Strength and electrical conductivity of Cu–9Fe–1.2Co filamentary microcomposite wires

The strength and conductivity of drawn Cu–9Fe–1.2Co microcomposite wires combined with intermediate heat treatments have been investigated. During cold working the primary and secondary dendrite arms are aligned along the drawing direction and elongated into filaments. The strengthening in Cu–Fe–Co microcomposites results from the presence of the aligned Fe–Co filaments and correlates with the fineness of the microstructural scale. The predicted strength using the Hall–Petch equation is 789 MPa, which is in reasonably good agreement with the observed strength (855 MPa). The increase of conductivity in Cu–Fe–Co after intermediate heat treatments at 450°C is attributed to the precipitation of Fe and Co atoms which were dissolved during heavy deformation processing. The tensile strength/electrical combination of 855 MPa/53.3% IACS was achieved in Cu–9Fe–1.2Co microcomposite at the cold drawing strain ETA=6.2.