Mechanical and Physical Property Changes of Cu-Ni-Si-Sn-Fe-P Copper Alloy System According to the Heat Treatment Conditions

The influence of aging treatment, addition elements and rolling reduction ratio on the microstructure, mechanical, electrical and bendability properties of Cu-Ni-Si-P-x (x = Fe, Sn, Zn) alloys for connector material application was investigated. SEM/EDS analysis exhibited that Ni2-Si precipitates with a size of 20~100 nm were distributed in grains. Fe, Sn, Zn elemnets in Cu-Ni-Si-P alloy imporved the mechanical strength but it was not favor in increasing of electrical conductivity. As higher final rolling reduction ratio, the strength and electrical con- ductivity is increased after aging treatment, but it indicated excellent bendability. Especially, Cu-2Ni-0.4Si-0.5Sn- 0.1Fe-0.03P alloy show the tensile strength value of 700MPa and the electrical conductivity was observed to reach a maximum of 40%IACS. It is optimal for lead frame and connector. (Received July 15, 2012; Revised August 20, 2013; Accepted August 29, 2013)