镁合金AZ31D的热变形力学行为与微观组织演化规律的试验研究

Hot Forming Behavior and Microstructure Evolution of Magnesium Alloy AZ31D

对具有粗大柱状晶的镁合金AZ31D材料进行了圆柱体热压缩试验研究。通过试验获得了该种材料在不同温度、不同应变速率条件下的真应力-应变曲线以及动态再结晶和晶粒细化的规律。应用峰值应力的试验结果计算出了该材料热变形过程的激活能及试验条件下的Z参数,得到了镁合金AZ31D的热变形过程以及动态再结晶过程的主要特征变量作为Z参数的函数表达式。试验发现,当Z≥(2.61E+6)s-1时,热压缩试验过程中会出现与试样端面成45°角的剪切断裂。

An experimental study on hot compression deformation of cylindrical specimen of magnesium alloy AZ31D with coarse columnar grains was conducted. The experimental results include the true stress-strain curves under different temperature and different strain rate, the data on dynamic recrystallization process and grain refinement. By using the experimental data on peak stress, the activation energy of the hot deformation is obtained, and then the Zener-Hollomon parameters corresponding to different experimental conditions are also obtained. The mathematic expressions of the variables describing hot deformation and microstructure evolution, as the function of the Z parameter, are given. In the experiments it is also observed that a shear fracture with angle 45° to the specimen end surface appears when Z≥ （2.61E ＋6）s^-1.