Deformation processing and strength/conductivity properties of Cu-Fe-Ag microcomposites

Thermo-mechanical treatment was employed in this study to optimize the strength and conductivity of Cu-Fe-Ag microcomposites. The strength/conductivity properties of Cu-Fe-Ag microcomposites drawn to η = 4.8 without intermediate heat treatments (NH) were observed to be 1006 MPa/39% IACS and those drawn to η = 6.3 with three intermediate heat treatments (IH-3) were 939 MPa/56.2% IACS. A substantial increase of conductivity was obtained at the expense of a modest loss of the strength by the employment of intermediate heat treatments. The precipitation of impurities and alloying elements during intermediate heat treatment is thought to increase the conductivity due to the reduced impurity scattering. The activation volume was measured to be 170b3 for the as-drawn Cu-Fe-Ag (IH-2). Numerous particles were observed in Cu matrix and the spacing between these particles (∼30 nm) were found to be comparable to the activation length (170b = 43 nm). The most probable rate controlling mechanism of Cu-Fe-Ag microcomposites is suggested to be the interaction between dislocations and precipitates in Cu matrix.