1. Ultraslow calorimetric studies of the martensitic transformation of NiFeGa alloys: detection and analysis of avalanche phenomena.
- Author
-
Martín-Olalla, José-María, Vidal-Crespo, Antonio, Romero, Francisco Javier, Manchón-Gordón, Alejandro F., Ipus, Jhon J., Blázquez, Javier S., Gallardo, María Carmen, and Conde, Clara F.
- Subjects
MARTENSITIC transformations ,ALLOY analysis ,MARTENSITE ,THERMAL properties ,CALORIMETERS - Abstract
We study the thermal properties of a bulk Ni 55 Fe 19 Ga 26 Heusler alloy in a conduction calorimeter. At slow heating and cooling rates ( ∼ 1 K h - 1 ), we compare as-cast and annealed samples. We report a smaller thermal hysteresis after the thermal treatment due to the stabilization of the 14 M modulated structure in the martensite phase. In ultraslow experiments ( 40 mK h - 1 ), we detect and analyze the calorimetric avalanches associated with the direct and reverse martensitic transformation from cubic to 14 M phase. This reveals a distribution of events characterized by a power law with exponential cutoff p (u) ∝ u - ε exp (- u / ξ) where ε ∼ 2 and damping energies ξ = 370 μ J (direct) and ξ = 27 μ J (reverse) that characterize the asymmetry of the transformation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF