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MM: Fachverband Metall- und Materialphysik

MM 30: Methods in Computational Materials Modelling III: Thermodynamics

MM 30.5: Talk

Wednesday, March 18, 2015, 11:15–11:30, H 0106

First principles study of competing phases in binary Ti-Ta alloys — •tanmoy chakraborty, jutta rogal, and ralf drautz — ICAMS, Ruhr-Universität Bochum, 44780 Bochum, Germany

Ti-Ta shows a stable reversible martensitic phase transformation with a transformation temperature well above 350 K. This makes the material relevant for high temperature shape memory alloy (HTSMA) applications. In our study we use density-functional theory (DFT) in combination with the solid-state nudged elastic band (SSNEB) method to analyse the minimum energy paths along the transformation between different phases. From the relative stability of the phases as a function of Ta concentration we estimate trends in transformation temperature. The calculated phonon spectra provide insight into the dynamical stability of the phases and are used to assess thermal properties. Our results predict a range of 20-35 at.% Ta to be most suitable for a stable Ti-Ta based HTSMA.