Effects of diamond/Al interface structure evolution on interfacial thermal conductance during the carbonization of the Cr interlayer

Abstract

The correlation between the interface structure evolution and the interfacial thermal conductance (ITC) in diamond particles reinforced Al matrix (diamond/Al) composites has been largely unclear. Herein, diamond/Cr/Al nanolayered structures with the interlayers in different carbonization stages were prepared via magnetron sputtering and annealing treatment to simulate the interfaces in diamond/Al composites. As the annealing time increases, the formed Cr3C2 phase progressively grows from discrete particles to a continuous layer at the diamond/Cr interface, during which the thickness of the carbide layer gradually increases. The formation of Cr3C2 phase improves the interface bonding and provides a more convenient channel for the heat exchange of hot carriers between the interfaces. Accordingly, the ITCs of the samples gradually increases with the annealing time and reaches the maximum value of 436.66 MW/(m2·K) at 120 min due to the formation of a thin and continues Cr3C2 layer. However, considering high interfacial thermal resistance was introduced at the interface when the Cr3C2 interlayer is too thick, the ITC of the sample decreased to 321 MW/(m2·K) as the annealing time extended to 240 min. In addition, Al8Cr5 phase is generated at the Al/Cr interface, but its impact on the ITC of the samples is negligible due to the small amount.