The role of carbon on the occurrence of grain boundary serration in an AISI 316 stainless steel during aging heat treatment

To investigate the effect of carbon on grain boundary serration, three kinds of the 316 stainless steels with different carbon content are used for this experiment. It was observed that the higher the carbon contents, the more the fraction of grain boundary serration. Therefore, it may be concluded that grain boundary serration is affected by the carbon contents. In addition, grain boundary is serrated prior to the formation of the carbides. To obtain the direct evidence of the effect of carbon on the occurrence of grain boundary serration, the sample with the lowest carbon content is carburized to increase carbon content. It is observed that grain boundary is considerably serrated after carburizing. These facts indicate that grain boundary serration is strongly influenced by carbon contents. It is suggested that carbon is major alloying element to accelerate the occurrence of grain boundary serration in AISI 316 stainless steel.