添加Ca和Sr元素对ZK61镁合金组织与性能的影响

利用光学显微镜、X射线衍射仪、扫描电镜、Vickers硬度计及拉伸试验机等观察并研究了添加Ca和Sr元素及热处理工艺对ZK61镁合金组织和力学性能的影响。结果表明:单独添加Ca元素时,在ZK61-xCa合金α-Mg基体上析出了形状不规则的MgZn和MgZn2相;复合添加Ca、Sr元素时,在α-Mg基体上形成了沿晶界分布的Mg17Sr2新相。当固溶温度和时间为350℃×12 h,时效温度和时间为200℃×12 h时,合金的组织与性能达到最优。当元素Ca=1.0%,Sr=0.5%时,热处理后合金的性能最优,其抗拉强度为141.9 MPa,伸长率为15.6%,维氏硬度为51.6 HV。

Effect of adding Ca and Sr elements on microstructure and properties of ZK61 magnesium alloy

Effects of adding Ca and Sr elements and heat treatment on microstructure and mechanical properties of ZK61 magnesium alloy were studied by means of optical microscope,X-ray diffractometer,scanning electron microscopy,Vickers hardness tester and tensile testing machine.The results show that the irregular MgZn and MgZn2 phases precipitate on theα-Mg matrix of the ZK61-xCa alloys when the Ca element is added,and the Mg17Sr2phase along the grain boundary is formed on theα-Mg matrix of the ZK61-xCa-ySr alloys when the Ca and Sr elements are added.The microstructure and the performance of the alloys reach the optimal after solid solution treatment at 350℃for 12 h and then aging at 200℃for 12 h.When the content of Ca and Sr is 1.0%and 0.5%,respectively,the properties of the alloy after heat treatment are the best,which the tensile strength is 141.9 MPa,the elongation is 15.6%,and the Vickers hardness is 51.6 HV.