2018 | AFC ACCOMPLISHMENTS 82 Advances in additive manufacturing provide a pathway to a new fabrication paradigm for structural materials in advanced reactor concepts. One process, laser-powder blown DED creates these layer-by-layer components by injecting micron size powder through a nozzle into a melt pool that is created by a high-powered coaxial laser beam. The system is capable of moving in the X-,Y-, and Z-direction thus enabling a wide range of geometries to be produced.The layer-by-layer deposition of this AM technique results in a complex temperature-temporal profile for the manufactured component which can result in varying microstructural features on a range of micron and millimeter length scales.The result is a detailed study required to understand how the laser powder blown DED process generates microstructures using alloy HT9 in prototypic geometries and how these microstructures control the material properties. Accomplishments: HT9 powder feedstock was used in the fabrication of test coupons. A section of the coupons was then reserved for testing and characterization while other portions underwent a post- fabrication heat treatment.Two heat treatments were investigated, the first deemed the “FCRD” treatment which was austenitized at 1040°C for 30 minutes followed by air cooling and tempering at 760°C. The other was the “ACO3” heat treatment which was austenitized at 1065°C for 30 minutes followed by air cooling and tempering at 750°C.The as-built and the FCRD and ACO3 heat treated specimens were then tested for strength and ductility as shown in the attached figure.The samples generally showed good mechanical properties with