Graphene defect engineering for optimizing the interface and mechanical properties of graphene/copper composites

A graphene defect engineering strategy was proposed in this work to tailor the interface and mechanical properties of graphene/Cu composites. Plasma treatment was used to create surface defects (5-10 nm nanopores) on the basal-plane of starting graphene material but without considerably damaging the graphene structure. It was demonstrated that the CuxOy oxides were in situ formed at the defect sites of plasma-treated graphene in the sintering process, which played a bridging role in enhancing the interfacial adhesion of graphene with Cu matrix. Compared to the composites with untreated graphene, the composites with plasma-treated graphene exhibited a higher strength enhancement, and better interface stability in response to thermal cycling, which was ascribed to the CuxOy coordinated improved interfacial bonding that provided efficient load transfer and thermal stress relaxation. Nevertheless, the overlong plasma treatment could severely damage the graphene structure and result in a reduced strength enhancement. This study suggests that the rational defect engineering of graphene is an efficient approach for optimizing the interface and mechanical properties of graphene/metal composites. (C) 2018 Elsevier Ltd. All rights reserved.