Neutron Diffraction Study of the Martensitic Transformation and Chemical Order in Heusler Alloy Ni1.91Mn1.29Ga0.8

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • Western Michigan University
  • Oak Ridge National Laboratory
  • Russian Academy of Sciences

Abstract

Heusler alloys of Ni-Mn-Ga compositions demonstrate ferromagnetic shape memory effect in the martensitic state. The transformation temperature and the chemical order depend strongly on the composition. In the current work, the structure and chemical order of the martensitic phase of Ni1.91Mn1.29Ga0.8 were studied using neutron diffraction; the diffraction pattern was refined using the FullProf software. It was determined that the structural transition occurs around 330 K. At room temperature, 300 K, which is below the martensite transformation temperature, all the Bragg reflections can be described by a monoclinic lattice with a symmetry of space group P 1 2/m 1 and lattice constants of a = 4.23047(7) [Å], b = 5.58333(6) [Å], c = 21.0179(2) [Å], beta = 90.328(1). The chemical order is of critical importance in these alloys, and it was previously studied at 363 K. Analysis of the neutron diffraction in the monoclinic phase shows that the chemical order is maintained during the martensitic transformation.

Details

Original languageEnglish
Pages (from-to)853-857
Number of pages5
JournalMaterials Today: Proceedings
Volume2
Issue numberSupplement 3
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed
EventInternational Conference on Martensitic Transformations - Bilbao, Spain
Duration: 7 Jul 201411 Jul 2014

    Research areas

  • Chemical Order, Ni-Mn-Ga alloy, Magnetic Shape Memory, Neutron Diffraction, Rietveld Method, Structure Refinement

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