Tuning deformation behavior via controlled α precipitation in ω-enriched metastable β titanium alloys

作者：Jianfa Jing, C.Y. Chen, Rong Chen, Xu Huang, Minjie Lai · 发表于：Materials & Design · 年份：2025 · DOI：10.1016/j.matdes.2025.115120 · 被引用次数：2 · 研究领域：Titanium Alloys Microstructure and Properties、Magnesium Alloys: Properties and Applications、Fatigue and fracture mechanics

• Minor α precipitation mitigates ω-induced embrittlement while preserving strength. • ω phase does not effectively assist in α nucleation during aging. • Controlled α precipitation effectively tunes deformation mechanisms. The deformation behavior of a metastable β-type Ti-12Mo-1Al (wt.%) model alloy was investigated in three aged states with varying α precipitation: (i) α-free, (ii) α-lean, and (iii) α-dominated. The first two are ω-enriched, whereas the third is ω-lean. In the ω-enriched states, plastic deformation is governed by dislocation channeling, with dislocation motion localized in ω-devoid channels. In the α-free state, the substantial volume fraction of ω precipitates ( f > 65 %) resists dislocation motion, leading to severe plastic deformation localization and limited elongation to fracture (ETF < 2.5 %) despite high yield strength (YS > 1250 MPa). In the α-lean state, minor α precipitates ( f < 15 %) reduce the ω content by >35 %, facilitating dislocation channeling and activating deformation twinning and stress-induced α'' martensitic transformation. By delocalizing plastic deformation and suppressing intergranular cracking, these mechanisms collectively mitigate ω-induced embrittlement, achieving enhanced ETF (∼11.19 %) without compromising YS (>1000 MPa). The α-dominated state ( f ∼ 48 % α), in contrast to the α-lean state, exhibits grain-confined dislocation activity and widespread intergranular cracking, leading to a reduced ETF (∼4.79 %). These findings u...