About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Chemistry and Physics of Interfaces
|
| Presentation Title |
Kinetic pathways of grain boundary amorphization in nanocrystalline alloys revealed by ultrafast nanocalorimetry |
| Author(s) |
William S. Cunningham |
| On-Site Speaker (Planned) |
William S. Cunningham |
| Abstract Scope |
Grain boundary amorphous interfacial phases stabilize nanocrystalline alloys and enhance performance, yet the kinetic pathways governing their formation remain insufficiently resolved. We investigate order–disorder transformations at grain boundaries in Al–Ni, Al–Y, Al–Ni–Y, and Al–Mg–Y nanocrystalline systems using ultrafast differential scanning calorimetry to capture transformation temperatures and transition kinetics across varied heating and cooling rates. Correlative electron microscopy links calorimetric signatures to structural evolution, while isothermal annealing experiments quantify disorder-to-order transformation rates. Systematic variation of cooling rates establishes critical conditions to kinetically retain amorphous grain boundary structures, and repeated rapid thermal cycling up to 1000 cycles at homologous temperatures above 0.90 demonstrates the resilience of these interfacial states in preserving ultrafine grain sizes. Thermodynamic considerations define the driving force for interfacial disordering, but our results highlight the dominant role of kinetics in governing phase stability and support defect-engineered strategies for designing robust nanocrystalline alloys. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Characterization, Aluminum |