Investigation on Critical Microstructure Size for Numerical Analysis of Metal-Matrix Composites with Network Reinforcement Architecture

Finite element method (FEM) is a powerful tool to predict the properties and reveal the mechanisms of metal-matrix composites (MMCs) with very complex architectures and novel microstructures. Recent studies have demonstrated the effectiveness of network reinforcement architectures on simultaneous strengthening and toughening. Here, as a key factor in modeling network architecture, the critical microstructure size was studied via FEM. We found that a critical microstructure size of 23 μm (cell count ∼20) existed in the FEM model, beyond which the crack deflection may be feasibly induced from particle-rich to matrix regions, leading to crack propagation in the ductile matrix cells and thus high strength and elongation. While, with cell size 20-23 μm in SiC/6061Al model, the composite strength and elongation remained intact, implying that the maximal microstructure size is 23 μm for effective network architecture simulations.