Molecular dynamics study on the impact of defects on phonon thermal conductivity in copper–graphene composites

This study investigates the effects of copper–graphene interfaces and grain boundaries on phonon-thermal conductivity in copper–graphene composites. The investigation was carried out using atomistic modelling through molecular dynamics (MD) simulations. Graphene’s exceptional thermal conductivity makes it a promising candidate for enhancing heat transfer in electronic devices. However, when integrated into copper matrices, the presence of defects like high-angle grain boundaries and interfacial regions can significantly alter heat dissipation. The results show that introducing a graphene layer into the copper matrix reduces the composite’s thermal conductivity by 40%, from [Formula: see text] [Formula: see text]W/m*K to [Formula: see text] [Formula: see text]W/m*K. The introduction of high-angle grain boundaries in copper further decreases the thermal conductivity to [Formula: see text] [Formula: see text]W/m*K as far as grain boundaries in the copper matrix lead to significant phonon scattering. Moreover, the presence of defects in both graphene and copper reduces thermal conductivity to [Formula: see text] [Formula: see text]W/m*K. The combined effect of copper–graphene interfaces and grain boundaries in both materials leads to the most substantial reduction in thermal conductivity, reaching [Formula: see text] [Formula: see text]W/m*K. These findings demonstrate the critical role of interface and grain boundary defects in modulating the thermal performance of copper–graphene composites and provide insights for optimising the thermal design of advanced materials for thermal management applications.