Experimental and numerical investigation of the effective thermal conductivity of MoSi2–RSiC composites with a three-dimensional interpenetrating network structure

Abstract The composition and microstructure of materials play important roles in their thermal properties. In this study, the temperature and composition dependence of the thermal conductivity of MoSi2–RSiC composites with a special 3D interpenetrating network structure was investigated experimentally and numerically. A microstructure-based model was established using serial sectioning technology. The model could describe the connectivity and distribution characteristics of the two phases in the composites. Finite element simulation could accurately predict the effective thermal conductivity of the MoSi2–RSiC composites, with a deviation of 6.8%–9.6% between numerical and experimental results at different temperatures. Furthermore, a novel simplified model was developed to predict the effective thermal conductivity of the composites with a 3D interpenetrating network structure at different network inclusions. Landauer's effective medium percolation theory (EMPT) was used to verify the numerical values and analytical results. The calculation results of EMPT and the simplified model fit well with the experimental data of the composites with a high volume fraction matrix or measured below 600 K; the former was due to the effect of matrix density on the porosity and interfacial phase content of the composites, and the latter was due to the reduced difference in thermal conductivity coefficient among SiC, MoSi2 and the interfacial phase, and air with increased temperatures.