Peridynamic Modeling of Intergranular Corrosion Damage

Abstract

A new peridynamic (PD) model for Intergranular corrosion (IGC) damage is presented. The model can simulate conditions ranging from grain boundary-only corrosion to full grain dissolution. Compared with other models, we require minimal input data for calibration: Tafel kinetics and electrolyte diffusion coefficient. Once calibrated, the PD model predicts, quantitatively, the penetration depth of the corrosion front as well as the morphology of the corroded microstructure in AA2024-T3 exposed to NaCl solution. We note that, when grain dissolution is negligible over hours, the diffusion controlled assumption gives results that match well the experimental observations. Tests for anisotropic microstructures confirm the direction dependency of corrosion penetration in rolled AA2024-T3 sheets. Without any other changes to the model, increasing the applied potential leads to partial and full grain dissolution. The PD model introduced here can be applied to any polycrystalline alloy.