Grain boundary distributions, texture and mechanical properties of ultrafine-grained copper produced by severe plastic deformation

Microstructure, texture and grain boundary distributions in the ultrafine-grained (UFG) copper obtained by severe plastic deformation were studied in the as-received state and after cold rolling. Grain refinement to 0.21 mu m accompanied by the change of the grain boundary (GB) distribution towards a random one occurred during severe deformation using an equi-channel angular (EGA) scheme of pressing. More than 90% of grain boundaries were found to be high-angle boundaries. Strong rolling texture formation, an increase of the fraction of low-angle boundaries and grain growth were revealed after cold rolling of the UFG sample. These microstructural transformations oro are compared with those generated by rolling in conventional coarse grained copper. The high strength and ductility of UFG materials produced by severe plastic deformation are discussed in terms of the observed microstructural features.