Metals (Aug 2013)

The Thermal Transformation Arrest Phenomenon in NiCoMnAl Heusler Alloys

  • Rie Y. Umetsu,
  • Takeshi Kanomata,
  • Kengo Oka,
  • Takumi Kihara,
  • Wataru Ito,
  • Masashi Tokunaga,
  • Xiao Xu,
  • Ryosuke Kainuma

DOI
https://doi.org/10.3390/met3030298
Journal volume & issue
Vol. 3, no. 3
pp. 298 – 311

Abstract

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In this report, we present findings of systematic research on NiCoMnAl alloys, with the purpose of acquiring a higher thermal transformation arrest temperature (TA). By systematic research, TA in the NiCoMnAl alloy systems was raised up to 190 K, compared to the highest TA of 130 K in NiCoMnIn. For a selected alloy of Ni40Co10Mn33Al17, magnetization measurements were performed under a pulsed high magnetic field, and the critical magnetic field-temperature phase diagram was determined. The magnetic phase diagram for Ni50-xCoxMn50-yAly was also established. Moreover, from the discussion that the formerly called “kinetic arrest phenomenon” has both thermodynamic and kinetic factors, we suggest a terminology change to the “thermal transformation arrest phenomenon”.

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