Mechanical properties and thermal conductivity of graphene reinforced copper matrix composites

The dispersion of graphene in copper matrix significantly affects the mechanical and physical properties of graphene reinforced copper matrix composite (Gr/Cu). In our present study, graphene oxide (GO) with the negative charge was prepared by a modified Hummers' method and Cu powders were coated by hexadecyl trimethyl ammonium bromide (CTAB) to obtain the surface positive charge. GO-Cu powders were prepared by electrostatic self-assembly and Gr/Cu composites were fabricated by powder metallurgy. Morphologies of GO-Cu powders, microstructures and tensile fractographs of the Gr/Cu composites were observed. The effect of graphene contents on the mechanical properties and thermal conductivity of the composite were also investigated. The results show that GO with the negative charge is adsorbed on the surface of CTAB coated Cu powders with the positive charge, which realizes the homogeneous dispersion of graphene in the copper matrix composites. With increasing the graphene contents, the ultimate tensile strength and thermal conductivity of Gr/Cu composites initially increase and later decrease. However, the elongation to fracture of the composite gradually decreases.