The importance of grain size relative to grain boundary character on the sensitization of metastable austenitic stainless steel

Austenitic stainless steel (AISI 304L), which was thermomechanically processed by introducing cold deformation followed by annealing, was sensitized. The percentage of coincident site lattice boundaries did not correlate well with the degree of sensitization (DOS). The material with grain sizes below 10 μm was found to be the least sensitized, while specimens with larger grains showed an increase in DOS with sensitization time. The DOS is shown to have an inverse correlation with the grain boundary area, decreasing exponentially with increasing grain boundary surface area.