|About this Abstract
||2023 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||Eutectoid Ordering Morphologies in Fe-Pd and Shockley’s (Controversial?) L1’ Phase
||Adrian Savovici, William A. Soffa, Jerrold A. Floro
|On-Site Speaker (Planned)
In Fe-Pd, the microstructure resulting from eutectoid decomposition, A1 -> L10 + L12, has never been explored, despite the potential for exchange-coupled ferromagnetism. We show that thermal aging of Fe–61.8 at% Pd bulk alloys at 650C produces well-known L10 polytwins, where L12 now coexists as nm-scale lamellae by wetting both the dodecahedrally-conjugated (110) twin boundaries and the L10 anti-phase boundaries. While this is nominally consistent with prior predictions by phase field modelling, the phase evolution is non-trivial. If this alloy is instead aged at 525C, L12 disappears, and secondary basal-plane ordering produces the Shockley L1’ phase. Predictions regarding this phase have been debated over decades, and direct experimental evidence has been quite limited. Our investigations aim to understand the stability, microstructure and the nature of the phase transformation (first- vs. higher-order and the role of magnetic energy) to L1’. National Science Foundation support through grant DMR-1709914 is gratefully acknowledged.
||Magnetic Materials, Iron and Steel,