Formation mechanism of texture during dynamic recrystallization in γ-TiAl, nickel and copper examined by microstructure observation and grain boundary analysis based on local orientation measurements

Texture formation in γ-TiAl, nickel and copper during dynamic recrystallization (DRX) in compression deformation is studied. The formation process is discussed in relation to the mechanism of new grain formation during DRX. It is found that the behavior of texture formation varies depending on Z (the value of the Zener-Hollomon parameter) and the kind of material. During deformation in low Z conditions, sharp fiber texture develops in γ-TiAl, suggesting that strain-induced grain boundary migration is predominant in the new grain formation. No sharp texture is seen in nickel and copper after the dynamic recrystallization in low Z conditions. However, microstructure observation suggests that new grains are also generated by strain-induced grain boundary migration in these two pure metals. It is found that the difference of texture formation between γ-TiAl and the other two pure metals is ascribed to the difference in the frequency of twinning during grain boundary migration; texture develops only when the frequency is low, which is the case of γ-TiAl.