This study investigates the influence of sigma phase in 446 stainless steel on pitting process in a Br- environment after heat treatment, as well as its relationship with (Ti, Nb) primary precipitates. We find that the chemical dissolution of (Ti, Nb) primary precipitates takes top priority, while the formation of stable pitting tends to occur around sigma phase at the depletion region with size wider than at least 1.5μm. Furthermore, the mesh-like sigma phase along grain boundaries limits the lateral growth of pitting on the surface, while increasing the tendency for vertical growth, eventually forming a mesh-like pitting morphology.

This content is only available as a PDF.
You do not currently have access to this content.