Atomic order and martensitic transformation entropy change in Ni–Co–Mn–In metamagnetic shape memory alloys

Pérez-Sierra, A.M.; Bruno, Nickolaus M.; Pons, J.; Cesari, E.; Караман, И.

doi:10.1016/j.scriptamat.2015.07.047

Cited by 26 publications

(6 citation statements)

References 30 publications

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“…In these materials, magnetic field drives martensitic transformations and, therefore, the latent heat of the structural transition generates the giant inverse magnetocaloric effect (MCE)1213141516171819. The NiCoMnIn MMSMAs studied here have been reported to exhibit temperature changes as large as 6 K across martensite to austenite magnetic-field-induced transformations7 (MFITs), however, large magnetic fields, i.e.…”

mentioning

confidence: 92%

Reversible Martensitic Transformation under Low Magnetic Fields in Magnetic Shape Memory Alloys

Bruno

Wang

Караман

et al. 2017

Sci Rep

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Magnetic field-induced, reversible martensitic transformations in NiCoMnIn meta-magnetic shape memory alloys were studied under constant and varying mechanical loads to understand the role of coupled magneto-mechanical loading on the transformation characteristics and the magnetic field levels required for reversible phase transformations. The samples with two distinct microstructures were tested along the [001] austenite crystallographic direction using a custom designed magneto-thermo-mechanical characterization device while carefully controlling their thermodynamic states through isothermal constant stress and stress-varying magnetic field ramping. Measurements revealed that these meta-magnetic shape memory alloys were capable of generating entropy changes of 14 J kg−1 K−1 or 22 J kg −1 K−1, and corresponding magnetocaloric cooling with reversible shape changes as high as 5.6% under only 1.3 T, or 3 T applied magnetic fields, respectively. Thus, we demonstrate that this alloy is suitable as an active component in near room temperature devices, such as magnetocaloric regenerators, and that the field levels generated by permanent magnets can be sufficient to completely transform the alloy between its martensitic and austenitic states if the loading sequence developed, herein, is employed.

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mentioning

confidence: 92%

Reversible Martensitic Transformation under Low Magnetic Fields in Magnetic Shape Memory Alloys

Bruno

Wang

Караман

et al. 2017

Sci Rep

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“…It has been shown that the increase of S  is mostly due to the decreasing magnetic order of austenite as M T approaches CA T [10]. The calculated magnetic contributions are close to the experimental values, or even exceed them when T CA − T M < 120 K. If the opposite inequality is fulfilled, the majority of the total experimental values noticeably exceed the calculated magnetic contribution.…”

Section: Evaluation Of Magnetic and Non-magnetic Contributions To ∆S mentioning

confidence: 51%

“…At the same time, as the direct transformation is exothermic, the inequality S M < S A takes place, and in accordance with the notation accepted above, ∆S =|S M − S A |= S A − S M > 0 . It has been shown that the increase of ∆S is mostly due to the decreasing magnetic order of austenite as T M approaches T CA [10].…”

Section: Evaluation Of Magnetic and Non-magnetic Contributions To ∆S mentioning

confidence: 99%

Entropy Change Caused by Martensitic Transformations of Ferromagnetic Shape Memory Alloys

L’vov

Cesari

Kosogor

et al. 2017

Metals

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Abstract:In this paper, our most recent findings on the influence of magnetic order on the main transformational caloric and elastic properties of shape memory alloys (SMAs) are reviewed. It is argued that ferromagnetic order has a strong influence on the temperature interval of martensitic transformation (MT), the characteristics of stress-induced MT, and the shear elastic modulus of SMA. The problem of separation of the magnetic contributions to the entropy change ∆S and heat Q exchanged in the course of martensitic transformation (MT) of SMA is considered in general terms, and theoretical formulas enabling the solution of the problem are presented. As an example, the ∆S and Q values, which were experimentally determined for Ni-Mn-Ga and Ni-Fe-Ga alloys with different Curie temperatures T C and MT temperatures T M , are theoretically analyzed. It is shown that for Ni-Mn-Ga martensites with T M < T C , the ratio of elastic and magnetic contributions to the entropy change may be greater or smaller than unity, depending on the temperature difference T C -T M .

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“…The degree of long-range L2 1 atomic order significantly lowers the transformation entropy change through large shifts in the transformation temperatures in relation to the change in magnetization of the austenite phase [165,166,167,168]. While L2 1 atomic order refers to the fraction of atoms located in the correct sublattice of L2 1 structure, studies show it can be varied by thermal treatment.…”

Section: Microstructural Effects On Propertiesmentioning

confidence: 99%

Ferromagnetic Shape Memory Heusler Materials: Synthesis, Microstructure Characterization and Magnetostructural Properties

et al. 2018

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An overview of the processing, characterization and magnetostructural properties of ferromagnetic NiMnX (X = group IIIA–VA elements) Heusler alloys is presented. This type of alloy is multiferroic—exhibits more than one ferroic property—and is hence multifunctional. Examples of how different synthesis procedures influence the magnetostructural characteristics of these alloys are shown. Significant microstructural factors, such as the crystal structure, atomic ordering, volume of unit cell, grain size and others, which have a bearing on the properties, have been reviewed. An overriding factor is the composition which, through its tuning, affects the martensitic and magnetic transitions, the transformation temperatures, microstructures and, consequently, the magnetostructural effects.

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Atomic order and martensitic transformation entropy change in Ni–Co–Mn–In metamagnetic shape memory alloys

Cited by 26 publications

References 30 publications

Reversible Martensitic Transformation under Low Magnetic Fields in Magnetic Shape Memory Alloys

Reversible Martensitic Transformation under Low Magnetic Fields in Magnetic Shape Memory Alloys

Entropy Change Caused by Martensitic Transformations of Ferromagnetic Shape Memory Alloys

Ferromagnetic Shape Memory Heusler Materials: Synthesis, Microstructure Characterization and Magnetostructural Properties

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