Intergranular corrosion and grain dissolution with peridynamics

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Bobaru, Florin; Jafarzadeh, Siavash; Chen, Ziguang
Corrosion damage; peridynamics; intergranular corrosion; stress-dependent corrosion.; Engineering
abstract description
In polycrystalline material, intergranular corrosion (IGC) is a major cause for failure initiation and leads to significant reduction in strength. The sharp and narrow defects along grain boundaries induced by the corrosion damage along grain boundaries act as stress concentration sites, from which cracks can easily develop. While progress has been made on certain aspects of modeling IGC damage, it can be said that a fully predictive model is no yet available. In this work, we introduce a peridynamic (PD) model (see [1] and [2]) for IGC damage ([3]). We use mixed potential theory and mass transfer in the electrolyte to model IGC. The model considers different dissolution rates for grains and grain boundaries based on their corresponding Tafel kinetics. We validate our model quantitatively against published experiments for IGC in a AA2024 foil immersed in NaCl solution. In addition, we show that new PD model can successfully capture the combination of grain boundary corrosion and grain dissolution at higher potential values (see Fig. 1), in agreement with experimental observations. We extend the model to treat general micro-galvanic corrosion and compare our results with experimental ones.Please click Additional Files below to see the full abstract.