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 |
Microstructural Evolution of Borides at 850°C in a Polycrystalline Superalloy and Implications on Creep Performance |
Author(s) |
Lola Lilensten, Aleksander Kostka, Sylvie Lartigue-Korinek, Baptiste Gault, Sammy Tin, Stoichko Antonov, Paraskevas Kontis |
On-Site Speaker (Planned) |
Paraskevas Kontis |
Abstract Scope |
The microstructural evolution of Cr-rich intergranular borides after creep at 850°C/185MPa and annealing at 850°C for approximately 3000h in a polycrystalline nickel-based superalloy has been studied. Scanning electron microscopy revealed the coarsening of borides, with the borides after creep exhibiting the largest thickness (800–1100 nm), compared to those annealed without an external applied load (400–600 nm). The coarsened borides were systematically found to contain a very high density of planar faults, as observed by transmission electron microscopy. Borides were found to have either a tetragonal I4/mcm, or an orthorhombic Fddd structure, with those two structures coexisting in a single particle. Finally, atom probe tomography has shown a correlation of chemical fluctuations of B and Cr with the planar faults, while partitioning of Ni and Co at dislocations within the borides after creep was also found. Ramifications of coarsened borides on the creep performance of polycrystalline superalloys will be presented. |
Proceedings Inclusion? |
Planned: |