An atomistic view on Oxygen, antisites and vacancies in the γ-TiAl phase

V.I. Razumovskiy, Werner Ecker, David Wimler, Franz-Dieter Fischer, Fritz Appel, Svea Mayer, Helmut Clemens

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

1 Zitat (Scopus)

Abstract

The ordered intermetallic γ-TiAl phase plays an important role in determining mechanical properties of engineering γ-TiAl based alloys. During alloy production, interstitial O is introduced in these alloys and in the γ-phase in particular. It is anticipated that it can have a significant impact on mechanical properties of the alloys due to localized dislocation pinning at O atoms and other point defects. In this paper, we apply a standard thermodynamic approach concerning point-defects in ordered compounds together with density functional theory and finite element method calculations to investigate the impact of O on thermal point defect formation and the associated defect formation eigenstrains in the practically relevant Ti-rich off-stoichiometric γ-TiAl phase. The results show that O is strongly bound to vacancies and Ti antisite defects and may substantially increase their equilibrium concentration. Calculated concentrations and eigenstrain values of antisites and vacancies in the presence of O offer a possibility of their interaction with dislocations, promoting dislocations pinning within the strain aging temperature regime of TiAl alloys.

OriginalspracheEnglisch
Aufsatznummer110655
Seitenumfang8
FachzeitschriftComputational materials science
Jahrgang197.2021
AusgabenummerSeptember
DOIs
PublikationsstatusVeröffentlicht - Sept. 2021

Bibliographische Notiz

Funding Information:
The authors gratefully acknowledge the financial support under the scope of the COMET program within the K2 Center ?Integrated Computational Material, Process and Product Engineering (IC-MPPE)? (Project No. 859480). This program is supported by the Austrian Federal Ministries for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK) and for Digital and Economic Affairs (BMDW), represented by the Austrian Research Funding Association (FFG), and the federal states of Styria, Upper Austria, and Tyrol. The computational results presented have been obtained using the Vienna Scientific Cluster (VSC). Data availability The raw/processed data required to reproduce these findings cannot be contributed at this time since the data also form a part of an ongoing study.

Funding Information:
The authors gratefully acknowledge the financial support under the scope of the COMET program within the K2 Center “Integrated Computational Material, Process and Product Engineering (IC-MPPE)” (Project No. 859480). This program is supported by the Austrian Federal Ministries for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK) and for Digital and Economic Affairs (BMDW), represented by the Austrian Research Funding Association (FFG), and the federal states of Styria, Upper Austria, and Tyrol. The computational results presented have been obtained using the Vienna Scientific Cluster (VSC). Data availability The raw/processed data required to reproduce these findings cannot be contributed at this time since the data also form a part of an ongoing study.

Publisher Copyright:
© 2021 Elsevier B.V.

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