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W Zou - One of the best experts on this subject based on the ideXlab platform.
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12 magnetic field induced strain in ni mn ga based non modulated Martensite
Applied Physics Letters, 2013Co-Authors: A Sozinov, N Lanska, A Soroka, W ZouAbstract:Magnetic field-induced strain (MFIS) of 12% is reported in ferromagnetic Ni 46Mn24Ga22Co4 Cu 4 Martensite exhibiting non-modulated (NM) tetragonal crystal structure with lattice parameter ratio c / a > 1 . The strain was measured at ambient temperature in a magnetic field of the order of 1 T. The twinning stress σ T W and the magnetic stress σ M A G were also measured and the condition for a giant MFIS observation σ T W < σ M A G was confirmed. The MFIS was achieved in NM Ni 46Mn24Ga22Co4 Cu 4 Martensite by considerable lowering of the σ T W value as compared to the values for NM Martensites in ternary Ni-Mn-Ga system.
Tetsuya Takeuchi - One of the best experts on this subject based on the ideXlab platform.
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magnetocrystalline anisotropy constant and twinning stress in Martensite phase of ni mn ga
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Nariaki Okamoto, Takashi Fukuda, Tomoyuki Kakeshita, Tetsuya TakeuchiAbstract:Abstract We have examined rearrangement of Martensite variants driven by magnetic field for 10M Martensite in Ni2MnGa and 2M Martensite in Ni2.14Mn0.92Ga0.94 in a wide temperature range below each transformation temperature. The following results are obtained: (i) the twinning plane of the 10M Martensite moves by the application of magnetic field, but that of 2M Martensite does not at any temperature, (ii) in order to explain such difference, we have evaluated the maximum of the magnetic shear stress acting across the twinning plane ( τ mag m ), which is calculated by using the magnetocrystalline anisotropy constant (Ku) measured in this study, and the twinning shear stress (τreq) obtained by compressive test in this study for the 10M and 2M Martensites, and have confirmed whether or not the relation of τ mag m > τ req is satisfied for 10M Martensite and that of τ mag m τ req is satisfied for 2M Martensite. As a result, the above condition is satisfied at any temperatures for 10M and 2M Martensites.
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magnetic field induced martensitic transformation and giant magnetostriction in fe ni co ti and ordered fe3pt shape memory alloys
Materials Transactions Jim, 2000Co-Authors: Tomoyuki Kakeshita, Takashi Fukuda, Tetsuya Takeuchi, Toshio Saburi, Ryuichiro Oshima, Shunsuke Muto, Kohji KishioAbstract:The effect of a magnetic field on martensitic transformations in Fe-Ni-Co-Ti and Fe 3 Pt shape memory alloys has been examined in order to know a magnetic field-induced martensitic transformation and a control of crystallographic domain (variant) by magnetic field. Following results were obtained: (i) Magnetoelastic martensitic transformation (Martensites are induced only while a magnetic field is applied and are transformed back to the parent phase when the magnetic field is removed.) appears in an ausaged Fe-Ni-Ti-Co shape memory alloy. The critical magnetic field for inducing a magnetoelastic martensitic transformation increases with increasing temperature. Volume fraction of Martensite induced depends on the strength of the magnetic field. (ii) Magnetic field controls perfectly the crystallographic domain (variant) in a Martensite state of an ordered Fe 3 Pt, which exhibits a martensitic transformation from a cubic parent phase to a tetragonal Martensite phase. In addition, a giant magnetostriction of about 5 x 10 -3 was realized under a magnetic field of up to 3.2 MA/m, which is nearly three times as large as that of Terfenol-D (Fe 2 Dy x Tb 1-x ).
E Cesari - One of the best experts on this subject based on the ideXlab platform.
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crystal structure of martensitic phases in ni mn ga shape memory alloys
Acta Materialia, 2000Co-Authors: J Pons, V A Chernenko, R Santamarta, E CesariAbstract:Abstract The crystal structures of the different martensitic phases observed in a wide variety of Ni–Mn–Ga alloy compositions have been studied in detail. Similarly to the Ni–Al alloys, the non-modulated Martensite can be well described by the L10 lattice, although it must be “doubled” in order to account for the L21 type of order of the parent phase. Concerning the well known five- and seven-layered Martensites, two approaches taken from the literature are analysed and discussed. The first approach, widely accepted in Ni–Al alloys, describes the structure as long period stacking of {110}P close packed planes (10 M and 14 M structures), while the second one considers lattices modulated by shuffling. The two approaches are shown to be very similar and, in many cases, indistinguishable by the diffraction techniques using photographic recording. However, some physical arguments are given to interpret the five- and seven-layered structures with the second and first approaches, respectively. The structure of the “new” 10-layered Martensite is studied, being described by a (5 5 ) stacking sequence of close-packed planes.
Setsuo Takaki - One of the best experts on this subject based on the ideXlab platform.
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deformation induced martensitic transformation behavior in cold rolled and cold drawn type 316 stainless steels
Acta Materialia, 2010Co-Authors: Nobuo Nakada, Yoshikazu Matsuoka, Toshihiro Tsuchiyama, Setsuo TakakiAbstract:Abstract We investigate deformation-induced martensitic transformation behavior in cold-rolled and cold-drawn specimens of type 316 stainless steel. Deformation-induced Martensite preferentially nucleates at the twin boundary between the austenite matrix and a deformation twin. In the cold-rolled specimen, Martensite formed at the twin boundary has a Kurdjumov–Sachs (K–S) relationship with both the austenite matrix and the deformation twin (“double K–S relationship”). In the cold-drawn specimen, two kinds of deformation twins with different twin planes are typically formed, and therefore deformation-induced Martensites are formed where the deformation twin boundaries intersect: Martensite thus has an imperfect “triple K–S relationship” with the austenite matrix and the two deformation twins. The complicated crystallographic orientation relationship between austenite and Martensite grains strongly restricts the formation of some variants of deformation-induced Martensites. Because of the difference in number of nucleation sites in the cold-drawn and cold-rolled specimens, martensitic transformation is more enhanced in the former than in the latter.
A Sozinov - One of the best experts on this subject based on the ideXlab platform.
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12 magnetic field induced strain in ni mn ga based non modulated Martensite
Applied Physics Letters, 2013Co-Authors: A Sozinov, N Lanska, A Soroka, W ZouAbstract:Magnetic field-induced strain (MFIS) of 12% is reported in ferromagnetic Ni 46Mn24Ga22Co4 Cu 4 Martensite exhibiting non-modulated (NM) tetragonal crystal structure with lattice parameter ratio c / a > 1 . The strain was measured at ambient temperature in a magnetic field of the order of 1 T. The twinning stress σ T W and the magnetic stress σ M A G were also measured and the condition for a giant MFIS observation σ T W < σ M A G was confirmed. The MFIS was achieved in NM Ni 46Mn24Ga22Co4 Cu 4 Martensite by considerable lowering of the σ T W value as compared to the values for NM Martensites in ternary Ni-Mn-Ga system.
