A Numerical Study of the Microstructure-Dependent Thermal Conductivity of Diamond-Reinforced Sintered Silver...

Diamond-reinforced sintered silver composites are considered promising thermal interface materials (TIMs) for power electronic packaging due to their combination of high thermal conductivity and mechanical reliability. This paper proposes and validates a numerical homogenization framework based on three-dimensional representative volume elements (RVEs) and steady-state finite element method (FEM) simulations to predict the effective thermal conductivity (k_eff) of silver-diamond composites containing randomly distributed diamond particles and pores. Using a microstructure generation algorithm based on Gaussian random fields (GRF), a parametric study comprising 180 simulations was systematically conducted, covering variables such as porosity (10-50%), particle size (1-9 voxels), spatial distribution parameter σ, and diamond content. The results indicate that porosity is the dominant factor affecting k_eff; within the studied parameter space, increasing porosity from 10% to 50% leads to a significant decrease in k_eff (approximately 40% in representative samples). Increasing diamond content significantly enhances k_eff under low-porosity conditions, but the benefit diminishes at high porosity levels, whereas k_eff correlates positively with increasing particle size. These findings highlight the critical role of microstructure design in achieving high-performance heat dissipation and provide practical guidance for optimizing diamond-sintered silver composite TIMs. The proposed three-dimensional random microstructure generation algorithm offers a viable approach for predicting the k_eff of such composite TIMs.