Prediction of hardness distribution during SPD process based on FEM simulations: case study of ECAP and HPT processes

Abstract

3D finite element method (3D FEM) simulations of equal channel angular pressing (ECAP) and high-pressure torsion (HPT) of Al6061-T6 alloy were carried out and analyzed. 3D FEM results were correlated and compared with those obtained experimentally and theoretically through different mathematical equations. Furthermore, the hardness was estimated using the FEM strain and theoretical strain. The simulations and experimental results were in high conformity with each other. The ECAP load−displacement curves, the HPT load-time curves, and peak loads of FEM and experimental results were close to each other. FEM simulations provided clear strain distribution maps in different planes that fully explain the plastic deformation characteristics and homogeneity in the ECAP and HPT processes. FEM effective strain results have high reliability with a slight deviation from those theoretically estimated through the mathematical equations. The hardness distribution and the strain contours maps were in good agreement, confirming the quality of the FEM results. Hardness values calculated based on FEM effective strain indicate a deviation range of 0.96%–8.8% from experimental results that support the reliability of the FEM results. Microstructure results support hardness increase because of the effect of the grain refinement after ECAP and HPT processing.