等通道挤压Mg2Si增强ZK60镁合金的显微组织及力学性能.docVIP

 等通道挤压 Mg2Si 增强 ZK60 镁合金的显微 组织及力学性能# 贾俊豪，梁伟，韩富银，王红霞** 5 10 （太原理工大学材料科学与工程学院，太原 030024） 摘要：研究了等通道挤压(ECAP)对 ZK60+2Si 镁合金显微组织、室温力学性能和高温抗蠕变 性能的影响。结果表明，合金铸态组织主要由 a-Mg 基体、Mg2Si 相和 MgZn 相组成，等通 道挤压可显著碎化原粗大汉字状 Mg2Si 相并使其趋于弥散分布，同时基体组织也得到细化。 挤压 4 道次后，合金的室温抗拉强度由 154.8MPa 增加到 270MPa，伸长率由 4.5%增加到 17.5%。挤压 6 道次后，合金的伸长率进一步增加到 21%，而抗拉强度却下降至 261MPa； 合金的高温蠕变寿命由铸态 20h 延长到 203h，稳态蠕变速率下降了约一个数量级，这主要 是因为细小颗粒状 Mg2Si 相有效阻止了晶界滑移。 关键词：镁合金；显微组织；力学性能；等通道挤压；蠕变 中图分类号：TG146.2 15 Study on microstructure and mechanical properties of Mg2Si reinforced ZK60 magnesium alloy deformed by ECAP JIA Junhao, LIANG Wei, HAN Fuyin, WANG Hongxia 20 25 30 35 40 (College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024) Abstract: The effects of Equal Channel Angular Pressing(ECAP) on microstructure, mechanical properties at room temperature and high-temperature creep resistance of ZK60+2Si alloy were investigated. Experimental results show that, the components of as-cast alloy are mainly 　-Mg matrix, Mg2Si and MgZn phases. In the process of ECAP, the original coarse Chinese-script Mg2Si phase are significantly broken into particles which tend to diffuse distribution, and the matrix is also been refined. After 4 passes of EACP, the tensile strength and elongation of alloy at room temperature increases from 154.8MPa, 4.5% to 270MPa, 17.5% respectively. After 6 passes of EACP, elongation further increases to 21%, however, tensile strength drops to 261MPa. The high-temperature creep life of alloy is extended from 20h to 203h, and steady creep rate decrease an order of magnitude. It is mainly because the tiny Mg2Si particles prevent grain boundary sliding effectively. Key words: magnesium alloys; microstructure; mechanical properties; ECAP; creep 0 引言 镁合金具有低密度、高比强度、高比刚度、高弹性模量、高阻尼性能，良好的尺寸稳定 性，优良的切削加工性及抗电磁干扰等特性，其应用领域已经从航空航天拓展到汽车和 3C 产品等行业[1]。ZK60 合金之所以受到人们青睐，是因为它是现在所有商用镁合金中强度较 高的一种，也是 Mg-Zn-Zr 合金系中性能最优越的一种。然而 ZK60 合金也存在塑性差、热 裂倾向严重及高温性能差等诸多不足之处，从而限制了其更广泛的应用[2]。 基金项目：国家自然科学基金（5