Folded graphene reinforced metal matrix nanocomposites with comprehensively enhanced tensile mechanical properties

Abstract

It is urgent to develop advanced materials with high strength, high toughness and good ductility for modern engineering structures. Graphene reinforced metal matrix nanocomposites exhibit significantly enhanced strength and toughness, but their ductility remains relatively low due to the inherent tensile brittleness of graphene. Inspired by the origami concept, we utilize the surface hydrogenation method to develop an armchair-like folded graphene (AFG) structure as reinforcement for metal matrix composites. Molecular dynamics simulations show that the AFG structure can simultaneously enhance the tensile strength, stiffness, ductility, and toughness of copper (Cu) matrix composites. Compared with pristine graphene/Cu nanocomposites, AFG/Cu nanocomposites exhibit better ductility and toughness, while maintaining comparable strength and stiffness. Furthermore, the mechanical properties of AFG/Cu nanocomposites can be tuned by altering the degree of AFG folding and the distances between adjacent hydrogenated zones. The strengthening and toughening mechanism is that mechanically strong AFG can effectively block dislocation propagation across the metal-graphene interface before it unfolds to fracture. Such mechanism can be extended to other 2D nanomaterials reinforced metal matrix nanocomposites, opening up an avenue for developing high-performance nanocomposites.