High-Temperature Mechanical Behavior of Additvely Manufactured Gas Turbine Alloys

Monday, September 13, 2021: 2:20 PM
230 (America's Center)
Dr. John Shingledecker, Ph.D., FASM , Electric Power Research Institute, Charlotte, NC
Alex Bridges , Electric Power Research Institute, Charlotte, NC
Additive manufacturing (AM) of higher γ' volume fraction nickel-based superalloys continues to progress with industrial companies and machines demonstrating the ability to now repeatably make crack-free nearly 100% dense parts. This open the opportunity to utilize AM for hot-section components in power generation gas turbines. By using different powder chemistries, different AM processes, and process control, it is also possible to tailor specific microstructures features. While research is rapidly progressing the processing and microstructure relationships for these superalloys, there exists a very limited amount of high-temperature data to compare to traditional castings, directionally solidified materials, and wrought alloys. Specifically, it is unclear how AM superalloys behave in creep relative to castings. In this work, EPRI is collaboratively evaluating the creep performance of commercially produced nickel-based superalloys of different compositions and processing condition. Partners in this work include national laboratories, equipment manufacturers, and universities. Early results show that while the grain size of the AM produced materials are finer than the cast equivalents, the difference in grain size cannot explain all the differences in mechanical response between AM and traditionally produced gas turbine components. The presentation will describe some of the detailed characterization performed to identify other factors such as chemistry and precipitate size and location which may be influencing high-temperature material behavior including long-term creep-rupture.