Improvement in the thermal conductivities and bending strengths of graphite film/Cu composites by matrix alloying with Zr

Graphite film/Cu composites were fabricated by the hot-pressing sintering method. The thermal conductivities and bending strengths of the composites were improved by matrix alloying with Zr. By sanding the surface of the graphite film, carbides were easily generated at the interface. The presence of carbides at the interface transformed the interfacial bonding characteristics from mechanical to physical-chemical bonding. Enhanced interfacial bonding could improve the thermal conductivity of the composites. The optimum Zr addition amount was 1.5 wt%, and the thermal conductivity of the composites was 725 W/mK. The enhanced interfacial bonding improved the composite bending strength. When the Zr concentration was 2 wt%, the composite bending strength was 34 MPa, which was an increase of 100 % compared with that of the absence of Zr.