Microstructures, mechanical and thermal properties of diamonds and graphene hybrid reinforced laminated Cu matrix composites by vacuum hot pressing

Graphene nanoplatelets (GNPs) and diamond are considered as reinforcements due to their high strength and thermal conductivity. The key problem is the interfacial bonding between the reinforcement and the matrix and the construction of the laminated structure in this study. The interfacial bonding between the reinforcement and the matrix is improved by coating copper on the surfaces of the reinforcement. Lamellar composites were successfully prepared by the combination of flake powder metallurgy and vacuum hot pressing. The results show that the mechanical and thermal properties of lamellar composites are better than the non-lamellar composites. With the increase of GNPs content, the laminated structure becomes more and more obvious, and the strength and thermal conductivity increase. When the content of GNPs reaches 1.5 wt%, the tensile strength, compressive strength and thermal conductivity of X–Y direction is 267 MPa, 663.33 MPa, 402 W/mK, respectively. In summary, copper-coated diamond and copper-coated GNPs improve the bonding with the matrix, and the lamellar structure extends the crack path and provides more heat conduction channels, thus increasing the mechanical and thermal properties of the composites. This work provides an effective method for the development of new thermal management structures and functional materials.