Introducing transformation twins in titanium alloys: an evolution of α-variants during additive manufacturing

H. Wang, Qi Chao, L. Yang, M. Cabral, Z. Z. Song, B. Y. Wang, S. Primig, Wei Xu, Z. B. Chen, S. P. Ringer, X. Z. Liao

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34 Citations (Scopus)

Abstract

Titanium alloys can experience a cooling-induced phase transformation from a body-centred cubic phase into a hexagonal close-packed phase which occurs in 12 crystallographically equivalent variants. Among them, variant selection II, 60°/ (Formula presented.), is very close to the orientation of (Formula presented.) twins (57.42°/ (Formula presented.)). We propose that the cyclic thermal loading during additive manufacturing introduces large thermal stresses at high temperature, enabling grain reorientation that transforms the 60°/ (Formula presented.) variant boundaries into the more energetically stable 57.42°/ (Formula presented.) twin boundaries. This transformation twinning phenomenon follows a strain accommodation mechanism and the resulting boundary structure benefits the mechanical properties and thermal stability of titanium alloys.

Original languageEnglish
Pages (from-to)119-126
Number of pages8
JournalMaterials Research Letters
Volume9
Issue number3
DOIs
Publication statusPublished - 2021

Keywords

  • additive manufacturing
  • Titanium alloy
  • twinning mechanism
  • variant selections

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