Deformation behavior and dynamic recrystallization mechanism of a novel high Nb containing TiAl alloy in (α + γ) dual-phase field

Abstract

Dynamic recrystallization (DRX), microstructure evolution and texture of high Nb containing TiAl alloys with a composition of Ti-43Al-6Nb-1Mo-1Cr (at.%) during the isothermal deformation are investigated in this paper. The recrystallized γ grains with L10 structure dominate the deformation in condition 1150°C/0.005 s-1. Meanwhile, the deformation-induced γ/α2→α phase transformation occurs in present TiAl alloy. Except the continuous dynamic recrystallization (CDRX) characterized by crystal orientation accumulation, lots of grains with specific 89±3° misorientation angles related to discontinuous dynamic recrystallization (DDRX) are observed in the γ phase. The specific misorientation angles might be caused by grains rotation, which is related to the activation of {111}<110> slipping system in γ phase. As regards as texture, the texture of α2 phase mainly maintains transverse texture during the deformation. And γ phase exhibits typical hot-rolled texture at low strain. With the strain increasing to 40%, the scattered texture appears, due to the nucleation of many dynamic recrystallized grains. The variety of texture is mainly caused by different DRX behaviors at various strains.