Mechanical and electrical properties of Cu-Ag nanocomposites processed by equal channel angular pressing (ECAP)

Abstract

Equal channel angular pressing was carried out on Cu-Ag composites at room temperature. ECAPed Cu-Ag exhibited ultrafine structure with the shape and distribution of Ag phase dependent on the processing routes. In route A, the initial lamellae of Ag phase were elongated along the shear direction and developed into filaments whereas the initial lamellae became finer by fragmentation with no pronounced change of the shape in route Bc. The hardness of ECAPed Cu-Ag is greater than that of ECAPed Cu. The higher hardness in Cu-Ag is ascribed to the more effective matrix strengthening due to the dislocation storage at the interface and the precipitation hardening. The hardness of ECAPed Cu-Ag was lower than the drawn Cu-Ag at the same deformation strain because of the less effective refinement and elongation of the two-phase filamentary microstructure. The application of ECAP in Cu-Ag was found to be effective in the modification of structure, shape and distribution of phases in composite and the increase of the strength.