b'Effect of oxide inclusionsInnovative solution quantifies oxide inclusions effects on the on the mechanicalmechanical properties of additive manufactured alloys.properties of additivelyI nterest has been growing in applying additive manufacturing technology to create nuclear power components with enhanced performance and reduced lead manufactured stainless steel time and cost. Among various corrosion resistant alloys, additive manufactured stainless steel 316L has attracted particular attention because it is a widely used structural material in light water reactors and an important candidate material for the advanced nuclear reactors. One unique feature of additive manufactured stainless steel is the presence of a large amount of oxide inclusions in the as-printed alloy substrate. Thermodynamic calculations showed that these oxides are metastable PROJECT NUMBER:rhodonite (MnSiO 3 ), so their size and distribution can continuously evolve over 22P1071-022FP time. The calculations were validated by the characterization of as-printed stainless steel 316L and the same alloy annealed at 900-1200C. The role of oxide inclusions TOTAL APPROVED AMOUNT:on the mechanical properties of additive manufactured stainless steel 316L was $125,000 over 1 year investigated by leveraging the small-scale tensile testing capability recently PRINCIPAL INVESTIGATOR:developed at INL. This approach enabled accurate examination of the effect of Yachun Wang oxide inclusions on the mechanical properties of additive manufactured stainless steel, which would not have been possible otherwise due to the overwhelming CO-INVESTIGATORS: interference of porosity. The results from the small-scale mechanical property testing Gerald Frankel, The Ohio State University were compared to large scale experiments. It was found that both oxide inclusions Xiaolei Guo, The Ohio State University and porosity have substantial effects on the mechanical properties of additive manufactured stainless steel. Annealing the as-printed additive manufactured stainless steel at 1000C in an argon environment for 1 hour appears to improve the strength and ductility substantially. The strengthening effect seems to be associated with the redistribution of oxide inclusions within the alloy substrate and the nano-twinning and high density of stacking faults found in the alloy matrix. The results obtained through this study will guide the manufacturing and processing of nuclear power components through the state-of-the-art additive manufacturing technology and greatly benefit multiple programs for nuclear energy development.106'