Enhanced tensile ductility and toughness in nanostructured Cu

Pure copper with ultrafine grain sizes and nanoscale subgrain (dislocation) structures was prepared by using severe plastic deformation through cold rolling at subambient temperatures, with or without subsequent recovery annealing. We report coexisting high strength and tensile ductility (large elongation to failure and ductile fracture). Factors leading to the simultaneous strengthening and toughening with increasing cold deformation and microstructural refinement are discussed.