Effect of deformation techniques on the microstructure and mechanical properties of a copper alloy

Abstract

The microstructure and mechanical properties of a Cu-0.25%Mg alloy subjected to either equal channel angular pressing (ECAP) or combined cold working, including ECAP followed by rolling and then drawing at room temperature, were investigated. ECAP led to the formation of strain-induced boundaries and the development of ultrafine equiaxed grains with an average size of about 0.6 μm after 4 passes. The microstructure after the combined cold working included fibrous grains elongated in the rolling/drawing direction with a sharp texture containing <001> and <111> fibers. The transversal grain size after combined cold working to a total strain of 5.7 achieved 0.43 μm. The yield strength and ultimate tensile strength after ECAP to a total strain of 9.6 were 570 and 600 MPa; whereas those after combined cold working to a total strain of 8.7 were 745 and 780 MPa, respectively. The reason of the difference in mechanical properties was discussed.