Effect of grain size and grain boundary type on intergranular stress corrosion cracking of austenitic stainless steel: A phase-field study

A phase-field model coupled with polycrystalline microstructure is utilized to investigate the effect of grain size and grain boundary types on intergranular stress corrosion cracking in austenitic stainless steels. Considering the dilute solution environment, the free energy density of the two phases is hypothesized to be in parabolic form. The slower corrosion crack propagation rate in coarse-grained microstructures can be attributed to a higher frequency of transgranular cracking. Low-angle grain boundaries can effectively deflect intergranular corrosion cracks into grains with lower corrosion susceptibility, thereby impeding crack propagation. Twin boundaries mitigate corrosion crack propagation by reducing potential initiation sites.