Constitutive equation and microstructure evolution of TiAl alloy during hot deformation

Abstract The hot deformation behavior of TiAl alloy is analyzed by combining the true stress–strain curve and microstructure analysis. The results show that the flow stress of TiAl alloy presents the characteristics of work hardening-dynamic softening, it increases with the increase of strain rate and decreases with the increase of temperature. Based on the true stress–strain curves, the flow stress of TiAl alloy under different deformation conditions is predicted by hyperbolic sinusoidal formula. In addition, the effects of deformation temperature and strain rate on the microstructure evolution of TiAl alloy are revealed. In the process of hot compression deformation, dynamic recrystallization and γ → α , β → α phase transformation occurs. During tensile deformation, TiAl alloy exhibits super-plasticity, which is mainly due to grain rotation and coordinated deformation of β phase.