About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Magnetism and Magnetic Materials
|
| Presentation Title |
Supercritical Martensitic Phase Transformations for Ferromagnetic Shape Memory Alloys |
| Author(s) |
Timothy Thompson, Abdulhamit Sarac, Sangwon Lee, Amlan Das, Fei Xiao, Ashley Bucsek |
| On-Site Speaker (Planned) |
Timothy Thompson |
| Abstract Scope |
Many multiferroics, including various ferromagnetic shape memory alloys (FSMAs), owe their unique functionality to reversible martensitic phase transformations. Recent research indicates that, in a supercritical thermodynamic state, the phase transformation occurs through a gradual distortion of the crystal lattice without any phase interfaces. Consequently, supercritical FSMAs exhibit exceptional reversibility and low hysteretic or “anhysteretic” behaviors, despite up to 15% recoverable deformation. We use in-situ X-ray microscopy characterization (near-field and far-field high-energy diffraction microscopy), in-situ optical microscopy (differential interference contrast), and ex-situ transmission electron microscopy on Ni-Fe-Ga-Co FSMAs to reveal the systematic differences between martensitic phase transformations in subcritical and supercritical states, shifting from distinct phases with sharp interfaces to smoothly blended phases without interfaces. We enrich these observations using explanations involving the Landau theory of phase transitions to develop a unified understanding of supercritical behavior in multiferroics, informing future strategies for designing advanced multiferroic materials with exceptional functional properties. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Energy Conversion and Storage, Ceramics |