Heat conduction and thermal expansion of copper–graphite composite as a heat sink

This study presents the evaluation of the heat transfer characteristics and mechanical deformation of new composite material heat sinks using experimental and computational approaches. First, we synthesized a composite material composed of copper (Cu) and graphite (C) with 60 wt% Cu, with higher thermal conductivity and a lower thermal expansion coefficient than pure Cu and aluminum. The composite material was used to fabricate a heat sink integrated with an insulated-gate bipolar mode transistor (IGBT) module for enhanced heat dissipation from the IGBT. Compared with the pure Cu heat sink, the composite heat sink decreases the average temperature of the IGBT module by approximately 22 K. It also decreases the total deformation of the heat sink caused by thermal expansion of the material by 78% and the equivalent stress by 25.2%. This study introduces a way to use Cu-C composite materials in many potential applications, such as heat sinks integrated with IGBT inverters.