Additively Manufactured Superalloy Turbine Components Enhanced by Directional Recrystallization for Creep-Extreme Environments

The proposed R&D project will develop a proprietary post-processing strategy for the enhancement of high temperature creep and other mechanical properties in additively manufactured (AM) Ni-based superalloy gas turbine engine hot section components produced by laser powder bed fusion (LPBF). Base effort will fully characterize relevant high-temperature mechanical properties of AM superalloy test specimens with and without the demonstrated post-processing strategy: creep, low cycle fatigue, high cycle fatigue, and hot tensile. Post-processing strategy will be developed and applied to a turbine component design relevant to the advantages of AM methods. Proposer will design and plan system requirements for exemplary component processing, then assemble and configure post-processing equipment for subsequent testing on the exemplary component. System will be evaluated during component post-processing using in-situ non-destructive techniques. Non-destructive evaluation will be used to evaluate geometry of post-processed component and conformity with target metrics. Destructive cutup and metallographic examination of the post-processed component will be used to evaluate post-processed microstructure and conformity with target metrics. Post-process method will be repeated on subsequent exemplary component samples with associated non-destructive and destructive evaluation to demonstrate repeatable conformity with target metrics. Conditions and automation of the post-processing method will be developed and reduced to practice sufficient for producing component samples with required geometry and microstructure for system-level testing in a relevant environment (TRL 6). Option effort will yield manufactured exemplary components post-processed with the final developed strategy and finished according to requirements for system-level testing in the relevant environment. Proposer will also provide manufactured exemplary components post-processed by standard methods but without the developed strategy. Final components will be delivered to the turbine testing facility at the Air Force Research Laboratory, inspected, and prepared for system-level testing. Test conditions will be relevant to operational duty cycles. Subject to initial performance and test facility advisory approval, FAA over-temperature testing will be performed. Evaluation of component performance will be performed in-situ with boroscopic inspection and system-level measurements. Post-mortem non-destructive and destructive analysis will be performed on recovered components to assess outcome, material performance, and conformity with target metrics, including creep performance improvement by at least an order-of-magnitude. Reports detailing progress and results will be presented to Program Officer each quarter. A final Phase II report and technical presentation summarizing all results, lessons learned, and potential transition path will be delivered to Program Officer at conclusion of the program.