A cellular automaton coupled FEA model for hot deformation behavior of AZ61 magnesium alloys

The microstructure evolution and dynamic recrystallization (DRX) behavior of AZ61 alloy during hot deformation were investigated by hot compression experiments and numerical simulation based on finite element method (FEM) and cellular automaton (CA). Through the hot compression tests, the hot deformation behavior of AZ61 alloy was analyzed over a range of temperatures (375, 400, 425, 450 °C) and strain rates (0.001, 0.01, 0.1, 1 s−1), and the corresponding flow stress curves were obtained. According to the experimental results, a physically-based constitutive model considering the stress-dislocation relationship was established. The comparison between the experimental and predicted flow stresses verified the reliability of the established model. Moreover, the physically-based constitutive model was incorporated into the FE software ABAQUS to simulate the microstructure evolution of AZ61 alloy during the hot compression process. Both the FE simulation and experimental results indicated the microstructure inhomogeneity in the compression specimen. In order to describe the microstructure evolution of AZ61 alloy during hot deformation more precisely, a modified cellular automaton (CA) model considering the varying strain rate was developed based on the obtained material kinetic model. The CA simulation results were in good accordance with the experimental ones, indicating the FEM & CA simulation which incorporated the physical based constitutive relationship was reliable to reliably predict the DRX behavior and microstructure evolution of AZ61 alloy in the hot deformation process.