Journal ArticleDOI
Giant magnetic-field-induced strain in NiMnGa seven-layered martensitic phase
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TLDR
In this paper, a magnetic-field-induced strain of about 9.5% was observed at ambient temperature in a magnetic field of less than 1 T in NiMnGa orthorhombic seven-layered martensitic phase.Abstract:
Giant magnetic-field-induced strain of about 9.5% was observed at ambient temperature in a magnetic field of less than 1 T in NiMnGa orthorhombic seven-layered martensitic phase. The strain proved to be caused by magnetic-field-controlled twin boundary motion. According to an analysis of x-ray diffraction data, the crystal structure of this phase is nearly orthorhombic, having lattice parameters a=0.619 nm, b=0.580 nm, and c=0.553 nm (in cubic parent phase coordinates) at ambient temperature. Seven-layer shuffling-type modulation along the (110)[110]p system was recorded. The results of mechanical tests and magnetic anisotropy property measurements are also reported.read more
Citations
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Acoustic-assist effect on magnetic threshold field and twinning-yield stress of Ni-Mn-Ga single crystals
TL;DR: In this article, the authors systematically studied the threshold field and the twinning-yield stress of Ni-Mn-Ga single crystals with and without acoustic assist, and showed that the effectiveness of the acoustic assistance in enhancing twin-boundary motion increases with increasing acoustic drive frequency up to a limiting frequency of 2-5 kHz.
Journal ArticleDOI
First-principles study of the lattice instabilities in Mn2NiX (X = Al, Ga, In, Sn) magnetic shape memory alloys
TL;DR: The results indicate that the phonon anomalies are related to the occurrence of possible pre-martensitic phases which can be quite complex.
Journal ArticleDOI
Effects of Surface Modifications on the Fatigue Life of Unconstrained Ni-Mn-Ga Single Crystals in a Rotating Magnetic Field
TL;DR: In this paper, a rotary fatigue testing instrument for Ni-Mn-Ga single crystal samples treated with various surface modifications was investigated in the presence of electropolishing and micro-peening.
Journal ArticleDOI
Magneto-microstructural coupling during stress-induced phase transformation in Co49Ni21Ga30 ferromagnetic shape memory alloy single crystals
TL;DR: In this paper, the authors reported on direct magneto-microstructural observations made during the stress-induced martensitic transformation in Co49Ni21Ga30 alloy single crystals with optical, scanning electron, and magnetic force microscopy (MFM).
Journal ArticleDOI
Direct evidence for stress-induced transformation between coexisting multiple martensites in a Ni–Mn–Ga multifunctional alloy
Lingling Huang,Lingling Huang,D.Y. Cong,Z. L. Wang,Zhihua Nie,Y. H. Dong,Yong Zhang,Yang Ren,Yandong Wang +8 more
TL;DR: In this article, the structural response of coexisting multiple martensites to stress field in a Ni-Mn-Ga multifunctional alloy was investigated by the in situ high-energy x-ray diffraction technique.
References
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Journal ArticleDOI
Large magnetic‐field‐induced strains in Ni2MnGa single crystals
TL;DR: In this paper, the superelastic motion of twin boundaries in the martensitic phase of Ni2MnGa with magnetic fields of 8 kOe applied at 265 K was found to be associated with the staining.
Journal ArticleDOI
6% magnetic-field-induced strain by twin-boundary motion in ferromagnetic Ni–Mn–Ga
TL;DR: In this paper, a simple model accounts quantitatively for the dependence of strain on magnetic field and external stress using as input parameters only measured quantities, and the strain versus field curves exhibit appreciable hysteresis associated with the motion of the twin boundaries.
Journal ArticleDOI
Magnetostriction of martensite
Richard D. James,Manfred Wuttig +1 more
TL;DR: In this article, a general strategy for inducing magnetostriction in ferromagnetic martensitic materials is described, and an analysis of domain redistribution caused by a magnetic field is given.
Journal ArticleDOI
Model for strain and magnetization in magnetic shape-memory alloys
TL;DR: In this paper, a simple phenomenological model for the magnetization process and field-induced strain by twin-boundary and phaseboundary motion is proposed for both the strong and weak anisotropy cases.
Journal ArticleDOI
Crystal structure of martensitic phases in Ni–Mn–Ga shape memory alloys
TL;DR: The crystal structures of the different martensitic phases observed in a wide variety of Ni-Mn-Ga alloy compositions have been studied in detail as discussed by the authors, and two approaches taken from the literature are analysed and discussed.