FEM simulation of micro-crystalline materials during ECAP based on the dislocation evolution method

Abstract

Based on severe plastic deformation, the equal channel angular pressing (ECAP) method has been used for producing metal materials with the ultrafine grain size and specific mechanical properties, particularly high yield strength. The grain sizes and the mechanical properties of ECAP processed materials strongly depend on the degree of plastic deformation, which is congregated by the evolution of dislocation slipping in the slipping planes. It is very important to analyze the dislocation density and strain hardening evolution in the slipping planes. In this paper, based on the crystal plastic model, the strain hardening & grain refinement of aluminum alloys were calculated with a dislocation evolution model during equal channel angular pressing. Next, the simulated strain, stress and grain size evolution were analyzed. Although the maximum value of the strain is very similar, the stress is rapidly increased when the materials pass the shear areas. Regarding the congregation of the dislocation density, the grain sizes decrease with the process continuing.