Microhardness and Microstructural Evolution of Pure Nickel Processed by High-Pressure Torsion

High-purity Ni was processed by high-pressure torsion (HPT) at room temperature under an imposed pressure of 6.0 GPa and a rotation rate 1 rpm through 1/4 to 10 turns, samples were then examined using Electron Back-Scattered Diffraction (EBSD) microhardness measurements. The results show that the grain size low-angle boundaries (LAGBs) gradually decrease with growth HPT revolutions while values increase. After turns processing, ultrafine-grained (UFG) pure reasonable value microstructure homogeneity can be achieved across disk, thereby giving great potential for applications in micro-forming. A refinement model severe plastic deformation (SPD) is proposed.