A New Dynamic Recrystallization Kinetics Model of Cast-Homogenized Magnesium Alloys

Dynamic recrystallization always occurs during hot forming of magnesium alloys and largely controls their microstructure evolution. In this study, we developed a new dynamic recrystallization kinetics model with one undetermined parameter based on isothermal compression tests of a cast-homogenized Mg-8Gd-3Y alloy (GW83) at temperatures ranging from 300 °C to 450 °C and strain rates from 0.001 to 0.1 s−1, and measured its dynamic recrystallization volume fractions. The undetermined parameter could be determined by parameter regression. The adaptability of the new model was further examined by comparison with the published data of isothermal compression experiments of AZ31B and ZK60 alloys. The predicted results were well consistent with the experimental results. By integrating the new model with finite element software, we investigated the dynamic recrystallization kinetics of upsetting and plane strain forging of GW83 alloy. The predicted distributions of the dynamic recrystallization volume fraction agreed very well with the experimental values under four different sets of isothermal deformation conditions. These results indicated that the new dynamic recrystallization kinetics model affords highly accurate predictions of the kinetics of cast-homogenized magnesium alloys.