Improved mechanical-physical performances of copper composites with reduced graphene oxide and carbonized polymer dots as multi-scale synergetic reinforcements

The development of high-performance (structure-function integration) Cu matrix composites have become a focus by introducing the novel hybrid carbon nanomaterials and giving full play to the synergistic effect. It is a great challenge to homogeneously disperse the ex-situ nano-filler within matrix for excellent performances. In this study, the two-dimensional reduced graphene oxide (RGO) and zero-dimensional carbonized polymer dots (CPD) were incorporated with Cu-based powders by the molecular level mixing (MLM) and high-energy ball milling (HBM) methods, respectively. Results revealed that RGO (MLM)/CPD (HBM)-Cu bulk composites sintered at 650 °C displayed higher ultimate tensile strength (367 MPa) and better failure strain (∼30%) as compared with pure Cu (MLM/HBM). Meanwhile, the electrical conductivity of RGO (MLM)/CPD (HBM)-Cu was almost equal to that of pure Cu (93.74% IACS), exhibiting a promising prospect in applications as advanced multifunctional structural materials. It was well proved that the interface strength of RGO-Cu and the dispersibility of hybrid reinforcements were improved by the incorporation of CPD, which further enhanced the synergistic effects of (CPD + RGO) and achieved better mechanical-physical performances.