Corrosion behavior of 316L stainless steel manufactured by laser powder bed fusion (L-PBF) in an alkaline solution

Abstract

This study investigates the microstructure and electrochemical behavior of 316 L processed through laser powder bed fusion (L-PBF) and the related commercial wrought counterpart in the concrete pore solution (0.9 M NaOH + 0.9 wt% NaCl). Analyses showed that the L-PBF method did not decline the corrosion resistance of 316L SS in the alkaline solution. Even in some cases, L-PBF processed alloy showed better electrochemical behavior compared the wrought alloy. Microscopy evaluation indicated that L-PBF processed specimen showed an ultrafine cellular/columnar structure with the more uniform morphology at the higher magnifications compared to the wrought sample, possibly because of the excessive cooling rate of the L-PBF process. Besides, electrochemical studies revealed that corrosion current density related to the L-PBF processed sample reported about one-third of wrought counterpart. Also, L-PBF processed alloy identified the lower defect density compared to the wrought one. The better corrosion performance of the L-PBF processed 316L SS could be related to the fabrication method of the additively manufactured samples, which hindered the presence of detrimental phases and more stability of the passive film.