Graphene interlayer for enhanced interface thermal conductance in metal matrix composites: An approach beyond surface metallization and matrix alloying

Abstract Poor wettability and acoustic mismatch between diamond and copper cause low interface thermal conductance and thus low thermal conductivity in their composites. In this work, beyond widely used strategies such as surface metallization and matrix alloying, in-situ grown graphene is introduced as a highly effective interlayer. The positive role of graphene on improving wetting between diamond and copper was supported by the increase of relative density, fractured surface morphology and interface microstructure. Thanks to the improved wetting and mitigated acoustic mismatch between diamond and copper, the interfacial thermal conductance is increased by ∼3.7 times in the diamond/graphene/copper composite as indicated by differential effective medium calculation. Such a positive role of graphene interlayer also agrees with the results from the time-domain thermoreflectance measurements. As a result, the thermal conductivity of the diamond/graphene/copper composite is 61% higher than that of the counterpart without graphene interlayer. This study provides a new approach for interface modification by 2D materials for a high TC of diamond/copper composite beyond surface metallization and matrix alloying.