Study of Deformation-Processed Cu-10%Cr-3%Ag in Situ Composites

The structure,strength and electrical conductivity of Cu-10%Cr-3%Ag in-situ composites obtained by cold drawing combined with intermediate heat treatments have been investigated.The structures of the in-situ composites were examined by SEM.The results indicate that in as-cast condition,the morphology of Cr were dendritic;during deformation,Cr were drawn into fine ribbons and the Cr ribbons are curl and fold in cross-section.As the strain is increased,the ribbons became more fine and uniform.The tensile strength and electrical resistivity increase with increasing strain.Intermediate heat treatments have the effects on both the strength and the electrical resistivity.While the temperature of intermediate heat treatment is increased,the risistivity is decreasd first then increased with reverse trend as tensile strength.The optimum treatment temperature is 500℃ with the combinations of the electrical conductivity and the tensile strength given following: 82.8%IACS/791MPa(Φ1mm,B);80.6%IACS/809 MPa(Φ1mm,A);80.2%IACS/731MPa(Φ1.29mm,A) and 78.4%IACS/950MPa(Φ1mm,C).