Microstructural Characterization of Cold-Drawn Cu-Ni-Si Alloy Having High Strength and High Conductivity

A Cu alloy with high strength and high conductivity, characteristics that are generally traded off, was developed applying discontinuous precipitates as a hardening agent. We observed nanotwins by electron microscopy, which are rarely observed in cold-drawn Cu-Ni-Si alloy. Because nanotwins have little effect on electrical resistivity while effectively interfering with dislocation movement, they are one of the key factors that allow the trade-off characteristics of high strength and high conductivity to manifest simultaneously. Furthermore, we found the development of considerable internal strain and geometrically necessary dislocation due to discontinuous precipitation during aging without deformation.