Production of nanostructure copper by planar twist channel angular extrusion process

This study challenges experimentally, the feasibility of new severe plastic deformation method entitling planar twist channel angular extrusion (PTCAE) for fabrication of nanostructure pure copper. The results indicated, deformed copper has 71%, 69% and 113% higher yield strength, ultimate tensile strength and hardness magnitude as compared to the as-received condition. Additionally, the fractography of tensile sample showed the mechanism alteration from multiple dimples to cleavage planes, associating the production of brittle type material. Moreover, the reduction of bulk formability index of the processed copper in comparison with the initial condition confirms the decrease of material ductility due to the strain hardening and grain refinement phenomena. The grain size of about 270 nm is also attained after the single pass processing. Eventually, a grain size correction coefficient is proposed to the strength to hardness ratio as a rule of thumb for estimation of strength by means of hardness irrespective of the grain size of the pure copper material.