(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 采用力学性能测试、光学显微镜、扫描电镜和能谱分析技术及切削性能测试对自行研制的含Bi易切削变形Zn-Cu合金铸态及挤压态的组织与性能进行研究。结果表明：Mn在Zn-Cu合金中易形成大而硬的块状相，对于提高锌合金的综合力学性能作用不明显，且可能产生不良影响；低熔点Bi相在Zn-Cu合金中铸态时以针状弥散分布，挤压态时以点状弥散分布，改善了Zn-Cu合金的切削性能；自行配制的Zn-1.2%Cu-0.5%Bi-X合金，切削性能良好，抗拉强度达到405 MPa，伸长率为19.0%，表现出较优的综合性能，可作为部分铜合金替代材料，用于制造轴承、连接件、五金和家电等结构件。
关键字: 变形锌合金；Bi；显微组织；切削性能
free-cutting deformation Zn-Cu-Bi alloy
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering,
Ministry of Education, Central South University, Changsha 410083, China）
Abstract:The microstructure and properties of self-developed Zn-Cu-Bi alloys in the cast and extruded conditions were investigated by mechanical tests, optical microscope, scanning electron microscope, energy spectrum analysis and machinability tests. The results show that Mn can easily form large and hard massive structure in the Zn-Cu alloy, which cannot improve the mechanical properties of Zn-Cu alloy obviously, and may bring worse effects. The machinability of the Zn-Cu alloy can be improved by needle dispersion distributed low-melting Bi phase in the cast condition and dot-like dispersion distributed Bi phase in the extruded condition. The self-developed Zn-1.2%Cu-0.5%Bi-X alloy is of good machinability, and the tensile strength and elongation of the alloy reach 405 MPa and 19.0%, respectively, showing good comprehensive properties. The alloy can be used to replace some copper alloys for making bearings, connectors, household appliances and other structural parts.
Key words: deformation zinc alloy; Bi; microstructure; machinability
