An examination of microtexture and microstructure in ultrafine-grained nickel

A detailed orientation imaging microscopy (OIM) investigation was conducted to evaluate the microstructural characteristics in samples of pure nickel processed using three different procedures of severe plastic deformation (SPD): equal-channel angular pressing (ECAP), high-pressure torsion (HPT) and a combination of ECAP and HPT Electron backscattering diffraction (EBSD) techniques were employed to measure the microtextures and the distributions of the misorientation angles. A thorough analysis of the microtexture revealed the shear plane normal and shear direction for UFG nickel obtained by various kinds of severe plastic deformation. It is shown that a combination of ECAP and HPT leads both to a greater refinement in the microstructure and to a smaller fraction of boundaries having low angles of misorientation.