Abstract
Oxidation resistant overlay coatings protect the underlying superalloy component in industrial gas turbines from oxidation attack. Rate of depletion of the Al-rich β-phase in the bond coat governs the lifetime of these coatings. The applicability of a computational method in accelerating the development of corrosion resistant coatings and significantly reducing the extensive experimental effort to predict coating lifetimes and microstructural changes in three-coated Ni-based superalloys for real operational durations (20–40 kh) was undertaken in the present study. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and electron microprobe analysis (EPMA) were employed to characterize MCrAlY-coated superalloy substrates (1483, 247 and X4) after exposure at 900 °C in air + 10% H2O for up to 20,000 h. The model predicted the longest coating lifetime for the coating on X4 substrate. Precipitation of γ′ in the coatings was correctly predicted for all three coating systems. Additionally, the model was able to predict the formation of topologically close packed (TCP)-phases in the investigated coating systems.
| Original language | English |
|---|---|
| Title of host publication | Superalloys 2020 - Proceedings of the 14th International Symposium on Superalloys |
| Editors | Sammy Tin, Mark Hardy, Justin Clews, Jonathan Cormier, Qiang Feng, John Marcin, Chris O'Brien, Akane Suzuki |
| Publisher | Springer Science and Business Media Deutschland GmbH |
| Pages | 824-833 |
| Number of pages | 10 |
| ISBN (Print) | 9783030518332 |
| DOIs | |
| State | Published - 2020 |
| Event | 14th International Symposium on Superalloys, Superalloys 2021 - Seven Springs, United States Duration: Sep 12 2021 → Sep 16 2021 |
Publication series
| Name | Minerals, Metals and Materials Series |
|---|---|
| ISSN (Print) | 2367-1181 |
| ISSN (Electronic) | 2367-1696 |
Conference
| Conference | 14th International Symposium on Superalloys, Superalloys 2021 |
|---|---|
| Country/Territory | United States |
| City | Seven Springs |
| Period | 09/12/21 → 09/16/21 |
Funding
Acknowledgements G. Garner assisted with the experimental work at ORNL. T. Lowe and M. Romedenne are thanked for helping with microstructural characterization. This research was sponsored by the U. S. Department of Energy, Office of Fossil Energy, Advanced Turbine Program (R. Dennis program manager). The authors would like to thank K. Murphy at Howmet and A. Kulkarni at Siemens for providing superalloys. G. Garner assisted with the experimental work at ORNL. T. Lowe and M. Romedenne are thanked for helping with microstructural characterization. This research was sponsored by the U. S. Department of Energy, Office of Fossil Energy, Advanced Turbine Program (R. Dennis program manager). The authors would like to thank K. Murphy at Howmet and A. Kulkarni at Siemens for providing superalloys. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/ downloads/doe-public-access-plan).
Keywords
- Gas turbines
- Lifetime modeling
- Overlay coatings