About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Chemistry and Physics of Interfaces
|
| Presentation Title |
Soft Translation Modes and Phantom Hydrogen Traps at a Nickel Sigma 3 {112} Incoherent Twin Boundary |
| Author(s) |
Wenwu Xu, Jose Morales |
| On-Site Speaker (Planned) |
Wenwu Xu |
| Abstract Scope |
Hydrogen-trap spectra from 0 K atomistic calculations often assume that a constructed grain-boundary reference is the lowest-energy structure. Combining Ni-H embedded-atom simulations with comprehensive density-functional theory validation, we show that the conventionally minimized Sigma 3 {112} incoherent twin boundary in nickel is a fragile translation state rather than a robust reference. A density-conserving in-plane grain translation lowers the boundary energy, and interstitial hydrogen placed near, but not within, the boundary can trigger this transition during minimization. DFT calculations confirm the competing translation states and support the same structural instability, while vacancy and self-interstitial controls show that hydrogen exposes a soft translation mode rather than acting through unique chemistry. Molecular dynamics and nudged elastic band calculations indicate no durable forward barrier. These results establish a practical hazard for hydrogen-embrittlement modeling: metastable references can generate phantom traps that are boundary transformation energies, not true hydrogen binding. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Modeling and Simulation, Thin Films and Interfaces |