Diamond/aluminum composites processed by vacuum hot pressing: Microstructure characteristics and thermal properties

As promising thermal management materials, diamond/Al composites with 20–50 vol.% diamond were fabricated by a simple powder metallurgy method called vacuum hot pressing (VHP). The microstructure characteristics and thermal properties of the composites were studied. The results reveal that no aluminum carbide is formed at the interface and the VHP composite with 50 vol.% diamond exhibits a thermal conductivity of 496 W/mK, over 85% of the theoretical prediction by the differential effective medium (DEM) scheme, due to good interfacial bonding and high interface conductance. As a comparison, the composites consolidated by spark plasma sintering (SPS) exhibits lower thermal conductivity due to poor interfacial bonding. Thus, VHP is proved to be a more favorable way than SPS to fabricate diamond/Al composites with high thermal properties for heat management applications.

► A novel vacuum hot pressing process developed to consolidate diamond/Al composites.
► Compare the microstructure characteristics and thermal properties of the composites prepared by SPS and by VHP.
► Discuss the possible mechanisms of the variations of interfacial bonding and interface conductance formed by SPS and VHP.
► Enhanced thermal conductivity via improving interface conductance of the composites.