摘要
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。
Microstructures and phase compositions of as-cast and heat treated ZK60-xOa magnesium alloys were analyzed by OM, SEM, XRD and DSC. The hardness and tensile property at ambient temperature were tested. The results show that the as-cast microstructure is refined gradually with increasing Ca content. A new phase, Mg6Zn3Ca2, is formed. The phases precipitated along grain boundary increase gradually and distribute in continuous reticulation. The hardness increases gradually, while the corresponding tensile strength and elongation decreases gradually. Majority of MgZn2 phase dissolves into a-Mg matrix, while only a little of Mg6Zn3Oa2 phase does. Tensile properties of ZK60 and ZK60-1.25Ca alloys increase obviously after solution at 648 K, and gradually decrease with increasing solution temperature. After aging at 448 K, the tensile and yield strength increase for the former alloy, while the tensile strength unchanges for the latter alloy. The elongation decreases for the two alloys.
出处
《铸造技术》
CAS
北大核心
2011年第12期1712-1717,共6页
Foundry Technology
基金
广东省产学研重大项目资助(2010A090200078)
关键词
ZK60镁合金
Ca变质
显微组织
力学性能
ZK60 magnesium alloy
Ca modification
Microstructure
Mechanical property
