A statistical investigation of the effects of grain boundary properties on transgranular fracture

A two-dimensional finite-element model is developed to investigate transgranular fracture in polycrystalline alumina under tensile loading. Microcracking is modeled explicitly using the cohesive interface approach. The effects of grain boundary distributions on mesoscopic failure strength and fracture energy, and the resulting percentages of transgranular fracture are examined. Results are based on 20 different realizations of microstructures in an attempt to capture the stochastic nature of brittle failure. Numerical results indicate that the grain boundary distribution has profound effects on mesoscopically observed values, which are in part controlled by the crack propagation path. Based on observations of the simulated crack path, microstructural engineering with respect to grain morphology is conducted, leading to a significant increase in performance.