Multilayer graphene interface enabled ultrahigh extensibility for high performance bulk nanostructured copper

Nanostructured metals are strong, but have poor ductility and thermal stability, and require extreme preparation conditions. We conceive a strategy of ultrahigh extensibility enabled by van der Waals interface for fabricating bulk nanostructured metals via plastic deformation under moderate conditions. As an example, laminated copper grains are continuously refined to be less than 50 nm in thickness, owing to interlayer sliding of multilayer graphene and co-deformation of Cu–C along their interfaces in a conventional cold-rolling process. The as-rolled nanostructured copper with 34,000 % deformation degree has superior combination of ultimate tensile strength and electrical conductivity up to (827 MPa, 85.2%IACS), and exhibits extraordinarily thermally stable keeping an average grain size as small as ∼600 nm even after annealing at a temperature near the melting point. This van der Waals interface strategy provides an efficient and industrially scalable route for fabricating high performance bulk nanostructured metals via conventional methods under moderate conditions.