Examinations of Cu-Ag Composite Conductors in Sheet Forms

Abstract

Cold rolled Cu-24 wt% Ag composite was characterized and the effects of crystallographic structure and defect anisotropy and microstructure refinement on properties of the composite were studied. Characterization was carried out with high resolution scanning electron microscopy (SEM), x-ray diffractometer and mechanical testing. All the deformed samples exhibited {110}-texture that had impact on the anisotropic properties of the materials. The yield and tensile strengths were higher in the long transverse (LT) than in the rolling direction (RD). The resistivity was higher in the RD than in the LT. Increasing the rolling strain increased both the mechanical strength and electric resistivity. The property changes with strain were related to the Cu and Ag lamellae thickness. The thickness of the lamella was inversely proportional to the deformation strain. It was observed that the smaller the thickness of the lamellae, the higher the strength and the electric resistivity. A closer examination of the Cu and Ag components revealed that while the lamellae were well aligned in the LT direction, they were curved in the RD. The curved lamellae observed in the RD were attributed to the development of shear bands during rolling. Both the texture and shear bands were related to the anisotropy of the properties.