Influencing factors of abnormal grain growth in Mg alloy by phase field method

Abstract

In this study, abnormal grain growth of single phase AZ31 Mg alloy was simulated by phase field modeling during the real spatiotemporal process. The influencing factors of abnormal grain growth were discussed to figure out ways for controlling secondary recrystallization in the microstructure evolution, as well as clarifying the mechanisms of abnormal grain growth in real alloys. The simulation revealed that abnormal grain growth was controlled by three key factors: strain restored energy, grain boundary energy, and grain boundary mobility. The grains with certain orientations in the microstructure with locally high restored energy, local low boundary energy or local high boundary mobility would induce secondary recrystallization after annealing treatment. However, no secondary recrystallization in the microstructure was generated at local restored energy E0’ with certain grain orientation ≤ 1.1E0, local boundary energy σ0’ ≥ 0.98σ0 or local boundary mobility L’ ≤ 2L.