Thermal conductivity of metal-graphene composites

In this paper the results of numerical simulations and experimental studies are presented which describe potential and limitation of applications of single-layer (SLG) and multi-layer (MLG) graphene for thermal conductivity enhancement (TCE) of copper. A series of composite structures were studied which are representative of most widely used systems. The influence of structural parameters on the macroscopic thermal conductivity was analyzed, both experimentally and by numerical simulations. Analytical and Finite Element Method modeling were carried out to investigate a wide range of phenomena, including the effect of copper-MLG interface, copper grain size, volume fraction, thickness and orientation of MLG platelets as well as spatial distribution of MLG defined by percolation factor. Both modeling and the experimental results show that the volume fraction of MLG regions, their size, orientation and spatial distribution may significantly affect the thermal conductivity of metal matrix composites. TCE can be obtained for the laminate-like structure or particulate composites with highly aligned MLG regions. The thermal conductivity of such composites is strongly anisotropic and enhanced in the direction perpendicular to the layers. The results obtained in this study predict that SLG will have a negative effect on the thermal conductivity of copper matrix composites. (C) 2016 Elsevier Ltd. All rights reserved.