Multiscale modelling of corrosion-induced intergranular strain in iron under alkaline conditions

• Novel multiscale model upscales atomistic to finite element method, preserving grain boundary crystallography • Temporal evolution of system's electrochemical properties evaluated with nanoscale resolution • Corrosion-induced intergranular strain in an iron polycrystal is quantified • Critical microstructural factors influencing localized corrosion identified, guiding material design Intergranular corrosion in polycrystalline materials, along with the associated intergranular strain resulting from corrosion product formation, poses significant economic and structural challenges across various industries. Effectively addressing this issue requires predictive corrosion models capable of capturing atomic-scale details of the microstructure—particularly the crystallographic characteristics of grain boundaries—and their evolution over time. In this study, we present a novel multiscale modelling approach that integrates atomistic insights from reactive molecular dynamics with the computational efficiency of the finite element method, enabling realistic, large-scale simulations of corrosion-related microstructural phenomena. Using this approach, we computed corrosion-induced intergranular strain in a polycrystalline iron sample. Furthermore, we analysed the influence of microstructural features on the corrosion rate, providing insights into the temporal evolution of the system’s electrochemical characteristics.