Design of bicontinuous metallic nanocomposites for high-strength and plasticity

We demonstrate design of Cu/Mo nanocomposite thin films with bicontinuous intertwined morphologies for high strength and plastic deformability. Through co-sputtering Cu and Mo at different temperatures, nanocomposites with lateral and random concentration modulations (LCMs and RCMs) were fabricated. Ligament size and coherency of the Cu/Mo interfaces was also controlled via the deposition conditions. It was discovered that nanocomposites with LCM structure and coherent interfaces have high strength but limited deformability. Enhanced deformability was achieved when the interface was altered to semi-coherent, although plasticity was localized in kink bands. The RCM structure design with semi-coherent interfaces showed an excellent combination of high flow strength and plastic deformability due to suppression of shear and kink bands.