About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
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Symposium
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Deformation and Damage Mechanisms of High Temperature Alloys
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Presentation Title |
Design of Cast Alumina-forming Austenitic Alloys for Extreme Environments |
Author(s) |
Yukinori Yamamoto, Michael P Brady, Govindarajan Muralidharan, James A Haynes, Arun Devaraj, Bharat Gwalani, Libor Kovarik |
On-Site Speaker (Planned) |
Yukinori Yamamoto |
Abstract Scope |
A new alloy design approach for cast, creep-resistant alumina-forming austenitic alloys is proposed, targeting the use in combustion exhaust gas environments at ≥900-950°C. Computational thermodynamics guided the alloy design to maximize the strengthening second-phase formation and promote a protective, external alumina-scale formation, which minimized the experimental iteration and accelerated the alloy design validation. An alloy based on Fe-17Cr-4Al-22Ni-Nb-C, wt.%, successfully achieved ~20 times longer creep-rupture life than chromia-forming cast austenitic steel HK30Nb (Fe-25Cr-20Ni-Nb-C base) at 900°C and 50MPa, and significantly improved oxidation resistance which maintained the surface protectiveness for more than 1,000h of cyclic exposure at 950°C in 10% water vapor containing environment. This paper will report on the results from detailed microstructure characterization correlating the creep deformation behavior with the controlled second phase precipitation within the matrix. Research sponsored by U.S. DOE, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office (VTO), Powertrain Materials Core Program. |
Proceedings Inclusion? |
Planned: |
Keywords |
High-Temperature Materials, Environmental Effects, Solidification |