About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
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Advanced Characterization Techniques for Quantifying and Modeling Deformation
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| Presentation Title |
Characterizing the Localized and Stress-Induced χ Phase Transformation in a Ni-Based Superalloy |
| Author(s) |
Ashton J. Egan, N.S. Harsha Gunda, Longsheng Feng, Maryam Ghazisaeidi, Yunzhi Wang, Sammy Tin, Michael Mills |
| On-Site Speaker (Planned) |
Ashton J. Egan |
| Abstract Scope |
This study investigates Localized Phase Transformation (LPT) in nickel-based superalloys, focusing on novel deformation pathways promoting the formation of χ and HCP nano-laths. Analysis of the deformation substructure was conducted after creep testing superalloy RRHT5, revealing that the nano-laths were associated with superlattice intrinsic stacking faults and microtwins which also exhibited LPT. Advanced characterization techniques were employed, such as electron channeling contrast imaging (ECCI), and atomic-resolution scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDS), which revealed local composition and lattice site occupancies. Center of symmetry (COS) and Burgers vector analysis further complemented the STEM observations. Additionally, density functional theory (DFT) calculations and first-principles-based Monte Carlo simulations provided insight into the formation mechanisms of the nano-laths. These analyses informed a CALPHAD-driven alloy design methodology, introducing a new design parameter describing LPT growth tendency, which is crucial for preventing undesirable bulk phase formation during computationally driven alloy development. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, High-Temperature Materials, Phase Transformations |