Modification of microstructure and strength/conductivity properties of Cu-15 Ag in-situ composites by equal-channel angular pressing

Abstract

Equal-channel angular pressing (ECAP) was carried out on Cu-15 wt% Ag in-situ composites at room temperature. The ECAPed Cu-15 Ag in-situ composite exhibited an ultra-fine two-phase structure with the shape and distribution of the Ag phase dependent on the processing routes. In route A, the initial lamellae of the 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 strength/conductivity combination of 743 MPa/78.6 %IACS was attained in Cu-15 Ag processed by route Bc. The strength of Cu-15 Ag ECAPed using route Bc was greater than that ECAPed using route A, suggesting that substructural strengthening combined with precipitation strengthening is superior to interface strengthening. The electrical conductivity decreased more drastically in route Bc than in route C due to the frequent fragmentation of the lamellae in route Bc.