Fabrication of high-strength graphene nanosheets/Cu composites by accumulative roll bonding

Graphene nanosheets (GNSs) reinforced copper matrix composites have been considered as the potential copper materials with high strength and high conductivity. Here, the high-strength GNSs/Cu composites were fabricated by accumulative roll bonding (ARB). The ARBed GNSs/Cu composites manifested a good interfacial bonding and a significant grain refinement. The average spacing of high-angle boundaries along the normal direction was less than 150 nm after 6 ARB cycles, which was finer than that of the ARBed Cu. In addition, there existed a nano-layer with grain sizes of 50-70 nm and the high-density deformation-twins at the interface. The tensile strength of the ARBed materials enhanced with the number of cycles. After six cycles, the tensile strength of GNSs/Cu composites reached 496 MPa. This strength was 275 and 33 MPa higher than those of the annealed copper and the ARBed copper, respectively due to the strain hardening and grain refinement. Furthermore, the addition of GNSs into Cu matrix accelerated the grain refinement and the strength improvement.