Alloy design by tailoring phase stability in commercial Ti alloys

G. H. Zhao, X. Z. Liang, X. Xu, M. B. Gamża, H. Mao, D. V. Louzguine-Luzgin, P. E.J. Rivera-Díaz-del-Castillo

Research output: Contribution to journalArticlepeer-review

Abstract

The mechanical characteristics and the operative deformation mechanisms of a metallic alloy can be optimised by explicitly controlling phase stability. Here an integrated thermoelastic and pseudoelastic model is presented to evaluate the β stability in Ti alloys. The energy landscape of β→α martensitic transformation was expressed in terms of the dilatational and transformational strain energy, the Gibbs free energy change, the external mechanical work as well as the internal frictional resistance. To test the model, new alloys were developed by tailoring two base alloys, Ti–6Al–4V and Ti–6Al–7Nb, with the addition of β-stabilising element Mo. The alloys exhibited versatile mechanical behaviours with enhanced plasticity. Martensitic nucleation and growth was fundamentally dominated by the competition between elastic strain energy and chemical driving force, where the latter term tends to lower the transformational energy barrier. The model incorporates thermodynamics and micromechanics to quantitatively investigate the threshold energy for operating transformation-induced plasticity and further guides alloy design.

Original languageEnglish
Article number141229
JournalMaterials Science and Engineering A
Volume815
DOIs
Publication statusPublished - 2021 May 20

Keywords

  • Alloy design
  • Phase transformation
  • Physical modelling
  • Plasticity
  • Ti alloys

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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