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Stability of High Energy Faults in Ni-Based SuperalloysHigh energy faults generated by lattice dislocations entering the strengthening precipitates of Ni-based superalloys are at the core of unique mechanical properties of these structural materials. Since the energies of the anti-phase boundary (APB) and complex stacking fault (CSF) can be increased by appropriate alloying additions, multiple research studies investigated this topic (e.g., such elements, as Ta, Nb and Ti were shown to increase the APB energy most effectively). However, the question about the stability of these defects has not received the attention it deserves. If they can transform spontaneously into lower energy structures, then the strengthening effect of the precipitates will be compromised. Using atomistic simulations, we found that the APB can spontaneously transform into super intrinsic stacking fault (SISF) and the CSF can spontaneously transform into L12 lattice structure. We demonstrate that Nb solutes produce very different effects in two considered transformation cases: addition of Nb increases the temperature of spontaneous APB → SISF transformation, and decreases the temperature of spontaneous CSF → L12 transformation. These results provide a different perspective on the processes vital to fascinating mechanical properties of Ni-based superalloys.
Document ID
20250000206
Acquisition Source
Ames Research Center
Document Type
Presentation
Authors
Valery Borovikov
(KBR (United States) Houston, Texas, United States)
Mikhail Mendelev
(Ames Research Center Mountain View, United States)
Timothy Smith
(Glenn Research Center Cleveland, United States)
John Lawson
(Ames Research Center Mountain View, United States)
Date Acquired
January 7, 2025
Subject Category
Metals and Metallic Materials
Meeting Information
Meeting: The Minerals, Metals & Materials Society 154th Annual Meeting and Exhibition (TMS 2025)
Location: Las Vegas, NV
Country: US
Start Date: March 23, 2025
End Date: March 27, 2025
Sponsors: American Institute of Mining, Metallurgical, and Petroleum Engineers, Minerals Metals and Materials Society
Funding Number(s)
PROJECT: ISRDS-3 80ARC020D0010
Distribution Limits
Public
Copyright
Public Use Permitted.
Technical Review
NASA Peer Committee
Keywords
Ni-based superalloys
High energy superlattice faults
Spontaneous transformations
Effects of alloying elements
Atomistic modeling
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