Stress-Induced α″ Martensitic Transformation Mechanism in Deformation Twinning of Metastable β-Type Ti-27Nb-0.5Ge Alloy under Tension

Abstract

In this study, the formation mechanism of the stress-induced α ′′ martensitic phase in the deformation twinning (DT) band of metastable β-type Ti-27Nb-0.5Ge (at.%) alloy under tension was investigated. A preferential nucleation site for the stress-induced α ′′ martensitic transformation is inside a DT band with high dislocation density. The α ′′ martensitic phase developed in the DT band with increasing applied plastic strain. The α ′′ martensitic phase subsequently grew to intersect other DT bands, forming secondary DT bands themselves in the parent β grains.

Transformations of the Microstructure and Phase Compositions of Titanium Alloys during Ultrasonic Impact Treatment Part II: Ti-6Al-4V Titanium Alloy

“…As a rule, the strain-induced βα" martensitic transformations are also observed in metastable β titanium alloys subjected to tempering followed by tension [35,36], compression [37] or torsion [38]. The development of the βα" transformations in the studied Ti-6Al-4V samples subjected to UIT is concerned with metastability of the retained β phase owing to the presence of oxygen.…”