of low mass and high strength CONCLUSION This study will provide accessible data about the kinetic properties of Mg Li Al systems for future alloy design in the automotive and aerospace industries With such data more available through mediums such as ThermoCalc future alloy design can incorporate computational approaches to predict diffusion driven processes rather than depending entirely on experiments FUTURE WORK To complete this study, EPMA and AES will be used to analyze line scans across the diffusion profiles for each sample combination Final results will be submitted to the CALPHAD journal and the data will be added to the ThermoCalc database REFERENCES [ 1 ] Busk, R S Transactions AIME, 188 1460 ( 1950 ) [ 2 ] Hauser, F E et al Transaction ASM, 50 856 ( 1958 ) [ 3 ] Zheng, Z et al ( 2016 ) Rate sensitivity in discrete dislocation plasticity in hexagonal close packed crystals Acta Materialia 17 26 [ 4 ] Callister, W D et al ( 2012 ) Fundamentals of Materials Science and Engineering John Wiley & Sons, Inc 266 [ 5 ] NASA ( 2017 November 1 ) Briefings, NASA Television Coverage Set for Launch of NOAA Weather Satellite Retrieved from Science Beta [ 6 ] University of Waterloo ( 2017 May 8 ) Fundamentals of Materials Science and Engineering John Wiley & Sons, Inc BACKGROUND Magnesium Lightest structural metal HCP crystal structure has few slip planes low ductility Lithium Improve room temperature ductility o Decrease c/a ratio of Mg lattice [ 1 ] o May allow lattice to slip in prismatic and basal planes [ 2 ] Lightest metal further reduces alloy density Binary Mg Li system is soft low mechanical strength Aluminum Alloying can allow formation of strengthening precipitates RESULTS Mg Mg 5Li Mg 5Li Mg 5Li 5Al Mg 5Al Mg 5Li 5Al Temperature 400 C 450 C 500 C Time 48 hr 24 hr 24 hr Mg Li Al Steel Density (g/cm 3 ) 1.74 0.53 2.70 7.75 Alloy Mg wt % Li wt % Al wt % Mg 5Li 93.5 6.5 -Mg 5Al 95.1 -4.9 Mg 5Li 5Al 90.2 4.9 4.9 Samples: Mg Mg 5Li Mg 5Al Mg 5Li 5Al Table 1: Comparison of relative densities of materials [4] Figure 1: HCP Slip Planes [3] Figure 2: Assembled diffusion couple Figure 3: Diffusion couple encapsulated in vacuum sealed Pyrex tube prior to furnace heat treatment Table 2: Bulk composition of casted samples determined through ICP OES Figure 7: Theoretical diffusion profile of Mg//Mg 5Li Figure 4 6: Optical images of Mg//Mg 5Li diffusion couple interface Figure 8 9: Potential applications for Mg Li Al alloys in the aerospace and automotive industries [5] [6]