About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Progress Toward Mechanisms, Thermodynamics, and Kinetics of Phase Transformations: An MPMD/SMD Symposium Honoring John H Perepezko
|
| Presentation Title |
Beyond Classical Nucleation: Devitrification of Al–RE Metallic Glasses |
| Author(s) |
Eren Yunus Kalay, İlkay Kalay |
| On-Site Speaker (Planned) |
Eren Yunus Kalay |
| Abstract Scope |
Al–rare-earth marginal metallic glasses exhibit devitrification behavior, producing fcc-Al nanocrystals at number densities approaching 10²⁴ m⁻³, far beyond classical nucleation theory predictions. This work examines how medium-range order, processing history, and mechanical loading govern phase selection and nanocrystal formation in Al–RE alloys. Melt-spun and magnetron-sputtered glasses with identical compositions follow distinct crystallization pathways despite comparable short-range order, indicating that medium-range structural motifs influence nucleation. High-energy X-ray diffraction, differential scanning calorimetry, transmission electron microscopy, molecular dynamics, Voronoi analysis, Warren–Cowley parameters, and 4D-STEM are combined to resolve structural correlations from the liquid state to room temperature. In situ TEM straining reveals deformation-induced crystallization within shear bands, where fcc-Al nanocrystals with an average size of 5 nm form before fracture. These nanocrystals promote crack deflection and energy dissipation. The results support a unified picture in which medium-range order acts as a structural precursor directly controlling both thermal devitrification and mechanically activated phase transformations. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Solidification, Characterization |