Enhancing mechanism of interfacial metal element on the thermal transport across Cu-graphene interfaces revealed by molecular dynamics simulations

Enhancing the interfacial thermal conductance (ITC) between graphene fillers and a metal matrix is critical for the practical application of metal matrix composites as thermal management materials. In this work, the interfacial metal element (M) is utilized to enhance the ITC in copper matrix composite filled with trilayer graphene (TLG) through non-equilibrium molecular dynamics (NEMD) simulations. The results show that different impacts are induced in enhancing the ITC of Cu-TLG interfaces. Specifically, a positive enhancing effect is introduced by interfacial elements (Ti and Co) chemically bonded with copper matrix and TLG. The positive enhancing mechanism of a metal interfacial element on the ITC is further illustrated in terms of the phonon density of states (PDOS) in the Cu-M-TLG interface region. It should be stressed that the ITC increases gradually with the increasing interfacial Ti layer thickness (from 1 to 5 layers). In contrast, a negative enhancing effect is introduced by interfacial elements (Au and Pd) physically and mixed bonded with copper and TLG because of Cu-M (M = Au/Pd) interface caused a strong phonon scattering. The enhancing mechanism on the ITC of Cu-TLG composite induced by the interfacial metal element is expected to provide a theoretical guideline for improving the overall thermal conductivity of metal matrix composite materials.