Copper Tin Nickel Phosphorus Alloys With Improved Strength and Formability and Method of Making Same

A new copper-based alloy is described along with a processing method to make a strip that can be used for various automotive interconnects. The alloy process combination yields a material with high strength and electrical conductivity with excellent formability. The combination of properties result from a Cu-Sn-Ni-P alloy with optional Mg additions and thermal-mechanical processing to make an alloy with a conductivity of 40% IACS, yield strength of 80 KSI, bend formability of 1t/1t minimum, and stress relaxation of 65% at 150° C. after 1000 hours. Processing can be modified to increase formability at the expense of yield strength. Improvements to conductivity come from changes in chemistry as well as processing. The new chemistry-process optimization results in a low cost alloy of Cu-Sn-Ni-P-Mg.