The influence and the mechanism of the precipitate/austenite interfacial C-enrichment on the intergranular corrosion sensitivity in 310 S stainless steel

•A C-enriched zone was found at the M23C6/austenite interface of 310S.•The C-enrichment was related to the intergranular corrosion sensitivity of 310S.•A mechanism of intergranular corrosion involved C-enrichment was proposed.

In this study, the intergranular corrosion behavior of 310 S stainless steels after sensitizing at different temperatures were investigated. The chemical content and the Volta potential distribution at the M23C6/austenite interface were analyzed. It is found that the sensitization of 310 S increased significantly with increasing aging temperature, although no obvious variations of the Cr-depletion level or the Volta potential difference at the M23C6/austenite interface could be observed. However, an obvious carbon-enriched zone was observed at the M23C6/austenite interface. A probable mechanism about the correlation between the sensitization of 310 S and the carbon-enrichment was proposed.