Effects of Processing Parameters on Hot Deformation Behavior and Microstructure Evolution of As-cast AZ31B Magnesium Alloy

The effects of deformation temperature, strain rate and height reduction on hot deformation behavior and microstructure evolution of as-cast AZ31B magnesium alloy were researched in terms of hot compression tests. The results show that the peak stress decreases with the decreasing strain rate and increasing deformation temperature, and the main nucleation mechanism consists of initial grain boundary bulging nucleation, sub-grain rotation nucleation, twinning induced nucleation as well as continuous recrystallization. Moreover, the deformation temperature is below 400℃, the increase in temperature is beneficial to recrystallization and grain refinement, while above 400℃, grain size increases rapidly. Furthermore, the deformation temperature is equal to or lower than 400℃, the lower strain rate of 0.1 s-1 is more beneficial to the recrystallized grain refinement, while above 400℃, medium strain rate of 1 s-1 is more advantageous. In addition, it is found that at higher temperature and lower strain rate, height reduction primarily affects the grain size, and at higher temperature and higher strain rate, height reduction primarily affects the dynamic recrystallization degree. © 2019, Science Press. All right reserved.