About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
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Computational Discovery and Design of Emerging Materials
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Presentation Title |
Tunability of Martensitic Transformation in Mg-Sc Shape Memory Alloys: a DFT Study |
Author(s) |
Shivam Tripathi, Karthik Guda Vishnu, Michael Titus, Alejandro Strachan |
On-Site Speaker (Planned) |
Shivam Tripathi |
Abstract Scope |
Low density makes Mg-Sc shape memory alloys attractive for a wide range of applications, unfortunately use of these alloys is hindered by low martensitic transformation temperature(173K). We use DFT to characterize the energetics associated with the martensitic transformation in a Mg-Sc(19.44at.% Sc) alloy from a disordered BCC austenite to a disordered orthorhombic martensite. The simulations predict lattice parameters and XRD in good agreement with experiments and the martensite to be 10.5 meV/atom lower in energy than austenite at zero temperature. We also explore the effect of epitaxial strain with the objective of increasing the transformation temperature. Bi-axial strain between 5 and 7% increases the zero-temperature energy difference between the phases by over 60%. Similar stabilization of the martensite can be achieved by the addition of pure Mg as a coherent second phase. These results indicate that coherency strains can be used to increase the martensitic transformation temperature to room temperature. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |