Microstructure, Mechanical and Electrical Properties of Commercially Pure Copper Deformed Severely by Equal Channel Angular Pressing

In this study, commercially pure copper samples were severely deformed by equal channel angular pressing (ECAP) up to 8 passes in room temperature. The effect of sever plastic deformation on the microstructure, mechanical properties, electrical conductivity and electrical wear resistance of the cupper were investigated. In addition, the effect of induced strain on mechanical properties of the extruded cupper in each pass was studied. Field emission scanning electron microscope micrographs show the extreme evaluation of the microstructure after 4 to 8 ECAP passes, in which a large amount of nano and ultra-fine grains are observable. The mechanical properties of the pure cupper in each pass were estimated by compression testing and Brinell hardness method at room temperature. Yield strength and hardness increased by ∼390 MPa and 75HB respectively after 5-pass ECAP due to finer boundary spacing. Increasing the strength of pure copper led to only a minor decrease of the electrical conductivity. Hence, by applying ECAP, one can obtain the ultra-fine pure copper that can improve the mechanical properties without impairing the electrical conductivity. By reducing the applied strain in each pass (25%) of the ECAP process can be obtain the pure copper with higher strength. The electrical wear behavior of the samples was investigated by electrical discharge machining (EDM). The results indicate that, electrical wear of the extruded samples reduces compare to the original samples.