Pitting corrosion studies on functionally graded Inconel 825-SS316L wall manufactured by wire arc additive manufacturing

This research article addresses the pitting corrosion resistance of FGM walls fabricated by the Wire Arc Additive Manufacturing (WAAM). The wall is created by layer-by-layer transfer of molten metal in an uninterrupted manner with little heat input using the CMT process. Pitting corrosion tests were carried out as per the ASTM G48-11 standard on the specimens extracted from Inconel 825, FGM interfaces, and SS316L regions of the wall. The specimens were immersed in the ferric chloride hexahydrate solution for 24, 48, and 72 h. It was found that the FGM interface and the specimens made of Inconel 825 were more resistant to corrosion than the SS316L specimens. The weight loss is measured as 0.462 g, 0.1087 g, and 0.1349 g for the SS316L, FGM interface, and Inconel 825 specimens, respectively. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were used to analyze the corrosion products at the corrosion pit. The order of the pitting corrosion resistance of the specimens extracted from the FGM wall was: FGM interface > Inconel 825 > SS316L.