Twinning and dynamic recrystallization behaviors during inchoate deformation of pre-twinned AZ31 Mg alloy sheet at elevated temperatures

Abstract

To investigate the interrelation of dynamic recrystallization and detwinning behaviors, especially during the inchoate deformation stage at elevated temperatures, a commercial rolled AZ31 Mg alloy sheet is pre-twinned along the transverse direction to introduce {10−12} tensile twins, then the uniaxial stretch deformation is conducted. Results reveal that the detwinning dominates the microstructure evolution at room temperature, 100 °C, and 150 °C, while the dynamic recrystallization participates at temperatures of 200 °C and 250 °C. Further, the continuous dynamic recrystallization and detwinning accommodate the strain at 200 °C, while the discontinuous dynamic recrystallization suppresses the detwinning and predominates the deformation at 250 °C. Under different deformation temperatures, the interaction of dynamic recrystallization and detwinning exhibits different influences on the microstructure. Non-basal slips are activated at elevated temperatures, which affects the dynamic recrystallization behaviors and accommodates deformation strain. The texture evolution is closely related to the microstructure evolution mechanisms. The detwinning plays a hardening role in strength while dynamic recrystallization has a softening influence, the eventual effect on strength depends on the temperature.