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通过单向拉伸试验研究镁合金AZ31B的电塑性效应。为了显示脉冲电流的非热效应,在相同温度下开展两类试验:环境箱中的单向拉伸试验和脉冲电流辅助的单向拉伸试验。此外,对脉冲电流在材料变形过程中引起的温度场进行数值模拟。结果表明,沿材料截面方向温度分布均匀。通过对比两类单向拉伸试验的真应力-真应变曲线,证实了脉冲电流非热效应的存在。通过光学显微镜研究脉冲电流对材料微观组织演化的影响,结果表明:脉冲电流引起的动态再结晶对流动应力的下降起重要作用。最后,提出一个考虑电塑性响应的AZ31B流动应力模型,并通过实验进行验证。结果表明:模型预测结果和实验结果吻合较好。
Electro-plastic effect of AZ31B magnesium alloy was studied by uniaxial tensile test. To show the non-thermal effects of pulsed currents, two types of tests were carried out at the same temperature: a unidirectional tensile test in an environmental chamber and a pulse-current-assisted unidirectional tensile test. In addition, the numerical simulation of the temperature field caused by the pulse current in the process of material deformation is carried out. The results show that the temperature distribution along the material cross-section direction is uniform. By comparing the true stress-strain curves of two types of uniaxial tensile test, the existence of non-thermal effect of pulse current is confirmed. The effect of pulse current on microstructure evolution was studied by optical microscope. The results show that the dynamic recrystallization caused by pulse current plays an important role in the decrease of flow stress. Finally, a flow stress model of AZ31B considering the electrical and plastic response is proposed and verified by experiments. The results show that the model predictions agree well with the experimental results.