Graphene core–shell structure guided functionalized interface to prepare high-strength, high-plasticity, and high-conductivity copper matrix composites

Abstract

Integration of excellent mechanical and electrical properties is the vital requirement for engineering application of copper matrix composites (CMCs). In this study, reduced graphene oxide-coated submicron spherical Cu (SSCu@rGO) core–shell structure as a composite reinforcement phase was used to reinforce CMCs (SSCu@rGO/Cu composites). A perfect balance among high strength, high plasticity, and high electrical conductivity (EC) was achieved. Notably, SSCu@rGO promoted the uniform distribution of rGO, and led to the reaction between the interface of rGO and Cu reacted to form an optimized interface structure containing Cu2O and Cu4O3 nanotransition layers with load transfer and coordinated deformation functions. A comparative study was conducted between 0.1 wt% rGO-coated SSCu reinforced CMCs (SSCu@0.1 wt%rGO/Cu composites) and 0.5 wt% rGO-coated SSCu reinforced CMCs (SSCu@0.5 wt%rGO/Cu composites). When the mass fraction of SSCu@0.1 wt%rGO was 30 wt%, the tensile strength (TS) and elongation (EL) were found to be 309 MPa and 55%, respectively, and the strength plastic product (UT) was as high as 16995 MPa%, which is 2 times that of pure Cu. The yield strength (YS) was 171 MPa, which is about 3 times that of pure Cu. The EC remains the same as that of pure Cu, both correspond to 93% IACS (International Annealed Copper Standard). Further, its strengthening mechanism including strength mechanism, plasticity mechanism, and EC mechanism was comprehensively and elaborately discussed. This study shows that the use of graphene and submicron metal to prepare composite reinforcement phases can lead to the achievement of excellent matching of high UT and high EC of CMCs.