Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu

Barabash, Rozaliya; Barabash, Oleg M; Popov, Dmitry; Shen, Guoyin; Park, Changyong; Yang, Wenge

doi:10.1016/j.actamat.2015.01.010

Cited by 13 publications

(8 citation statements)

References 45 publications

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“…Furthermore, by going through systematic indexation, orientations of crystals can be determined, which in turn can be used to find orientation relations between coexisting parent and product phases. Relative orientations of single crystals can be determined from one Laue diffraction pattern with an angular precision down to~0.02 • , which makes Laue diffraction a powerful tool for characterizing twining [21]. By application of the polychromatic beam diffraction, one can overcome a major challenge to recognize domain structures formed after phase transitions: the newly formed domains typically have pseudo symmetrical translational lattices with very low mismatch with respect to the lattice of parental phase [22].…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of Pressure-Induced Phase Transitions by Real-Time Laue Diffraction

2019

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Synchrotron X-ray radiation Laue diffraction is a widely used diagnostic technique for characterizing the microstructure of materials. An exciting feature of this technique is that comparable numbers of reflections can be measured several orders of magnitude faster than using monochromatic methods. This makes polychromatic beam diffraction a powerful tool for time-resolved microstructural studies, critical for understanding pressure-induced phase transition mechanisms, by in situ and in operando measurements. The current status of this technique, including experimental routines and data analysis, is presented along with some case studies. The new experimental setup at the High-Pressure Collaborative Access Team (HPCAT) facility at the Advanced Photon Source, specifically dedicated for in situ and in operando microstructural studies by Laue diffraction under high pressure, is presented.

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Section: Discussionmentioning

confidence: 99%

Mechanisms of Pressure-Induced Phase Transitions by Real-Time Laue Diffraction

2019

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“…there is an abrupt, almost by 50%, increase of the phonons' free path length, thus causing the observed sudden change κ ph (T ) near the MSPT. Local distortions of the crystal lattice and nanosized twin boundaries, concentration of which rises upon a transition to the martensitic phase [16,27], can be considered as a mechanism leading to a sudden change of l ph .…”

Section: Resultsmentioning

confidence: 99%

Heat capacity, thermal conductivity and magnetocaloric effect in Heusler alloy Ni-=SUB=-47-=/SUB=-Mn-=SUB=-40-=/SUB=-Sn-=SUB=-13-=/SUB=-

Gamzatov

Batdalov

et al. 2022

Physics of the Solid State

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The results of a study of heat capacity, thermal conductivity and magnetocaloric effect of the polycrystalline Ni47Mn40Sn13 alloy depending on temperature (T=80-350 K) and magnetic field (0-8 T) are given. A considerable difference between the values of a sudden change in heat capacity Delta CP in the heating and cooling mode was found near the magnetostructural martensite--austenite phase transition (MSPT), which is related to influence of latent heat of phase transition. Thermal conductivity in the range of T=80-300 K rises with temperature (dkappa/dT>0) and increases in more than three times. Electronic thermal conductivity in the martensitic phase (T=150 K) is 37% of the total value. An anomalous rise of thermal conductivity Deltakappa=kappa(aust)-kappa(mart)=4.2 Wm K was found in the region of MSPT. The contributions of electrons and phonons to the observed sudden change are 63 and 37% respectively and are conditioned both by a rise of mobility of conduction electrons under a martensite--austenite transition and by an increase of phonons' free path length. The magnetocaloric effect in cyclic magnetic fields with the amplitude of 1.8 T was studied. A dependence of reverse effect value on temperature scanning rate was established. The direct measurements of Delta T in the cyclic magnetic field of 1.2 T show a twofold decrease of the effect amplitude near TC at an increase of cyclic magnetic field frequency from 1 to 30 Hz. Most likely, this is related to magnetic and microstructural heterogeneities which act as an additional thermal dissipation channel. Keywords: Heusler alloys, heat capacity, thermal conductivity, magnetocaloric effect, cyclic magnetic fields.

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“…Fine laminates of these types of twins were found in the vicinity of the highly mobile interfaces also by Straka et al [11], Heczko et al [33] and Chulist et al [41]; as a result, the mobile interface is then a macro-twin interfaces between these laminates. The micro-morphology of such interfaces was shown to have a multi-scale hierarchical character by Barabash et al [42] for the case of 10 M martensite of NiMnGaFeCu. Typically, this complex structure is not discussed in the theoretical models of motion, including those of the mobility of the twins by Faran and Shilo [25][26][27][28][29] as well as continuum mechanics or phase field models of MIR [43,44].…”

Section: Finer Structure Of the Mobile Interfacementioning

confidence: 99%

Highly mobile interfaces in shape memory alloys

Seiner

2015

MATEC Web of Conferences

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Abstract. Macro-twin interfaces in single crystals of 10 M modulated Ni-Mn-Ga martensite have recently attracted a lot of attention due to the extraordinarily low twinning stress required to set them into motion; depending on the particular twinning mode, this stress can range between 0.05 and 1 MPa, and can be either strongly temperature dependent, or nearly temperature independent. The understanding to these effects is still not satisfactory, mainly due to the high complexity of these interfaces at the micro-scale (higher-order lamination) as well as at the atomistic scale (modulations of martensite). This paper brings a brief review of the recent experimental and theoretical achievements related to these highly mobile interfaces. The uniqueness of the behavior of 10 M martensite is shown by its comparison with other shape memory alloys with relatively low twinning stresses; then, this behavior is discussed in terms of its temperature dependence, strain rate dependence and the effect of the micromorphology of the interfaces.

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Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu

Cited by 13 publications

References 45 publications

Mechanisms of Pressure-Induced Phase Transitions by Real-Time Laue Diffraction

Mechanisms of Pressure-Induced Phase Transitions by Real-Time Laue Diffraction

Heat capacity, thermal conductivity and magnetocaloric effect in Heusler alloy Ni-=SUB=-47-=/SUB=-Mn-=SUB=-40-=/SUB=-Sn-=SUB=-13-=/SUB=-

Highly mobile interfaces in shape memory alloys

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