In this paper, a unified internal state variable (ISV) model for predicting microstructure evolution during hot working process of AZ80 magnesium alloy was developed. A novel aspect of the proposed model is that the interactive effects of material hardening, recovery and dynamic recrystallization (DRX) on the characteristic deformation behavior were considered by incorporating the evolution laws of viscoplastic flow, dislocation activities, DRX nucleation and boundary migration in a coupled manner. The model parameters were calibrated based on the experimental data analysis and genetic algorithm (GA) based objective optimization. The predicted flow stress, DRX fraction and average grain size match well with experimental results. The proposed model was embedded in the finite element (FE) software DEFORM-3D via user defined subroutine to simulate the hot compression and equal channel angular extrusion (ECAE) processes. The heterogeneous microstructure distributions at different deformation zones and the dislocation density evolution with competitive deformation mechanisms were captured. This study can provide a theoretical solution for the hot working problems of magnesium alloy.

本文开发了一个统一的内部状态变量 (ISV) 模型，用于预测 AZ80 镁合金热加工过程中的组织演变。所提出模型的一个新方面是，通过将粘塑性流动、位错活动、DRX 成核和边界迁移的演化规律结合到耦合中，考虑了材料硬化、恢复和动态再结晶 (DRX) 对特征变形行为的交互影响。方式。基于实验数据分析和基于遗传算法（GA）的目标优化校准模型参数。预测的流变应力、DRX 分数和平均晶粒尺寸与实验结果吻合良好。所提出的模型通过用户定义的子程序嵌入到有限元 (FE) 软件 DEFORM-3D 中，以模拟热压缩和等通道角挤压 (ECAE) 过程。捕获了不同变形区的异质微观结构分布和具有竞争变形机制的位错密度演变。本研究可为镁合金的热加工问题提供理论解决方案。