Achieving High Strengthening Efficiency and Good Balance between Strength and Ductility/Electrical Conductivity in the Laminated RGO/Copper Composites

Copper matrix composites reinforced with hard reinforcements typically exhibited increased strength, often at the expense of ductility and electrical conductivity. In this work, reduced graphene oxide (RGO)/Cu composites with a laminated structure were developed to balance these properties. Microstructural analysis highlights the intercalation of RGO layers creating a distinctive laminated structure. At the RGO–Cu interfaces, traces of CuO and Cu2O serve as chemical anchors, enhancing interface strength. With a minimal graphene content of only 0.024 vol %, the composite achieves a yield strength of 240 MPa and a strengthening efficiency of 572, while preserving elongation and electrical conductivity at comparable levels to the pure Cu sample (36.4% and 97.1% IACS, respectively). The composites are reinforced through several mechanisms: load transfer, the Orowan mechanism, and grain refinement, which collectively enhance the strength. Additionally, they are toughened by the formation of interlaminar copper (Cu) pillars, which effectively resist tearing. Furthermore, the unidirectional alignment of the RGO within these structures facilitates efficient electron transport, contributing to good electrical performance. The results presented demonstrate that this research successfully balances several mutually exclusive properties in metal matrix composites such as strength, ductility, and electrical conductivity. This achievement provides a promising direction for the development of advanced metal matrix composites.