中文摘要：

根据AZ31镁合金流动应力-应变曲线建立了材料模型,应用Deform-3D软件对AZ31镁合金薄壁管材反挤压过程进行了有限元模拟,分析了挤压过程中坯料和管材内部温度场、损伤因子及流动速率的分布情况,着重探讨了不同挤压温度、挤压速度和模角对最高温升、等效应力、流动速率及挤压力峰值的影响。结果表明,AZ31镁合金薄壁管材反挤压的最佳工艺参数：挤压温度为310℃、挤压速度为1mm/s、模角为60°。

英文摘要：

According to flow stress-strain curves of AZ31 magnesium alloy, the material model of AZ31 magnesium alloy was established, and the backward extrusion process of AZ31 magnesium alloy thinwall tubes was simulated by the Deform-3D software. The distribution of temperature field, damage factor and velocity of internal billet and tube were analyzed in extrusion process. Effects of extrusion temperature, extrusion speed and die angle on peak temperature, effective stress, velocity and maximum extrusion force were discussed. The results show that the optimized technological parameters such as extrusion temperature, extrusion speed and die angle of backward extrusion AZ31 magnesium alloy thinwall tubes reach 310 ℃, 1 mm/s and 60°, respectively.