A mesoscale phase-field model of intergranular liquid lithium corrosion of ferritic/martensitic steels
A phase-field model is developed to simulate intergranular corrosion of ferritic/martensitic steels
exposed to liquid lithium. The chromium concentration of the material is used to track the mass
transport within the metal and liquid (corrosive) phase. The framework naturally captures intergranular
corrosion by enhancing the diffusion of chromiumalong grain boundaries relative to the grain bulk with
no special treatment for the corrosion front evolution. The formulation applies to arbitrary 2D and 3D
polycrystalline geometries. The framework reproduces experimental measurements of weight loss
and corrosion depth for a 9 wt% Cr ferritic/martensitic steel exposed to static lithium at 600 °C. A
sensitivity analysis, varying near-surface grain density, grain size, and chromium depletion thickness,
highlights the microstructural influence in the corrosion process. Moreover, the significance of
saturation is considered and evaluated. Simulation results show that near-surface grain density is a
deciding factor, whereas grain size dictates the susceptibility to intergranular corrosion.