About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
Analysis of the Fault Assisted hP24 Phase Transformation And Stacking Fault Energy Guided Design Strategy of a Co Based Superalloys System |
| Author(s) |
Hyun Gi Min, William Streit Cunningham, Kooknoh Yoon, Min Seok Kim, Won Seok Ko, Daniel S Gianola, Eun Soo Park |
| On-Site Speaker (Planned) |
Hyun Gi Min |
| Abstract Scope |
Co-based superalloys are considered promising candidates for high-temperature applications due to their higher cP4(γ′) solvus temperatures and superior oxidation resistance. However, their broader use has been limited by the metastability of the cP4 phase, which can lead to microstructural instability during service. While prior efforts have focused on raising the solvus temperature to improve phase stability, we observed a high-temperature diffusionless phase transformation from cP4 to the hP24 phase in a specifically designed Co-based alloy. This transformation is initiated by fault formation along (111) planar slip, indicating a defect-assisted martensitic mechanism. These results demonstrate that the metastability of the cP4 phase can be controlled by tuning the Stacking Fault Energy to suppress planar fault formation. We propose an SFE-guided design strategy to complement solvus-based design, enabling improved cP4 phase stability and creep resistance in Co-based superalloys. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Temperature Materials, Phase Transformations, Copper / Nickel / Cobalt |