Specific heat and entropy change during martensitic transformation in Ni50Mn50-xGax ferromagnetic shape memory alloys

Xiao Xu; Takeshi Kanomata; Ryosuke Kainuma

doi:10.1016/j.actamat.2014.06.036

Specific heat and entropy change during martensitic transformation in Ni₅₀Mn_50-xGa_x ferromagnetic shape memory alloys

Xiao Xu, Takeshi Kanomata, Ryosuke Kainuma

ENG - Metallurgy

Research output: Contribution to journal › Article › peer-review

9 Citations (Scopus)

Abstract

Specific heat was systematically measured for Ni₅₀Mn _50-xGa_x ferromagnetic shape memory alloys near the martensitic transformation temperatures. Martensitic and intermediate transformations and magnetic transitions in the parent and martensite phases were directly observed via specific heat measurements. Entropy change during the intermediate transformation was successfully estimated by direct measurement. Entropy change during the martensitic transformation was also analyzed; it generally decreases with decreasing Ga concentration. Anomalous behavior of the entropy change during martensitic transformation was observed near the magnetic transitions, and was found to attributable to the magnetic contribution by a qualitative examination based on the results of specific heat measurements.

Original language	English
Pages (from-to)	159-167
Number of pages	9
Journal	Acta Materialia
Volume	79
DOIs	https://doi.org/10.1016/j.actamat.2014.06.036
Publication status	Published - 2014 Oct 15

Keywords

Entropy change
Ferromagnetic shape memory alloy
Magnetostructural transformations
Ni-Mn-Ga
Specific heat

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Polymers and Plastics
Metals and Alloys

Access to Document

10.1016/j.actamat.2014.06.036

Cite this

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title = "Specific heat and entropy change during martensitic transformation in Ni50Mn50-xGax ferromagnetic shape memory alloys",

abstract = "Specific heat was systematically measured for Ni50Mn 50-xGax ferromagnetic shape memory alloys near the martensitic transformation temperatures. Martensitic and intermediate transformations and magnetic transitions in the parent and martensite phases were directly observed via specific heat measurements. Entropy change during the intermediate transformation was successfully estimated by direct measurement. Entropy change during the martensitic transformation was also analyzed; it generally decreases with decreasing Ga concentration. Anomalous behavior of the entropy change during martensitic transformation was observed near the magnetic transitions, and was found to attributable to the magnetic contribution by a qualitative examination based on the results of specific heat measurements.",

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T1 - Specific heat and entropy change during martensitic transformation in Ni50Mn50-xGax ferromagnetic shape memory alloys

AU - Xu, Xiao

AU - Kanomata, Takeshi

AU - Kainuma, Ryosuke

PY - 2014/10/15

Y1 - 2014/10/15

N2 - Specific heat was systematically measured for Ni50Mn 50-xGax ferromagnetic shape memory alloys near the martensitic transformation temperatures. Martensitic and intermediate transformations and magnetic transitions in the parent and martensite phases were directly observed via specific heat measurements. Entropy change during the intermediate transformation was successfully estimated by direct measurement. Entropy change during the martensitic transformation was also analyzed; it generally decreases with decreasing Ga concentration. Anomalous behavior of the entropy change during martensitic transformation was observed near the magnetic transitions, and was found to attributable to the magnetic contribution by a qualitative examination based on the results of specific heat measurements.

AB - Specific heat was systematically measured for Ni50Mn 50-xGax ferromagnetic shape memory alloys near the martensitic transformation temperatures. Martensitic and intermediate transformations and magnetic transitions in the parent and martensite phases were directly observed via specific heat measurements. Entropy change during the intermediate transformation was successfully estimated by direct measurement. Entropy change during the martensitic transformation was also analyzed; it generally decreases with decreasing Ga concentration. Anomalous behavior of the entropy change during martensitic transformation was observed near the magnetic transitions, and was found to attributable to the magnetic contribution by a qualitative examination based on the results of specific heat measurements.

KW - Entropy change

KW - Ferromagnetic shape memory alloy

KW - Magnetostructural transformations

KW - Ni-Mn-Ga

KW - Specific heat

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