Stress-induced twinning and phase transformations during the compression of a Ti-10V-3Fe-3Al alloy

A metastable b Ti-10V-3Al-3Fe (wt.%) alloy containing different α phase fractions after thermo-mechanical processing was compressed to 0.4 strain. Detailed microstructure evaluation was carried out using high resolution scanning transmission electron microscopy and electron back-scattering diffraction. Stress-induced b → a′′ and b → ω transformation products together with {332}⟨113⟩b and {112}⟨111⟩b twinning systems were simultaneously detected. The effects of b phase stability and strain rate on the preferential activation of these reactions were analyzed. With an increase in b phase stability, stress-induced phase transformations were restricted and {112}⟨111⟩b twinning was dominant. Alternatively, less stable b conditions or higher strain rates resulted in the dominance of the {332}⟨113⟩b twinning system and formation of secondary a′′ martensite.