About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Multi-Principal Element Alloys V: Mechanical Behavior
|
| Presentation Title |
The Interplay of Anharmonicity and Chemical Order in Governing the Temperature-Dependent Stacking Fault Energetics of CoCrNi |
| Author(s) |
Reza Namakian, Fei Shuang, Thomas D Swinburne, Poulumi Dey, Wei Gao |
| On-Site Speaker (Planned) |
Reza Namakian |
| Abstract Scope |
The temperature-dependent mechanical behavior of multi-principal-element alloys is governed by a complex interplay of thermal vibrations and chemical order. However, the exact roles of these effects on stacking-fault energetics remain debated. Using fully anharmonic atomistic simulations with a neural network potential, we deconvolve these influences in equiatomic CoCrNi. Our simulations first overturn the established harmonic paradigm: including anharmonicity causes the intrinsic (ISFFE) and unstable (USFFE) stacking-fault free energies to decrease with increasing temperature. We then demonstrate that the long-standing negative-ISFFE discrepancy is resolved by local chemical order (LCO), which induces a large, positive ISFFE sufficient to stabilize a finite stacking-fault width. This result is validated with large-scale dislocation simulations. Our findings establish a new, physically grounded framework for predicting deformation in CoCrNi, proving that both anharmonicity and chemical order are essential components for accurate computational models. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Entropy Alloys, Mechanical Properties, Modeling and Simulation |