A novel simulation of continuous dynamic recrystallization process for 2219 aluminium alloy using cellular automata technique

Abstract

Based on the previous experiments, continuous dynamic recrystallization (CDRX) was determined to be the main softening mechanism of Al 2219 alloy during the thermal deformation process. The mechanism of microstructural transformation for the CDRX process was firstly discussed, and the dislocation evolution model, subgrain growth nucleation model, low angle grain boundaries (LAGBs) migration model, and topological deformation model were established respectively. Using the probabilistic cellular automata technique, a two-step microstructure formation method of initial equiaxed grains + local subgrains dispersion was proposed, which can simulate the initial microstructure at any processing state. Then, according to the proposed micro-mechanism and models of CDRX, a novel simulation approach of the CDRX process for Al 2219 alloy during thermal processing was established on the Matlab platform to predict the substructure's evolution. The CA model was applied to extensively analyze the influence of deformation parameters and the transformation law of LAGBs. The results showed that high temperature, high strain, and low strain rate can effectively promote the development of continuous dynamic recrystallization, which is consistent with the experimental results.