Surface co-segregation of minor alloying elements in Ti-modified stainless steel studied by Auger electron spectroscopy

Surface segregation of alloying elements in Ti-modified stainless steel, D9, upon thermal annealing has been studied using Auger electron spectroscopy. Minor alloying elements viz., P, S, N and Ti were found to segregate to the surface between 670 and 970 K. The influences of pre-annealing thermo-mechanical treatments on the surface segregation behaviour of various elements are presented and their implications are discussed. Cold working was observed to increase the extent of surface segregation. Nitrogen and titanium were found to be co-segregating with carbon and maximum segregation was observed for the cold-worked sample. This observation correlates well with the known secondary TiC precipitation stage, occurring in the cold worked Ti-modified stainless steels.