About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Chemistry and Physics of Interfaces
|
| Presentation Title |
Grain Boundary Phase Transitions Enable Diffusionless Climb of Disconnections |
| Author(s) |
Md Sharier Nazim, Giacomo Po, Nikhil Admal |
| On-Site Speaker (Planned) |
Md Sharier Nazim |
| Abstract Scope |
Dislocation–grain boundary interactions, including absorption, emission, and reflection, govern the mechanical response, such as strength, ductility, fracture, and microstructural evolution of polycrystalline materials. Grain boundaries possess intrinsic configurational degrees of freedom, known as GB microstates, arising from their atomic structures, can also strongly influence their properties.
Using bicrystallography and molecular dynamics simulations, we investigate the interaction of shear dislocation loops with the Σ 123<110> symmetric tilt grain boundary in Al. We show that dislocation absorption generates a mobile extrinsic disconnection with a nonzero climb component that propagates conservatively along the interface without any long-range bulk diffusion. Its motion is accompanied by a localized GB phase transformation mediated by cooperative atomic rearrangements within the GB core, producing successive metastable GB microstates. These observations establish a direct coupling between lattice dislocations and GB phase evolution and reveal a conservative mechanism for disconnection climb fundamentally distinct from conventional diffusion-mediated climb. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
ICME, Computational Materials Science & Engineering, Thin Films and Interfaces |