Abstract
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.
Highlights
Austenitic 316L stainless (316L) has a wide range of industrial applications ranging from kitchenware to nuclear, and aerospace industries[1]
It is well known that the manganese sulfide (MnS) inclusions are the common impurities found in wrought and are the reason for pitting corrosion[4]
The absence of MnS inclusions in selective laser melting (SLM)-316L, confirmed by the Scanning electron microscopy (SEM) and Scanning transmission electron microscopy (STEM) analysis, is attributed to higher Eb than wrought-316L, which is in agreement with the literature[6]
Summary
Austenitic 316L stainless (316L) has a wide range of industrial applications ranging from kitchenware to nuclear, and aerospace industries[1]. Post-processing is performed on the SLM-316L components to eliminate the manufacturing defects and obtain improved and consistent properties. None of the studies reported improved corrosion performance of SLM-316L produced using modified feedstock. The authors hypothesize that SLM can produce highly corrosion-resistant stainless steels if the feedstock is modified using additives that suppress the formation of deleterious inclusions, homogenize microstructure, and introduce nitrogen. Test coupons produced from the modified feedstock dislocations called cellular boundaries, whereas sub-cells were (SLM-316L/CrN) showed high corrosion performance, as evident fenced by thin dislocations (interior of the cells) called sub-cellular from high pitting and repassivation potentials. A series of spherical improving corrosion performance of additively manufactured nanosized oxide-inclusions was observed at the cell boundaries alloys and merit in modifying the feedstock for improving and at the junction of sub-cell boundaries Fig. 2b. No subcell or dislocations were noticed within B-stripe regions, whereas
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
