电流加载方式对AZ31B镁合金板材拉伸变形行为的影响

Effect of electric current loading mode on tensile deformation behavior of AZ31B magnesium alloy sheet

为了探究脉冲电流加载方式对AZ31B镁合金板材拉伸变形行为的影响,通过单向拉伸实验研究了脉冲电流加载方式(持续加载与间断加载)和加载时间对AZ31B镁合金板材塑性的影响,结合试样温度场分布分析了电流辅助拉伸过程中试样宽度与厚度方向的应变分布,并观察了不同电脉冲电流参数条件下的微观组织。结果表明,脉冲电流间断加载能够有效提高材料塑性,降低变形抗力,在占空比为40%、电流加载时间为9 s条件下,AZ31B镁合金板材伸长率达到40.5%,并且发现在脉冲电流作用下,试样温度分布不均匀,从而导致了应变不均匀。此外,脉冲电流作用下AZ31B镁合金在较低温度下发生了不同程度的晶粒长大。

To investigate the effect of pulse current loading mode on the stretch deformation behavior of AZ31B magnesium alloy sheet,the uniaxial tensile test was conducted to study the effect of the pulse current loading mode(continuous loading and intermittent loading)and loading time on the plasticity of AZ31B magnesium alloy sheet.The strain distribution along the width and thickness directions of the sample during the current-assisted tensile process was analyzed combining with the temperature field distribution of the sample,and the microstructure under different pulse current loading parameters was observed.The results show that intermittently loading the pulse current can effectively improve the plasticity of the material and reduce deformation resistance.The elongation of AZ31B magnesium alloy sheet reaches 40.5%under the condition of duty ratio of 40%and loading time of 9 s.It is found that the temperature distribution of the sample is nonuniform under the action of pulse current,which leads to the nonuniform strain.In addition,under the action of the pulse current,AZ31B magnesium alloy has different degrees of grain growth at lower temperatures.