About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
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| Symposium
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Fundamental Science of Microstructural Evolution and Phase Transformations: An MPMD/FMD/SMD Symposium in Honor of Peter Voorhees
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| Presentation Title |
First and Second Order Magnetic Phase Transitions Tuning in La(Fe,Z,Si)13 Magnetocaloric Alloys |
| Author(s) |
Elena Priesen Reis, Kyle Hunady, Brent Fultz |
| On-Site Speaker (Planned) |
Elena Priesen Reis |
| Abstract Scope |
Magnetocaloric La(Fe,Z,Si)13 alloys have magnetic Curie transitions whose character—first- vs. second-order—can be tuned through compositional substitution where Z is Ni, Co, or a mix of the two. We report the magnetostrictive strain and magnetic critical behavior across a series of LaFe11.5-(x+y)CoxNiySi1.5 alloys to understand how these transitions evolve. Dilatometry reveals abrupt strain jumps near TC in undoped alloys, which vanish with increasing Co or Ni content, signaling a shift from first- to second-order behavior. Critical exponent analysis confirms this, with Co-rich samples approaching 3D Heisenberg scaling, while Ni-rich samples deviate from universal behavior, consistent with weakened exchange interactions and phase inhomogeneity. The existence of a tricritical point in the Co-series was found at approximately x = 0.2, beyond which mechanical energy dissipation is decreased by orders of magnitude. This reduced dissipation indicates improved thermodynamic reversibility for magnetic refrigeration applications. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Magnetic Materials, Other |