Stress-induced phase transformations in Ti-15Mo alloy at elevated temperature

Controlled mechanical loading was applied to Ti-15Mo alloy during annealing at 550 ${}^{\circ }$C. Massive formation of the ${\omega }_{\text{iso}}$ phase from the parent $\beta$-phase occurred during annealing at 550 ${}^{\circ }$C without external stress or with stress well below the yield stress. Moreover, a massive $\alpha$ phase precipitation takes place under simultaneous annealing and plastic deformation. Plastic deformation plays a key role in $\beta \to \alpha$ transformation and achieving refined $\alpha +\beta$ type microstructure resulted in improved mechanical properties. Studying phase transformations during plastic deformation is critical for understanding and optimizing thermomechanical processing of metastable $\beta$-Ti alloys.