热处理对Zn-1.1Cu-0.5Bi合金组织与性能的影响

Effects of heat treatment on microstructure and properties of Zn-1.1Cu-0.5Bi alloy

采用力学性能测试、光学显微镜、扫描电镜、X射线衍射分析、切削性能测试等技术手段,研究了热处理对易切削变形Zn-1.1Cu-0.5Bi合金组织与性能的影响。结果表明:使Zn-1.1Cu-0.5Bi合金强度、硬度提高的较佳热处理工艺为350℃,保温30 min。350℃×30 min热处理态合金组织变得更均匀,但伴随有晶粒的明显长大;热处理态合金比挤压态屈服强度稍有下降,抗拉强度提高11.7%,伸长率有所下降。Zn-1.1Cu-0.5Bi合金铸态切削性能最好,挤压态和热处理态切削性能稍有下降,热处理对合金切削性能改善不明显。

Effects of heat treatment on microstructure and properties of a free-cutting deformation Zn-1.1Cu-0.5Bi alloy were investigated by means of mechanical tests,optical microscopy,scanning electron microscopy,X-ray diffraction and machinability tests.The results show that the heat treatment process of heating at 350 ℃ for 30 min is recommended to improve the strength and hardness of Zn-1.1Cu-0.5Bi alloy based on experiments.The alloy has more homogeneous microstructure after heat treatment at 350 ℃ for 30 min than that in extruded condition,but accompanying with significant grain growth.Compare with the extruded condition,yield strength of the alloy decreases slightly after heat treatment,the tensile strength increases by 11.7%,and the elongation is slight decrease.The machinability of Zn-1.1Cu-0.5Bi alloy is best in the cast condition,and it becomes slightly worse in the extruded and heat-treated conditions.Heat treatment can not improve the machinability of Zn-1.1Cu-0.5Bi alloy obviously.