Sepehri-Amin, H. ; Taubel, A. ; Ohkubo, T. ; Skokov, K. P. ; Gutfleisch, O. ; Hono, K. (2018)
Microstructural origin of hysteresis in Ni-Mn-In based magnetocaloric compounds.
In: Acta Materialia, 147
doi: 10.1016/j.actamat.2018.01.044
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Microstructures of magnetocaloric Ni-Mn-In-based Heusler alloys, Ni50.2Mn35.0In14.8 and Ni46.1Mn37.9Fe3.0In13.0, were studied to understand the origin of a large difference in thermal hysteresis in these two alloys. In-situ transmission electron microscopy (TEM) observation showed that the Fe containing sample with a large hysteresis shows a discontinuous phase transition due to the existence of nano-scale Fe-rich bcc phase, along with Fe-lean B2 and L21 phases in the austenite state. The Fe-free sample with a low hysteresis shows a uniform phase transition from martensite to austenite initiated by the nucleation of austenite at the twin boundaries. Ni segregation was found at the twin boundaries of the low hysteresis sample that is considered to facilitate the nucleation of the austenite. The phase transition progresses by the growth of the nucleated austenite to the neighboring twins. 5M and 7M modulated martensites in the low hysteresis sample give rise to a slight difference in the phase transition temperatures in the twin bands contributing to the small hysteresis of 4.4 K in the Fe-free sample. Based on these results, we conclude that to minimize the thermal hysteresis of the Ni-Mn-In based magnetocaloric compounds, one of the key factors is to achieve a uniform composition and crystal structure in the alloy.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2018 |
| Autor(en): | Sepehri-Amin, H. ; Taubel, A. ; Ohkubo, T. ; Skokov, K. P. ; Gutfleisch, O. ; Hono, K. |
| Art des Eintrags: | Bibliographie |
| Titel: | Microstructural origin of hysteresis in Ni-Mn-In based magnetocaloric compounds |
| Sprache: | Englisch |
| Publikationsjahr: | 1 April 2018 |
| Verlag: | Elsevier Science Publishing |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Acta Materialia |
| Jahrgang/Volume einer Zeitschrift: | 147 |
| DOI: | 10.1016/j.actamat.2018.01.044 |
| URL / URN: | https://doi.org/10.1016/j.actamat.2018.01.044 |
| Kurzbeschreibung (Abstract): | Microstructures of magnetocaloric Ni-Mn-In-based Heusler alloys, Ni50.2Mn35.0In14.8 and Ni46.1Mn37.9Fe3.0In13.0, were studied to understand the origin of a large difference in thermal hysteresis in these two alloys. In-situ transmission electron microscopy (TEM) observation showed that the Fe containing sample with a large hysteresis shows a discontinuous phase transition due to the existence of nano-scale Fe-rich bcc phase, along with Fe-lean B2 and L21 phases in the austenite state. The Fe-free sample with a low hysteresis shows a uniform phase transition from martensite to austenite initiated by the nucleation of austenite at the twin boundaries. Ni segregation was found at the twin boundaries of the low hysteresis sample that is considered to facilitate the nucleation of the austenite. The phase transition progresses by the growth of the nucleated austenite to the neighboring twins. 5M and 7M modulated martensites in the low hysteresis sample give rise to a slight difference in the phase transition temperatures in the twin bands contributing to the small hysteresis of 4.4 K in the Fe-free sample. Based on these results, we conclude that to minimize the thermal hysteresis of the Ni-Mn-In based magnetocaloric compounds, one of the key factors is to achieve a uniform composition and crystal structure in the alloy. |
| Freie Schlagworte: | Hysteresis, Magnetocaloric, Heusler alloys, Microstructure, In-situ TEM |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Funktionale Materialien |
| Hinterlegungsdatum: | 12 Mär 2018 09:54 |
| Letzte Änderung: | 31 Jan 2019 15:12 |
| PPN: | |
| Sponsoren: | This work was in part supported by LG electronics., OG and AT acknowledge the support by DFG SPP 1599 and helpful discussion with Max Fries and Tino Gottschall. |
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