On the energetics of the cubic-to-hexagonal transformations in TiAl+Mo alloys

Research output: Contribution to journalArticleResearchpeer-review

Authors

  • Mohammed Dehghani
  • Andrei V. Ruban
  • Martin Friák
  • Mojmír Šob
  • J. Spitaler

External Organisational units

  • Materials Center Leoben Forschungs GmbH
  • Masaryk University
  • KTH-Royal Institute of Technology
  • Brno University of Technology
  • Institute of Physics of Materials of the Academy of Sciences of the Czech Republic

Abstract

Diffusionless transformations allow access to metastable phases and enrich the materials design portfolio. They are well suited for atomistic modeling; nonetheless, they are challenging when involving disordered systems or alloys with complex compositions. This work presents a comprehensive study of transformation energetics between bcc and hcp ordered and disordered phases in the TiAl+Mo model alloy system. By employing two complementary techniques I. VASP-SQS, and II. EMTO-CPA, we can show that chemical disorder flattens the energy landscape but may introduce a small barrier. Unlike that, the energetics of ordered phases are barrier-less and hence would suggest a spontaneous transformation. Finally, we show that Mo stabilizes the bcc phases, leading to a barrier-less transformation hcpbcc for both ordered and disordered states when Mo content exceeds at.%.

Details

Original languageEnglish
Pages (from-to)118268
Number of pages9
JournalActa materialia
Volume240.2022
Issue numberNovember
DOIs
Publication statusE-pub ahead of print - 24 Aug 2022