Cellular automata coupled finite element simulation for dynamic recrystallization of extruded AZ80A magnesium alloy

The dynamic recrystallization (DRX) behavior of the extruded AZ80A magnesium alloy during plastic deformation was studied by coupling the physical-based finite element (FE) method and the developed cellular automata (CA) model. Isothermal compression tests were conducted by Gleeble-3800 thermal simulator at different temperatures of 598 K, 623 K, 648 K, 673 K, 698 K, and 723 K, and different strain rates of 0.001 s(-1), 0.01 s(-1), 0.1 s(-1), and 1 s(-1) to obtain the corresponding flow stress-strain curves. The constitutive model was established based on the analysis of the flow stress-strain curves. Moreover, parameters of the CA model were found. Based on the CA model, the DRX model was built. The established constitutive model and the DRX model were embedded in DEFORM-3D software to simulate the grain evolution under various deformation conditions. This combined method was capable of predicting the evolution of flow stress, DRX volume fraction, and DRX grain size in various deformation conditions. The results show that the error between the recrystallization volume fraction predicted by the finite element simulation and the CA model and the experimental results is less than 12.0%, and the error between the peak stress predicted by the CA model and the measured value remains within 8.0%. The prediction results of the combined methodology of the CA model and the FE simulation are consistent with the experimental results, which verify the usefulness and the prediction prospect of the coupled method. This method was probably a feasible choice to predict the DRX grain refinement of the thermal deformation process of the extruded AZ80A magnesium alloy.

Automated summary

The dynamic recrystallization (DRX) behavior of the extruded AZ80A magnesium alloy during plastic deformation was studied using the physical-based finite element (FE) method and the developed cellular automata (CA) model. Isothermal compression tests were conducted to obtain the flow stress-strain curves. A constitutive model and a DRX model were established based on the analysis of the experimental data. These models were embedded in DEFORM-3D software for simulation of the grain evolution. The combined method showed good prediction results and verified its potential.