Hot deformation behavior of AZ91 magnesium alloy in temperature ranging from 350°C to 425°C

The flow behavior and microstructure evolution of AZ91 magnesium alloy during a thermomechanical process, hot compression test, was investigated. The specimens were hot compressed at a temperature ranging from 350°C to 425°C and at strain rate of 0.1 s−1 to the strains of 0.3, 0.5 and peak. Microstructural evolutions were studied using optical and scanning electron microscopes. The results show that during the compression process, the recrystallized grains nucleate along the pre-existing grain boundaries. The amount of dynamically recrystallized grains is increased with strain in a sigmoid scheme followed by Avrami equation. The size of dynamically recrystallized grains also increases at the beginning and decreases after reaching the maximum value.