Dynamic recrystallization kinetics of as-cast AZ91D alloy
(1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. School of Mechanical Engineering, Beihua University, Jilin 132021, China)
2. School of Mechanical Engineering, Beihua University, Jilin 132021, China)
Abstract: The flow behavior and dynamic recrystallization (DRX) behavior of an as-cast AZ91D alloy were investigated systematically by applying the isothermal compression tests in temperature range of 220-380 °C and strain rate range of 0.001-1 s-1. The effect of temperature and strain rate on the DRX behavior was discussed. The results indicate that the nucleation and growth of dynamic recrystallized grains easily occur at higher temperatures and lower strain rates. To evaluate the evolution of dynamic recrystallization, the DRX kinetics model was proposed based on the experimental data of true stress-true strain curves. It was revealed that the volume fraction of dynamic recrystallized grains increased with increasing strain in terms of S-curves. A good agreement between the proposed DRX kinetics model and microstructure observation results validates the accuracy of DRX kinetics model for AZ91D alloy.
Key words: AZ91D magnesium alloy; compression; flow behavior; dynamic recrystallization behavior; kinetics model