Interfacial strengthening and self-healing effect in graphene-copper nanolayered composites under shear deformation

The mechanism of interfacial strengthening and self-healing effect in graphene-copper nanolayered (GCuNL) composites under shear deformation is investigated at a theory and quantitative level. It is found that the interfacial constraining effect between graphene and copper layer highly improves the shear strength and toughness of GCuNL composites. The interlayer distance between graphene monolayers and the crystal stacking orientation of copper layers plays an important role in the shear yield strength of composites. The shear toughness of composites is jointly determined by the crystal orientation of copper layer and the chirality of graphene. The shear failure strain of zigzag-based composites is remarkably higher than that of armchair-based composites, while the shear failure stress of (100)-stacking composites is larger than that of (111)-stacking composites due to rotation of slip bands. Furthermore, we find a remarkable self-healing effect in GCuNL composites by interfacial trapping dislocations. The self-healing ability is determined by the interlayer distance between graphene monolayer. Synthesizing both the strengthening and self-healing effect, the optimum distance between graphene monolayers is ranging from 5 to 15 nm.