About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Transmutation Effects in Materials in Fission, Fusion, and Spallation Environments
|
| Presentation Title |
Effect of stress on grain boundary helium bubble coalescence in iron: An atomistic simulation study |
| Author(s) |
Silas John, Li Yang, Brian Wirth |
| On-Site Speaker (Planned) |
Silas John |
| Abstract Scope |
Molecular dynamics (MD) simulations were used to investigate the coalescence mechanisms of He bubbles at grain boundaries (GBs) in bcc Fe under constant shear stresses at temperatures between 500 K and 923 K. The results show that for temperature, stress above a threshold, bubble migrate along the GB via sliding mechanism. When two bubbles are close to each other, the coupling between GB slide, and asymmetry in GB bubbles positions promotes directional, non-uniform bubble evolution/migration, leading to coalescence. Increasing temperature and stress increases sliding rate, which in turn accelerated bubble coalescence. Notably, deformation is accommodated by coupled GB sliding and migration, with the dominant mechanism strongly influencing bubble coalescence. Specifically, coalescence was observed at Σ5 and Σ13a where sliding dominates but absent in Σ25 and Σ3 where GB migration is the dominant mechanism. In Σ25, GB edge dislocations motion suppress sliding, while high-misorientation Σ3 favors GB migration and inhibits coalescence. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Temperature Materials, Computational Materials Science & Engineering, Iron and Steel |