Properties of nanocrystalline CuAg foil prepared via electrodeposition

In this study, we fabricated nanocrystalline CuAg foils with a thickness of 40 µm using an electrodeposition method, and evaluated its structure and properties. Using an appropriate combination of organic additives and a continuous Ag+ supply system, compact and bright nanocrystalline CuAg foils were obtained. The as-deposited CuAg foil consisted of supersaturated CuAg crystals with a mean diameter of ~13 nm, and exhibited high ultimate tensile strength (993 MPa), high electrical conductivity (66.7% IACS), and moderate ductility. With mild annealing at 100 °C, both the strength and the conductivity were improved further (1043 MPa and 68% IACS, respectively), achieving properties comparable to those of the state-of-the-art deformed CuAg of greater thicknesses. Upon annealing at ~200 °C, Ag atoms that segregated at the grain boundary began to precipitate and grow, thereby destabilizing the Cu nanograins. This resulted in grain growth, decreased strength, and increased conductivity.