Quantifying the influence of porosity on the thermophysical properties of diamond/Al-alloy matrix composite utilizing Micro-CT and finite element modeling

The impact of pores on the thermophysical properties of the diamond/Al-alloy composite has been systematically investigated using numerical and experimental tests. A multi-phase representative volume element (RVE) model of the manufactured composite has been developed by utilizing the statistical data from the Micro-computed tomography (Micro-CT) scanning technology, in which a new pore shape equivalent method considering its morphology and distributions is proposed. The effective thermal conductivities (ETC) of the typically manufactured composites with the consideration of the pores and interfacial thermal conductance (ITC) have been predicted and validated by comparing with corresponding experimental results, and the average absolute discrepancy is reduced from 29.47 % for the perfect ITC cases to 10.24 % for the imperfect ITC cases. Based on the simulation results from the Finite Element Method (FEM), a quantitative analysis was conducted to reveal the effect mechanism of pores and interfaces on the heat flux density and temperature field. Furthermore, a modified theoretical model for calculating the ETC of composites containing pores was established by introducing new interaction coefficients to the Maxwell mean-field (MMF) model. The validated results indicate that the modified model improves the prediction accuracy from 53.82 % to 8.82 % for the ETC of porosity-containing composites, which also aids in expanding the scope of theoretical models for predicting the performance of composites.