Modelling & Simulation
Insight in Ti-Ta high-temperature shape memory alloys from first principles
Tanmoy Chakraborty, ICAMS, Ruhr-Universität Bochum, Bochum, GermanyJutta Rogal, ICAMS, Ruhr-Universität Bochum, Bochum, GermanyRalf Drautz, ICAMS, Ruhr-Universität Bochum, Bochum, Germany
Ti-Ta alloys show high martensitic transformation temperatures and good workability, which makes them suitable candidates for high-temperature shape memory alloys (HTSMAs). Insight into the composition dependence of the martensitic start temperature (Ms) and other properties is, however, still missing.
Using density functional theory (DFT) calculations we predict the free energies of the martensite and austenite phase as a function of composition and obtain an estimate for the composition dependence of Ms. Our predicted change in Ms with composition is in good agreement with available experimental results. We also calculate the composition dependence of the elastic properties of martensite and austenite, which not only are important for the Ms but also indicate phase stability and anisotropic properties of the martensite phase.
From our calculations we identify a one dimensional descriptor for the estimation of the transformation temperature that may be used in high-throughput screening of ternary or multicomponent alloys for a computationally guided development of novel HTSMAs.