Deformation behaviour of retained β phase inβ-eutectoid Ti-Cr alloys

Abstract

Plastic deformation mode and its relation to tensile properties were investigated in retainedβ phase ofβ-eutectoid type Ti-Cr alloys. A plate-like single variantω phase is induced during deformation of the most unstableβ phase having a minimum chromium content required to suppress martensitic transformation. A selected area electron diffraction pattern taken from a boundary region of the stress-inducedω phase plate can be explained by the idea that a single variant ofω phase is induced in a {3 3 2} 〈1 1 3〉 twin produced during deformation. Anisotropy in population of fourω phase variants decreases with increasing chromium content. On further increasing chromium content, deformation occurs by slip. Enhanced ductility is obtained in as-quenched Ti-Cr alloys accompanied byω phase transformation or {332} 〈1 1 3〉 twinning during deformation,ω phase of as-quenched Ti-Cr alloys changes continuously from commensurate structure with sharp reflections to incommensurate structure with diffuse reflections with increasing chromium content. The obtained results inβ-eutectoid type Ti-Cr alloys are quite similar to those inβ-isomorphous type Ti-V alloys.