▎ 摘　　要

The application and performance of graphene-reinforced composites can be benefited from the easy fabrication of graphene and good dispersion of them in the matrix. Here we reported the fabrication of in-situ graphene/ copper (Gr/Cu) nanocomposites by an accumulative roll-compositing (ARC) process featured by ultrahigh rolling cycles/strains. By sandwiching in copper sheets, commercial graphite foils can be effectively delaminated into few-layer graphene sheets by ARC, without the need of any additives or chemical treatments. The ARC-induced delamination of graphite was mediated by the shear-induced slip and debonding of graphitic planes, for which the critical stress/strain conditions were analyzed. The plastic-deformation-based method simultaneously enabled the uniform incorporation of the delaminated graphene sheets into Cu matrix. The as-produced bulk Gr/ Cu nanocomposites exhibit an excellent combination of strength, ductility and electrical conductivity, with the maximum tensile strength of -686 MPa and electrical conductivity above 70% IACS. Our study showed the high effectiveness of ARC processing for exfoliating graphite into graphene nanosheets, and the great potential for enhancing the contributions of graphene by improving their dispersion and bonding with the matrix.