Dynamic recrystallization behavior and hot workability of AZ41M magnesium alloy during hot deformation

Abstract

The dynamic recrystallization (DRX) behavior and hot workability of AZ41M magnesium alloy were studied via isothermal compression experiments. The tests were performed at 300–450 °C with strain rate of 0.005–1 s−1 on a Gleeble-1500D thermal-mechanical simulation machine. According to the experimental results, the flow stress curves show a quintessential single-peak dynamic recrystallization behavior. The characteristic points of the flow stress curves including the critical strain of DRX initiation (εc) and the strain for maximum softening rate (ε*) were determined by employing the method of strain hardening rate analysis. Then the DRX kinetic model of AZ41M magnesium alloy was established by Avrami equation to characterize the evolution of DRX volume fraction. Furthermore, the processing maps at different strains were developed and analyzed based on dynamic material model (DMM). According to the processing maps, the flow instability regions and stability regions were identified. And the optimum domain for hot working of AZ41M magnesium alloy is the temperature range of 390–450 °C and strain rate range of 0.005–0.015 s−1.