Short-Range Order Enhances Strength and Tensile Ductility in Nanocrystalline Silver with Intercalation of Amorphous Nickel Nanolayers

Abstract Silver, known for its high thermal and electrical conductivity, is an ideal metal for thin-film electrode applications. Because alloying can negatively affect conductivity, enhancing the strength and resistance to strain poses a tremendous challenge when applied to pure Ag films. Herein, in both experiments and atomistic simulations, we discover a nanoscale strengthening mechanism by intercalating ultrathin amorphous Ni-rich layers between pure nanocrystalline Ag films, resulting in the formation of a multilayered Ag and Ni-Ag alloy material with a stable grain size (22 nm) combining the highest hardness (2.6 GPa), tensile strength (677 MPa) and plastic elongation (6.6%) ever reported for this metal. The integration of amorphous Ni-Ag alloy nanolayers substantially improves the strain hardening behavior and extends the tensile ductility compared to standard crystalline Ag/Ni nanolaminates at an equivalent Ag layer thickness. This phenomenon results from strain-induced chemical short-range order within the amorphous Ni-Ag nanolayers during plastic deformation. The new nanoscale strengthening mechanism can be easily leveraged to develop nanocrystalline films with exceptional mechanical and physical properties.