Hot compression deformation behavior and microstructure evolution of Al-0.5Mg-0.4Si alloy

Abstract

The hot compression tests for as-cast Al-0.5Mg-0.4Si alloy were performed on Gleeble-3500 thermo-mechanical simulator under temperatures of 350–500 °C and strain rates of 0.01–10 s−1. Based on the experimental data, a strain-compensated Arrhenius constitutive model was established by exponential function coupling strain. The hot processing map of Al-0.5Mg-0.4Si alloy was established, and the reasonable processing parameters were obtained. The microstructural evolution and dynamic softening mechanisms of the alloy were analyzed using electron backscatter diffraction (EBSD). A detailed description of the evolution of dislocation and the dislocation density during the deformation process was provided. The results indicate that the softening mechanisms of Al-0.5Mg-0.4Si alloy are dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX). The dynamic recovery mechanism is related to the cross slip of the screw dislocation. High temperature and low strain rate are conducive the occurrence of CDRX. This study provides comprehensive guidance for the hot processing of Al-0.5Mg-0.4Si alloy from both macroscopic and microscopic perspectives.