Microstructure and Creep Performance of Direct Single-Step Aged Gas Metal Arc Directed Energy Deposition Processed Haynes 282

Abstract There is a need to rapidly produce large components for power generation technologies to reduce plant down time. Directed energy deposition processes can provide the high deposition rates needed to rapidly produce large components, but the microstructures and resulting high-temperature mechanical properties must be understood. In this work, a gamma prime ( γ ′) strengthened nickel-based alloy, Haynes 282, was processed with gas metal arc directed energy deposition (GMA-DED), and direct single-step aged at 800 °C for 8 hours before creep testing at 760 °C. The builds exhibited large columnar grains elongated parallel to the build direction and variations in γ ′ size and distribution throughout the dendritic structure. Samples tested parallel to the build direction showed lower minimum creep rates and long creep lives compared to samples tested perpendicular to the build direction, but the overall creep performance of GMA-DED samples was comparable to that of wrought Haynes 282. Failed GMA-DED creep samples exhibited a unique combination of intergranular creep voids as well as transgranular creep fracture associated with gamma prime depletion along glide planes. This work shows that GMA-DED is a viable route to produce structural components, but further work is needed to better understand creep deformation and fracture mechanisms.