Dependence of stress-induced omega transition and mechanical twinning on phase stability in metastable β Ti-V alloys

Tensile properties and deformation microstructures of a series of binary β Ti-16-22V alloys have been investigated. The results show that the plastic deformation mode changes from the plate-like stress-induced ω phase transformation with a special habit plane of {− 5052}ω//{3 − 3 − 2}β to {332}<113> type deformation twinning with increasing the content of vanadium in the β Ti-16-22 wt.% V alloys. The plate-like stress-induced ω phase has a special orientation relationship with the β phase matrix, i.e., [110]β//[− 12 − 10]ω, (3 − 3 − 2)β//(− 5052)ω and (− 55 − 4)β//(30 − 31)ω. The alloys plastically deformed by stress-induced ω phase transformation exhibit relatively higher yield strength than those deformed via {332}<113> type deformation twinning. It can be concluded that the stability of β phase plays a significant role in plastic deformation mode, i.e., stress-induced ω phase transformation or {332}<113> type deformation twinning, which governs the mechanical property of the β Ti-16-22 wt.% V alloys.