High Temperature Steam Oxidation of Laser Powder Bed Fusion Printed Stainless Steel

Nuclear reactor core materials degrade due to harsh environment exposure. Integrated computational materials engineering is a potential low-cost, accelerated route to qualifying additive manufactured parts; additive manufacturing in turn produces near-net-shape reactor components at low cost, without weakened weld sites. In this study, cylindrical samples were printed by laser powder bed fusion (LPBF) with in situ spatter imaging at low, standard, and high laser energy, with half of the samples printed with crescent-shaped shields to promote soot accumulation and spattering. X-ray tomography was done to observe porosity. The samples were subsequently sectioned into discs, and exposed to steam at 800°C for 12 hours in a simultaneous thermal analyzer to undergo oxidation, during which mass gain was recorded. Scanning electron microscopy, energy dispersive X-ray spectroscopy and Raman spectroscopy were used to characterize pores and composition of the oxidized samples. Samples printed with low laser energy were found to have highest porosity and oxidation, and higher instances of advanced oxide formation. Presented here are plots of sample surfaces using analyzed area under Raman intensity peaks for oxides Cr₂O₃, Fe₂O₃, and Fe₃O₄. This data has the potential to be used for teaching an AI machine-learning algorithm that may predict oxide formation in future LPBF samples.