Martensitic transformation near room temperature and hysteresis in (Ni–Co)50–Mn–Sn metamagnetic shape memory alloys

Tomoya Miyakawa, Tatsuya Ito, Xiao Xu, Toshihiro Omori, Ryosuke Kainuma

研究成果: Article査読

1 被引用数 (Scopus)


The martensitic transformation behaviors, magnetic properties, crystal structures, and entropy change (ΔS) of Ni50−xCoxMn50−ySny alloys were systematically investigated. Samples were prepared by induction melting, followed by solution heat treatment at 1273 K for 1 day and quenching. A magnetic phase diagram with a broad range of compositions was established, from which a series of alloys with varying Co concentrations was selected, such that their martensitic transformation starting temperatures (TMss) were near room temperature. The thermal and magnetic-field hystereses of these samples were systematically investigated, and a clear composition dependence was observed. The dissipation energy (Edis), which governs the transformation hysteresis, was found to be smaller for alloys with x = 5–8 than for those with x = 0–3. This behavior was found to originate from the difference in crystal structures of the martensite phases, i.e., the crystal structures of the martensite phases are 4O and 6M for x = 0–3 and x = 5–8, respectively. Moreover, the geometric compatibility between the parent and martensite phases was found to be the direct cause of the difference in dissipation energy in Ni–Co–Mn–Sn alloys.

ジャーナルJournal of Alloys and Compounds
出版ステータスPublished - 2022 8月 25

ASJC Scopus subject areas

  • 材料力学
  • 機械工学
  • 金属および合金
  • 材料化学


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