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MM: Fachverband Metall- und Materialphysik

MM 60: Microstructure and Phase Transformations III

MM 60.4: Vortrag

Donnerstag, 10. März 2016, 16:30–16:45, H39

Density functional theory investigation of elastic properties and martensitic transformation of Ti-Ta alloys — •Tanmoy Chakraborty, Jutta Rogal, and Ralf Drautz — Interdisciplinary Centre for Advanced Materials Simulation, Ruhr- Universität Bochum, 44780 Bochum, Germany

Ti-Ta alloys are considered as promising materials for high temperature shape memory alloys as well as biomedical applications. The properties of these alloys have been shown to be strongly composition dependent. The temperature for the martensitic transformation between the high temperautre cubic austenite and the low temperature orthorhombic martensite decreases linearly with increasing Ta content. Likewise, the elastic properties show clear trends with changing composition. We use density functional theory to investigate the involved phases in Ti-Ta where the disordered phases are treated by special quasi-random structures. To compare the stability of the involved phases as a function of temperature we calculate free energies using the quasi-harmonic Debye model. The obtained trends in the stability are consistent with experimentally measured transformation temperatures. Furthermore, we determine elastic properties which are in good agreement with experimentally observed trends.