Modeling of dynamic recrystallization of magnesium alloy using cellular automata considering initial topology of grains

A two-dimensional cellular automaton (CA) model was established on MATLAB platform for quantitative and topographic simulation of the microstructure evolution of magnesium alloy ZM21 during hot deformation. A probabilistic approach was employed to improve the grain topology accuracy of discrete simulation method. Not only the average grain size but also more details including the grain size distribution of the measured microstructure were reflected in the initial conditions of CA simulation. Quantitative relationship between the parameters defined in the CA model and actual deformation condition was built to increase the applicability of the established model. The dynamic recrystallization (DRX) of magnesium alloy ZM21 was predicted using the CA model. Simulation results, including grain topology, average grain size, grain size distribution and DRX fraction were obtained and compared with experimental results. The good agreement between simulated and experimental results indicated that the established CA model is reliable to predict the microstructure evolution during the hot deformation of magnesium alloy. The influences of initial grain size and its distribution on the microstructure evolution were investigated. It indicated that fine and homogeneous microstructure at initial stage is favorable for the DRX process in hot deformation of magnesium alloy.