Modeling of flow stress for magnesium alloy during hot deformation

Based on the classical flow stress–dislocation density relation and kinetics of dynamic recrystallization (DRX), a model was developed to determine flow stress of magnesium alloy at hot deformation condition. The proposed model is capable of predicting the flow behavior of work hardening and dynamic recovery (DRV) region as well as the softening caused by DRX. To establish the model, the double-differentiation method was used to identify the critical strain for initiation of DRX, and the DRV parameter Ω was evaluated from the work-hardening behavior prior to critical strain. The net softening attributable to DRX was defined as the difference between the DRV and experimental curves, and Avrami equation was employed to represent this softening behavior. The flow stress curves of ZK60 magnesium alloy predicted by the developed model are in good agreement with experimental results, which confirms the validity of the model.