中文摘要：

在变形温度250~450℃、应变速率0.005~5 s-1下对铸态AZ31B镁合金圆柱试样进行了Gleeble高温压缩实验。对不同初轧温度、不同轧制压下量下镁合金的热轧制过程进行了实验、数值模拟及损伤分析。采用动态材料模型中的计算方法计算了热加工图,用Zener-Hollomon参数法建立了单向压缩时的流变应力模型,最后综合传热学基本原理及轧制理论,建立了变温轧制过程中的流变应力模型。研究结果表明：合理分解温度范围求解单向压缩流变应力模型,有效提高了模型的预测精度;轧制前滑区和后滑区的主传热机制有所区别,考虑到轧辊对轧件的作用力主要分布在后滑区,则此区域为边裂重点研究区域;数值模拟过程中轧件边部区域的Normalized Cockcraft and Latham损伤值最大,并且随着变形温度的降低以及道次压下量的增大而增大。此现象与轧制实验结果相符,不同轧制条件下轧制流变应力模型的求解结果与数值模拟结果较吻合。

英文摘要：

Compression tests were performed at the temperatures ranging from 250 °C to 450 °C and strain-rates from 0.005 s-1 to 5 s-1. The rolling test, numerical simulation and damage analysis were conducted. The thermal processing diagram was calculated by the dynamic material model. A material flow stress model was established by the parameter method of Zener-Hollomon. Combined with the principle of heat transfer and rolling theory, the rheological stress model of hot rolling process was established. The results show that the model in reasonable temperature range to solve, effectively improves the prediction accuracy. The main heat transfer mechanisms in forward slip area and backward slip area are different and the rolling force is mainly distributed in backward slip area, which is the key research area of edge crack. In the rolling process, Normalized C-L damage value is maximum on sheet edge. The lower the deformation temperature and the more pass reduction, the greater the value of damage, which is consistent with the outcome of the rolling experiment. Under different rolling conditions, the results of the model solution are consistent with the numerical simulation of hot rolling process.