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利用光镜、扫描电镜、XRD和DSC,分析了铸态和热处理态ZK60-xCa合金的组织和相组成,测试了其硬度和室温拉伸性能。结果表明,随着Ca含量的增加,铸态组织逐渐细化,生成Mg6Zn3Ca2新相,晶界相逐渐增多,且趋于连续网状分布;硬度逐渐提高,而抗拉强度和伸长率逐渐降低。MgZn2相绝大多数固溶于α-Mg基体中,而Mg6Zn3Ca2相少量固溶。ZK60和ZK60-1.25Ca合金拉伸性能经648K固溶后均显著提高,随固溶温度的提高而逐渐降低;经448K时效后,前者的抗拉和屈服强度有所提高,后者的抗拉强度不变,两者的伸长率均降低。
Microstructure and phase composition of as-cast and heat-treated ZK60-xCa alloy were analyzed by light microscopy, scanning electron microscopy, XRD and DSC. The hardness and room temperature tensile properties were tested. The results show that with the increase of Ca content, the as-cast microstructure is gradually refined and a new phase of Mg6Zn3Ca2 is formed. The grain boundary phase gradually increases and tends to be continuously reticulated distribution. The hardness gradually increases while the tensile strength and elongation decrease. The vast majority of MgZn2 phase solid solution in the α-Mg matrix, and a small amount of Mg6Zn3Ca2 phase solution. Tensile properties of ZK60 and ZK60-1.25Ca alloy increased significantly after solid solution treatment at 648K and gradually decreased with the increase of solution temperature. Tensile strength and yield strength of ZK60 and ZK60-1.25Ca alloy increased after aging at 448K, Strength unchanged, both the elongation decreased.