Effect of grain size on tensile properties of fine-grained metastable β titanium alloys fabricated by stress-induced martensite and its reverse transformations

Fine-grained Ti-16V-3.5Al-3Sn alloys were fabricated through the stress-induced martensite and its reverse transformations. All tensile curves of the alloys showed double yielding, high strain hardening and low trigger stress for martensitic transformation. As the grain size increased, the trigger stress decreased and then increased again, while the dimples on the fractured surface became large and non-uniform. The three-stage strain hardening and high strain-hardening rate were closely associated with the stress-induced β to α″ martensitic transformation and dislocation hardening.