Study of Mechanisms to Produce Ultra Fine Nano Grained Copper through Thermal Cycling Process

Abstract

Reducing the average grain size of polycrystalline metals and alloys is a traditional way of increasing their strength. While high strength and good ductility rarely exist simultaneously in any material, ultrafine grains exhibit the optimal combination between both. One of the principles to develop high conductivity and high strength is the thermal cycling process. Pure copper and copper alloys are widely used because of their high electrical conductivity, high heat transfer, corrosion resistance and excellent formability. One of the main challenges before the manufacturers is to produce high conductivity copper with the right combination of mechanical properties for specific applications. The strength of pure copper is low and any strength gained through cold working comes at the expense of decrease in electrical conductivity. The present work aims to propose a methodology for developing copper, which possesses good strength and also high electrical conductivity simultaneously. Most researches have concentrated on Cu–Al, Cu–Zn, Cu–Au, Cu–Ag, Cu–Cr alloys and so on, while the studies on pure copper have been very limited. In the present work, the influence of thermal cyclic treatment on the kinetics of recrystallization has been determined. Solution annealed copper has been subjected to heavy cold deformation followed by subsequent thermal cycling to produce ultra fine grained structure. The effect of this treatment on microstructural changes and property enhancement of pure Copper has been investigated. The work closely describes the recrystallization and grain growth kinetics under the cyclic process. The ultra fine grained copper with submicrometer grains can achieve superior mechanical properties and electrical conductivity