Regensburg 2010 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 12: Topical Session Designing Innovative Structural Materials and Steels III
MM 12.3: Vortrag
Montag, 22. März 2010, 15:15–15:30, H4
The influence of interstitial carbon and substitutional Nb-Mo on the mechanical properties of Ti-Al - an ab initio study — •Dominik Legut1,2, Juergen Spitaler1,2, and Claudia Ambrosch-Draxl1 — 1Chair of Atomistic Modelling and Design of Materials, University of Leoben, Leoben, Austria — 2Materials Center Leoben, Leoben, Austria
Ti-Al based alloys exhibit very attractive properties such as low density, high strength at high temperatures, and very good oxidation resistance, but they are brittle at room temperature. Addition of transition elements or elements like carbon, nitrogen and oxygen can significantly improve their behavior regarding strength and ductility. We perform first-principles calculations based on density functional theory to investigate the influence of interstitial carbon on the energetics of both, the α2 (L10) and γ (DO19) structure of this alloy. The elastic constants of Ti-Al alloys with interstitial carbon are calculated and compared to the results for the pure α2 and γ Ti-Al phases. Moreover, we study the quaternary system Ti-Al-Nb-Mo, where we determine the positions of Nb and Mo with respect to each other. Also the heat of formation is predicted for Nb-Mo concentrations which resemble the real alloy compositions.