Effect of Cold Work on the Thermal Conductivity of Copper

Abstract

Measurements were made of the thermal conductivity of each of five samples of copper rod which had been strained to different degrees by cold drawing. The measured thermal conductivity of the most highly strained sample (drawn to 50 per cent reduction of area) was about 11 per cent lower than that of annealed material. The flow of heat through a stationary metal-to-metal joint is inhibited by the reduced conductivities of the plastically deformed surface asperities forming the real contact points within the joint. The complex straining processes involved in the mating of asperities make it difficult to predict quantitatively the overall effect on a joint's conductance, but the reduced thermal conductivities may be partially responsible for the very low joint conductances previously attributed to changes in metal ‘hardness’.