Functional stability of a ferromagnetic polycrystalline Ni2MnGa high temperature shape memory alloy

M.A. Azeem, N.G. Jones, S.L. Raghunathan, V.A. Vorontsov, D. Dye

Research output: Contribution to journalArticle

1 Citation (Scopus)
9 Downloads (Pure)

Abstract

Electrocaloric Ni2MnGa is of interest for solid state refrigeration applications, as well as a high temperature thermal shape memory alloy. Here, polycrystalline Ni54Mn25Ga21 is examined using in situ synchrotron X-ray diffraction. The initial martensite (Mf) and austenite (Af) finish temperatures were found to be 232 ° C and 298 ° C respectively. Mf was observed to decline by 8 ° C/cycle and Af increased by 1 ° C/cycle. Both below and surprisingly, above the Curie temperature, the application of an e.m.f. was found to affect the lattice parameters measured. A change in the thermal expansion of the two phases was found around the Curie temperature.

Original languageEnglish
Pages (from-to)274-277
Number of pages4
JournalScripta Materialia
Volume130
Early online date29 Dec 2016
DOIs
Publication statusPublished - 15 Mar 2017

Fingerprint

heat resistant alloys
shape memory alloys
Curie temperature
Shape memory effect
cycles
Refrigeration
austenite
martensite
Synchrotrons
Martensite
Austenite
Lattice constants
Thermal expansion
thermal expansion
lattice parameters
synchrotrons
solid state
X ray diffraction
Temperature
Electric potential

Keywords

  • ferromagnetic shape memory alloy
  • intermetallic compounds
  • synchrotron radiation
  • thermal expansion

Cite this

Azeem, M.A. ; Jones, N.G. ; Raghunathan, S.L. ; Vorontsov, V.A. ; Dye, D. / Functional stability of a ferromagnetic polycrystalline Ni2MnGa high temperature shape memory alloy. In: Scripta Materialia. 2017 ; Vol. 130. pp. 274-277.
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Functional stability of a ferromagnetic polycrystalline Ni2MnGa high temperature shape memory alloy. / Azeem, M.A.; Jones, N.G.; Raghunathan, S.L.; Vorontsov, V.A.; Dye, D.

In: Scripta Materialia, Vol. 130, 15.03.2017, p. 274-277.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Functional stability of a ferromagnetic polycrystalline Ni2MnGa high temperature shape memory alloy

AU - Azeem, M.A.

AU - Jones, N.G.

AU - Raghunathan, S.L.

AU - Vorontsov, V.A.

AU - Dye, D.

PY - 2017/3/15

Y1 - 2017/3/15

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AB - Electrocaloric Ni2MnGa is of interest for solid state refrigeration applications, as well as a high temperature thermal shape memory alloy. Here, polycrystalline Ni54Mn25Ga21 is examined using in situ synchrotron X-ray diffraction. The initial martensite (Mf) and austenite (Af) finish temperatures were found to be 232 ° C and 298 ° C respectively. Mf was observed to decline by 8 ° C/cycle and Af increased by 1 ° C/cycle. Both below and surprisingly, above the Curie temperature, the application of an e.m.f. was found to affect the lattice parameters measured. A change in the thermal expansion of the two phases was found around the Curie temperature.

KW - ferromagnetic shape memory alloy

KW - intermetallic compounds

KW - synchrotron radiation

KW - thermal expansion

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