Numerical and experimental studies of pure copper processed by a new severe plastic deformation method

A new technique named elliptical cross-section spiral equal-channel extrusion (ECSEE) was proposed for producing ultrafine-grained materials by severe plastic deformation. In this modification, an elliptical cross-section torsion channel is designed in the ECSEE die, to impose extra shear strains to the sample. To study deformation behavior in the ECSEE process, finite element analysis (FEA) was carried out by using DEFORM-3D software. The situational pressing load showed the additional torsion shear increased the loading force. The effective strain distribution decreased from the periphery to the center of the sample cross-section. To further investigate the deformation and refinement of ECSEE process, experimental studies were performed on commercially high pure copper (99.7%). The Vickers hardness test results showed the sample was greatly improved compared with the as-annealed one due to the severe deformation of ECSEE process. In the metallographic observations, the grains were refined well in the severe deformation area, especially in the shear stress suffered area.