The X-ray characterization of the ultrafine-grained Cu processed by different methods of severe plastic deformation

The results of structural investigations of massive ultrafine-grained (UFG) Cu samples processed by severe plastic deformation (SPD) by torsion straining under high pressure, equal channel angular CECA) pressing and powder consolidation by torsion under high pressure were considered. X-ray patterns of the materials under study displayed common features consisting in significant broadening and changes in a profile of X-ray peaks and some increase in background integrated intensity X-rays scattering. It was concluded that dislocation distribution has some specific features. Assumptions were made about mechanisms of UFG structure formation and about the reasons causing an increase in mechanical properties of the investigated materials due to SPD. (C) 1997 Elsevier Science S.A.