Intergranular segregation of Cr in Ti-stabilized low-Cr ferritic stainless steel

The precipitation and segregation phenomenon in a type 409L Ti-stabilized 11 wt.% Cr ferritic stainless steel has been investigated using transmission electron microscopy and a laser-assisted three-dimensional atom probe. In solution-treated and aged specimens, a strong segregation and consequent depletion of Cr was observed, as well as segregation of C and Ti atoms along the grain boundary. The reason for the Cr segregation and the way to avoid such segregation is discussed.