Investigation of microstructure and mechanical properties of Cu-Ni alloy processed by equal channel angular pressing

The Copper-Nickel alloy, C70600, was subjected to severe plastic deformation by the equal channel angular pressing (ECAP) technique. The material was pressed at room temperature along route BC for eight passes. Microstructural analysis and mechanical characterization of the material were done for each of the ECAP pass samples. The initial homogenized material having equiaxial grains of average grain size 75 mu m was reduced to 20 mu m after eight ECAP passes. Electron backscatter diffraction data presented an increase in low angle grain boundaries with an increase in the number of ECAP passes. Initially, the ultimate tensile strength and the hardness increased by 56% and 94% respectively. After the fifth ECAP pass, a drastic reduction in ultimate tensile strength and ductility was witnessed. Hardness value remained constant after the fifth ECAP pass. Fractography analysis indicate the ductile mode of fracture with reduced dimple size at higher ECAP passes.