Finite element simulation and experimental investigation on thermal conductivity of diamond/aluminium composites with imperfect interface

A diamond/aluminium composite with tungsten carbide coating on diamond particles was fabricated by the infiltration method, with the thermal conductivity increasing up to 588 W/m K. To profoundly understand the thermal conduction behaviour of the composites, a three-dimensional computational model was constructed by using the finite element method with imperfect interfacial thermal conductance. Based on the differences among fracture feature of the composites, the effects of inhomogeneous and homogeneous interfacial thermal conductance (h) on thermal conductivity of composites were studied. The results show that assuming the interfacial thermal conductance of diamond {1 1 1} surfaces (h111) is lower than 1 × 105 W/m2 K or higher than 1 × 109 W/m2 K, the total thermal conductivity is dominated by the interfacial thermal conductance of diamond {1 0 0} surfaces (h100); while, h111 ranges from 1 × 105 W/m2 K to 1 × 109 W/m2 K, the combined effect of h111 and h100 on thermal conduction behaviour of composites can not be ignored. Furthermore, although the carbide coating on the diamond leads to an extra interfacial thermal barrier resistance on {1 0 0} diamond faces, the mean interfacial thermal conductance of the composites is improved, resulting in the increase of total thermal conductivity of the composite.