Effect of Severe Plastic Deformation on the Microstructure Evolution of AZ31 Magnesium Alloys

Equal channel angular extrusion (ECAE) process has the capability to proddce bulk nonstructural materials without loose holes. Using commercial metal forming finite element code, ECAE process was analyzed numerically in the present research. It combined the node reflection method and three-dimensional model switching to realize multi-extrusion process of Routes A, Ba, Bc and C by the finite element method. The distribution of accumulated effective strain and the influence rules of deformation uniformity in round billets were obtained, and the grain refining mechanism of equal channel angular multi-extrusion for different processing routes was given. The results show that changing the extrusion route can alter the microstructure of the workpiece, which can be gradually refined in each route with the number of extrusion increasing. It is found that route Bc and C can get larger angle grain boundaries and more uniform equiaxed grain distribution than other routes. In addition, the microstructure evolutions of different multi-pass ECAE processing routes are consistent with FE analyses.