ZK60镁合金高压扭转模拟及实验研究

Finite element simulation and experimental study on ZK60 magnesium alloy by high pressure torsion

为了研究高压扭转工艺对ZK60镁合金组织及性能的影响,采用有限元法对ZK60镁合金试样高压扭转成形过程进行数值模拟,分析成形过程中等效应力、应变分布及变化趋势。通过压扭设备和专用模具对镁合金试样进行高压扭转实验,采用金相显微镜观察试样的显微组织,利用维氏硬度计测量试样的显微硬度。结果表明:高压扭转能有效细化晶粒,改善材料组织结构;在一定的压力下,随着压扭圈数增加,晶粒得到细化,整体显微硬度有较大的提高;高压扭转后试样的显微硬度沿试样径向呈V型分布,与有限元模拟中试样径向的等效应变分布趋势一致。试样不同区域的等效应力、应变和显微硬度差异较大,边缘处的等效应力、应变最大,显微维氏硬度值最高。

In order to study the effect of high pressure torsion process on microstructure and properties of ZK60 magnesium alloy,the high pressure torsion（HPT） forming process of ZK60 magnesium alloy was simulated by finite element method,and the distribution and trend of equivalent stress and strain in the forming process were analyzed in detail. The high pressure torsion experiments of magnesium alloy specimens were carried out by special HPT equipment and dies,the microstructures of samples were observed by optical telescope and microhardness of the samples was measured by Vickers hardness tester. The results show that HPT can effectively refine grains and improve the organizational structure of the material; with the increase of torsion turns,grains are refined obviously and the microhardness of samples incrcuses greatly under certain pressure; the microhardness distributes in the V shape along the radial direction,which is consistent with the trend of the equivalent strain distribution in simulation results. The equivalent stress,strain and microhardness in different regions of the specimen are different,the equivalent stress,strain and Vickers hardness are the maximum at the edge.