Enhanced corrosion resistance of additively manufactured stainless steel by modification of feedstock

Additive manufacturing (AM) is an emerging technology to produce engineering components. However, the major challenge in the practical application of AM is the inconsistent properties of additively manufactured components. This research presents a strategy of feedstock modification to improve the corrosion performance of selective laser melted (SLM) 316L stainless steel (SS). Modified feedstock powders were produced by ball-milling of commercial-316LSS powder with 1wt.% chromium nitride (CrN). The SLM coupons produced from modified feedstock powders (SLM-316L/CrN) exhibited significantly improved corrosion performance, as evident from the high pitting and repassivation potentials and absence of metastable pitting. The microstructural characterization revealed fine oxide-inclusions comprising Si, Mn, and S in SLM-316L and only Si and Mn in SLM-316L/CrN. The absence of sulfur-containing oxide-inclusions in SLM-316L/CrN and refined cellular structure, and the change in chemical composition were attributed to corrosion resistance enhancement due to the CrN addition.