Role of different additives on microstructure and corrosion performance of additively manufactured 316L stainless steel alloy

Selective laser melting (SLM) is a popular powder bed fusion - additive manufacturing (PBF-AM) technique used to fabricate complex 3D components layer-by-layer. The corrosion performance of SLM printed 316L Stainless steel (SLM-316L) was often reported inconsistent in the literature. This research presents a strategy of feedstock modification to improve the corrosion performance of SLM-316L. The feedstock was modified via high energy ball milling of specific additive and 316L Stainless steel powder, and the collected composite powders were selectively laser melted. Different additives have been explored that can improve the corrosion performance of SLM-316L. Additives that could not distribute themselves in the 316L alloy matrix were segregated and showed localized corrosion adjacent to the segregations, whereas the additive that distributed itself showed significantly improved corrosion performance as evaluated by high breakdown and repassivation potential and absence of metastable pitting. The improved corrosion performance of SLM-316L-additive was correlated with microstructural changes, modified chemical composition, and passive film characteristics.