Finite Element Simulation of Toughening Mechanisms of Graphene-Reinforced Si₃N₄ Nanocomposites

Silicon nitride (Si₃N₄), an inherently brittle ceramic, can be toughened through the addition of reinforcing nanoparticles. Among these, graphene has emerged in the past decade as a particularly effective additive. Numerous processing strategies have been explored to optimize the toughness of graphene–Si₃N₄ nanocomposites. While experimental studies have provided valuable insights into the associated toughening mechanisms, numerical modeling based on realistic microstructural features can further advance our understanding and support the development of tougher ceramics. This study aims to simulate toughening mechanisms in graphene–Si₃N₄ nanocomposites, which are commonly observed in experiments. Microstructural parameters such as platelet length, platelet thickness, orientation distributions, and interfacial properties were incorporated into finite element models. Tensile and bending test simulations were performed. Results indicated that major toughening mechanisms—crack deflection, crack branching, separation, crack bridging, and filler pull-out—could be reproduced with the microstructure-informed models. Findings of this study will be a base for future studies on numerical models that can converge mechanical experiments.