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

Abstract

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–16–22wt.% 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–16–22wt.% V alloys.