Structural stability and mechanical properties of TiAl+Mo alloys: A comprehensive ab initio study

Neda Abdoshahi, Mohammad Dehghani, Lukas Hatzenbichler, Petra Spörk-Erdely, Andrei V. Ruban, Michael Musi, Svea Mayer, J. Spitaler, David Holec

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung


Titanium aluminides are technologically important intermetallic alloys with also many curious properties interesting from a basic research point of view. When alloyed with Mo, several (meta)stable phases have been reported; their properties are, however, largely unknown due to the alloy processing (e.g. fast cooling) and/or non-existence as a single-phase material. Here we employ first principles calculations to study compositional trends in structural and mechanical properties. We could show that Mo increases the density of all studied phases, leads to their chemical destabilization with the exception of the ordered bcc β o phase, increases their ductility, and enhances the elastic anisotropy. Discrepancies between two employed ab initio methods (special quasi-random structures vs. coherent potential approximation) in the case of the β o and B19 phases are rationalized with significant local distortions which may eventually facilitate a spontaneous phase transformation. Predictions of ordering temperatures solely based on the configurational entropy do not yield values in the experimentally expected ranges.

FachzeitschriftActa materialia
Frühes Online-Datum30 Okt. 2021
PublikationsstatusVeröffentlicht - Dez. 2021

Bibliographische Notiz

Funding Information:
This research was funded by the Austrian Science Fund (FWF) Project Number P29731-N36. The computational results presented have been achieved in part using the Vienna Scientific Cluster (VSC). Parts of Figs. 1 and 10 were visualized using the VESTA package [57] .

Publisher Copyright:
© 2021 The Author(s)

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