Intergranular and pitting corrosion susceptibility of sensitized selective laser melted 316L stainless steel

The intergranular corrosion (IGC) and pitting corrosion behavior of selective laser melted (SLMed) 316L stainless steel (316L SS) after sensitization were systematically investigated and compared with its wrought counterpart. The results reveal that SLMed 316L SS exhibits inferior IGC resistance compared with the wrought material due to its lower proportion of Σ3 coincident-site lattice (CSL) boundaries. However, it shows significantly higher pitting corrosion resistance, which is attributed to the refinement of non-metallic inclusions. Following sensitization treatment, both materials experienced a significant reduction in pitting resistance alongside an increase in metastable pitting events. The underlying degradation mechanisms are elucidated through the analysis of preferential initiation sites and passive film composition evolution.