Linking early stages viscous flow sintering mechanics to elastic properties in silica glass: A multiscale DEM-FEM framework

Understanding the interactions between processing, microstructure, and properties during sintering is required for designing materials with tailored functionalities. This study validates a Discrete Element Method (DEM) model for viscous flow sintering of silica glass, focusing on microstructural evolution and effective elastic property prediction. Microstructures at various sintering stages were reconstructed in 3D using neural networks applied to FIB-SEM imaging. A quantitative comparison between the DEM-simulated microstructures and these 3D reconstructed microstructures confirm the model’s robustness to capture densification. The validated DEM microstructures were employed as Representative Volume Elements (RVEs) for Finite Element Method (FEM) simulations to compute the effective Young’s modulus. The numerical predictions align with experimental measurements for the intermediate sintering stage (relative density > 0.8). The stiffness overestimation observed during the initial consolidation phase (relative density < 0.7) is attributed to the continuous representation of the granular network and boundary condition effects. This coupled DEM-FEM methodology bridges discrete particle-level mechanics with macroscopic material performance, providing a predictive framework to assist the mechanical design of sintered materials.