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Title: In-situ neutron diffraction study of martensitic variant redistribution in polycrystalline Ni-Mn-Ga alloy under cyclic thermo-mechanical treatment

The influences of uniaxial compressive stress on martensitic transformation were studied on a polycrystalline Ni-Mn-Ga bulk alloy prepared by directional solidification. Based upon the integrated in-situ neutron diffraction measurements, direct experimental evidence was obtained on the variant redistribution of seven-layered modulated (7M) martensite, triggered by external uniaxial compression during martensitic transformation. Large anisotropic lattice strain, induced by the cyclic thermo-mechanical treatment, has led to the microstructure modification by forming martensitic variants with a strong 〈0 1 0〉{sub 7M} preferential orientation along the loading axis. As a result, the saturation of magnetization became easier to be reached.
Authors:
; ; ;  [1] ; ;  [2] ;  [3] ;  [4]
  1. Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China)
  2. Laboratoire d'Étude des Microstructures et de Mécanique des Matériaux (LEM3), CNRS UMR 7239, Université de Lorraine, 57045 Metz (France)
  3. (DAMAS), Université de Lorraine, 57045 Metz (France)
  4. German Engineering Materials Science Centre (GEMS), Helmholtz-Zentrum Geesthacht (HZG) Outstation at FRM II, D-85748, Garching (Germany)
Publication Date:
OSTI Identifier:
22311074
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; COMPRESSION; GALLIUM COMPOUNDS; MAGNETIZATION; MANGANESE ALLOYS; MARTENSITIC STEELS; MICROSTRUCTURE; MODIFICATIONS; NEUTRON DIFFRACTION; NICKEL ALLOYS; POLYCRYSTALS; SATURATION; SOLIDIFICATION; STRAINS; STRESSES; THERMOMECHANICAL TREATMENTS