Microstructural Characteristics and Subsequent Soften Mechanical Response in Transverse Direction of Wrought AZ31 with Elevated Compression Temperature

In order to investigate the effect of temperature on the microstructure evolution and mechanical response in the transverse direction of a wrought AZ31 (AZ31-TD) alloy under a high strain rate, the dynamic compression was conducted using Split Hopkinson Pressure Bar (SHPB) apparatus and a resistance-heated furnace under 1000 s(-1) at 20-250 degrees C. By combining optical and EBSD observations, the microstructure's evolution was specifically analyzed. With the help of theoretically calculated Schmid Factors (SF) and Critical Resolved Shear Stress (CRSS), the activation and development deformation mechanisms are systematically discussed in the current study. The results demonstrated that the stress-strain curves are converted from a sigmoidal curve to a concave-down curve, which is caused by the preferentially and main deformation mechanism {101 over bar 2} tension twinning gradually converting to simultaneously exist with the deformation mechanism of a non-basal slip at an elevated temperature, then completing with each other. Finally, the dynamic recrystallization (DRX) and non-basal slip are largely activated and enhanced by temperature elevated to weaken the {101 over bar 2} tension twinning.

Automated summary

This study investigated the effect of temperature on microstructure evolution and mechanical response in a wrought AZ31 alloy under high strain rates. The results showed that at elevated temperatures, stress-strain curves transition from a sigmoidal shape to concave-down, due to the transition of {101 over bar 2} tension twinning to coexist with non-basal slip. Dynamic recrystallization and non-basal slip mechanisms were found to be activated and enhanced at higher temperatures, weakening the {101 over bar 2} tension twinning.