锻压技术

挤压态镁合金热压缩微观组织预测模型

英文标题：Prediction model on microstructure for as-extruded magnesium alloy in thermal compression

作者：丁小凤蒯玉龙胡建华双远华

单位：太原科技大学

分类号：TG335.71

出版年,卷(期):页码：2022,47(2):199-206

摘要：

在变形温度为250~450 ℃、应变速率为0.005~5 s-1的条件下，采用热模拟压缩实验得到流动应力-应变曲线，研究了挤压态镁合金热变形和动态再结晶行为。结果表明：AZ31镁合金发生动态再结晶的临界应变随着变形温度的升高或应变速率的减小而降低；镁合金变形初期发生动态再结晶所需要的激活能为191.2 kJ·mol-1。基于实验数据回归分析，建立AZ31镁合金动态再结晶临界应变模型，得到动态再结晶临界应变与流动应力曲线峰值应变的比值约为0.57；应用Avrami方程建立镁合金动态再结晶动力学模型，预测出镁合金动态再结晶临界应变值，与微观组织实验结果一致，验证了模型的正确性，可以用于AZ31镁合金热加工中的动态再结晶预测。

Under the conditions of the deformation temperatures of 250-450 ℃ and the strain rates of 0.005-5 s-1, the flow stress-strain curves were obtained by thermal simulation compression experiment, and the thermal deformation and dynamic recrystallization behavior of as-extruded magnesium alloy were investigated. The results show that the critical strain of dynamic recrystallization for AZ31 magnesium alloy decreases with the increasing of deformation temperature or the decreasing of strain rate, and the activation energy required for dynamic recrystallization in the initial deformation of magnesium alloy is 191.2 kJ·mol-1. Based on the regression analysis of experimental data, the dynamic recrystallization critical strain model of AZ31 magnesium alloy was established, and the ratio of dynamic recrystallization critical strain to peak strain in the rheological flow stress curve was about 0.57. Furthermore, the dynamic recrystallization kinetics model of magnesium alloy was established by Avrami equation to predict the critical strain value of dynamic recrystallization for magnesium alloy, which was consistent with the results of microstructure experiments. Thus, the correctness of the model was verified, and the model could predict dynamic recrystallization in the hot working of AZ31 magnesium alloy.

基金项目：

山西省优秀来晋博士人员科研资助(20202002)；山西省高校科技创新项目(2019L0626)；太原科技大学科研启动金(20182043)；山西省科技重大专项(20191102009)

作者简介：丁小凤（1987-），女，博士，副教授，E-mail：dingxiaofeng@tyust.edu.cn

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