About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Chemistry and Physics of Interfaces
|
| Presentation Title |
A segregation-induced grain boundary phase transition mechanism for disconnection formation |
| Author(s) |
Zuoyong Zhang, Chuang Deng |
| On-Site Speaker (Planned) |
Zuoyong Zhang |
| Abstract Scope |
Disconnections, key mediators of grain boundary (GB) kinetics, are typically understood to nucleate via thermal or mechanical activation. Here, atomistic simulations reveal a distinct mechanism in which solute interstitial segregation alone drives disconnection formation across several substitutional binary alloys (e.g., Al–Ni, Al–Fe). In contrast to pure materials, this process occurs without a nucleation energy barrier. We identify segregation-induced GB phase transitions that produce two types of states: (i) isolated disconnections or phase junctions that enable GB migration but vanish with continued segregation, and (ii) composite disconnections formed by the coupling of two oppositely oriented isolated disconnections. These disconnections are mechanically robust, suppress shear-coupled migration, and instead promote GB amorphization and pure sliding under shear. Their long-range stress fields further attract solutes and facilitate precipitation. Verified by dichromatic pattern analysis, these features persist across chemistries and crystal structures, establishing a barrier-free pathway for disconnection formation in alloys. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Aluminum, Phase Transformations |