Modeling of flow behavior and microstructure evolution for Mg-6Gd-5Y-0.3Zr alloy during hot deformation using a unified internal state variable method

Abstract

The hot deformation behavior of Mg-6Gd-5Y-0.3Zr alloy at the temperatures of 673–748K and the strain rates of 0.01–1.0s−1 were investigated by hot compression experiments. On this basis, a physically based internal state variable (ISV) model coupling the microstructural evolution was established, in which the ISVs of the model included dislocation density, grain size and volume fraction of dynamic recrystallization (DRX). Besides, the recrystallized and un-recrystallized grain sizes were considered to characterize the evolution process of microstructure. By comparing the calculated and experimental flow stresses, the model was proved to be reliable. Then the model was imported into the finite element analysis (FEA) software ABAQUS to predict the ISV evolution of Mg-6Gd-5Y-0.3Zr alloy in the hot extrusion process. The comparative analysis of the simulation and experimental results further verified the applicability of the constitutive model established in this study.