Unusual precipitation induced by solute segregation in coherent twin boundary in titanium alloys

Chaoqiang Liu, Xin Hu, Lin Qi, Houwen Chen, Zhiqiao Li, Xiaoyong Zhang, Hongge Yan, Kechao Zhou, Min Song, Yunzhi Wang, Jian Feng Nie

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)


Heterogeneous precipitation and hence the distribution of α and β phase in α+β titanium alloys can impact strongly on alloy mechanical properties. The β phase is commonly observed to precipitate heterogeneously at boundaries between α′ martensite plates and dislocations inside the martensite, especially in the additively manufactured α+β titanium alloys, with a Burgers orientation relationship with the surrounding matrix phase. Here, we report an interesting phenomenon in a Ti-4wt%Mo alloy where the β phase precipitates heterogeneously on Mo-segregated {101¯1} fully coherent twin boundaries (CTBs) within α′ martensite, with an unusual Potter orientation relationship with α′. We find that the CTB has a structure resembling that of the β phase and that Mo segregation in the CTB leads to an unusual out-of-plane shift of the segregated atomic columns that makes the local structure almost identical to the β structure, hence serving as a template for β precipitation with the unique orientation relationship. Our findings reveal a novel mechanism via which the distribution of β precipitates can be manipulated effectively for better mechanical properties and could be extended to a group of Ti alloys including the current workhorse alloy Ti-6Al-4V and more broadly to other engineering alloys.

Original languageEnglish
Article number118466
Number of pages13
JournalActa Materialia
Publication statusPublished - 1 Jan 2023


  • Precipitation
  • Solute segregation
  • Titanium alloys
  • Twin boundary

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