Microstructure Evolution in a β-γ TiAl Alloy during Hot Deformation under Variable Conditions

In contrast to practical hot compression processes, the testing of workability TiAl alloys is usually conducted under conditions constant strain rates and temperatures. This work aims at investigating microstructural evolution on a Gleeble-3800 thermomechanical simulator variable rate (0.1, 0.01 0.001 s−1) 1200 °C. The results show that, after holding time 30 s, abrupt change in ε = 0.3 (engineering strain) has remarkable influence flow stress dynamic recrystallization (DRX) behavior β-γ Ti-44Al-6Nb-1Mo-0.3 (B, Y, La, Ce) (at.%) alloy. demonstrates rapid decrease with sudden reduction rate. A duplex microstructure γ + B2/β can be obtained high or continuous medium During two-step deformation, however, both γ→α phase transformation DRX exist, content α significant increase when becomes lower. Finally, fine-grained structure α2 phases low residual stresses via heat treatment processes. provides promising approach significantly improve alloys.