This study systematically discussed the high-temperature flow behavior of the
Mg-Al-Zn based AZ91 alloy, which has significant application potential in modern
aviation and automotive industries. The study was carried out in the temperature
range of 250°C-450°C and the strain rate range of 0.001 s^−1 -0.1
s^−1, which met the typical industrial hot processing environment.
The analysis of high-temperature flow behavior shows that the flow stress is
inversely proportional to the deformation temperature and is proportional to the
strain rate. An important finding is that the constitutive model parameters are
significantly sensitive to strain, so the strain-compensated Arrhenius
constitutive model is developed. The model shows high accuracy in predicting the
thermal flow stress of AZ91, and provides a valuable calculation tool for the
simulation and optimization of forming processes in aerospace parts
manufacturing. The results show that the extruded original microstructure
presents slender fine grains, while the deformed sample shows a temperature
dependent transformation: the low-temperature bimodal structure evolves into
uniform fine grains at intermediate temperature, and the grains begin to coarsen
at high temperature. At constant high temperature, low strain rate promotes
grain growth and twin formation, while high strain rate refines grains and
inhibits twins, and dislocation slip is the dominant deformation mechanism.
These findings provide vital guidance and support for optimizing hot working
parameters of AZ91, and are particularly important for manufacturing lightweight
components in aircraft structures and automotive systems. The established
process performance relationship is helpful to develop energy-saving
manufacturing strategies for transportation equipment, and supports the goal of
reducing weight and improving performance in the industrial field.