A peridynamic model for oxidation and damage in zirconium carbide ceramics

Zirconium carbide (ZrC) has potential to be applied in next-generation nuclear reactors for space missions and industrial applications. The mechanisms controlling ZrC oxidation dependence on temperature, material composition, pressure, porosity are not fully understood. In this work, we use a peridynamic modeling of diffusion/reaction across several regions observed in previous experiments to explain the oxygen diffusion mechanism and reaction kinetics. We emphasize the importance in the oxidation and damage process of a transition layer of partially-oxidized ZrC. The peridynamic model has an autonomously moving oxidation interface, and the delamination/detachment of oxide (induced by large volumetric expansion) is simulated here with an oxygen concentration-driven damage model. Once the diffusion properties are calibrated to match the measured oxygen concentration across the oxidation front, the speed of propagation of the oxidation front is predicted by a 1D peridynamic model in excellent agreement with experimental observations. An extension to 2D finds the shape of remaining unoxidized ZrC conforming to experimental observations.