Strength and electrical resistivity of heavily worked copper

Abstract

Copper and its alloys are a topic of interest for various cryogenic conductor applications. Often, it is used as a supporting matrix for superconducting filaments requiring that it have good strength and high conductivity. One of the best methods to increase strength while preserving conductivity is work hardening. In this study, CDA101, CDA110, and C182 copper were processed by a severe plastic deformation (SPD) procedure called equal channel angular extrusion (ECAE). In this study we explore the relationships between the levels of plastic strain and annealing with tensile and hardness properties, grain size, and electrical resistivity. While C182 has the highest strength, it also has the lowest conductivity. CDA101 and CDA110 both retain over 95% of their conductivity in the fully worked state, while C182 has about 40% of the IACS value. Saturation of strength occurs around 3-4 ECAE passes. It is concluded that a lower amount of plastic strain via ECAE is best for creating a material with the highest combination of strength and conductivity, and is suitable for high strength high conductivity applications.