Enhancement of strength and electrical conductivity for hypo-eutectic Cu-12Ag alloy

A thermo-mechanical treatment was designed for a hypo-eutectic Cu-12Ag alloy in order to enhance its tensile strength, as high as 1189 MPa, at the relatively minimal cost of the electrical conductivity, as good as 71.9%IACS, the combination of strength and conductivity being far superior to other Cu-Ag alloys ever reported in the literature. To understand detailed mechanisms, a Cu-7Ag alloy and a Cu-12Ag alloy, which is beyond the maximum solubility (8 wt%) of Ag in Cu, were chosen for comparison and homogenized at 777 °C for an hour followed by aging at 400 ℃. The peak-aged alloys were then cold-rolled with a 99% reduction. Cu-7Ag showed higher hardness than that of Cu-12Ag at peak aging. However, Cu-12Ag showed higher strength and conductivity than those of Cu-7Ag after cold rolling. The elongated dispersed Ag phases in Cu-12Ag attributed extra strengthening, while keeping a minimal reduction of the conductivity after cold rolling.