Temperature dependence of elastic properties in austenite and martensite of Ni-Mn-Ga epitaxial films

Heczko, Oleg; Seiner, Hanuš; Stoklasová, Pavla; Sedlák, Petr; Sermeus, Jan; Glorieux, Christ; Backen, Anja; Fähler, Sebastian; Landa, Michal

doi:10.1016/j.actamat.2017.12.011

Cited by 37 publications

(11 citation statements)

References 52 publications

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“…Such an A → NM transformation will be also preceded by a softening of the C′ elastic moduli above the martensitic transformation temperature, although the transformation is driven solely by the Jahn–Teller effect and its mechanism completely differs from the mechanism of the A → 6M transformation. This behavior has recently been observed experimentally in thin films 41 and polycrystalline bulk 42 .…”

Section: Discussionsupporting

confidence: 69%

Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound

Zelený

Straka

Sozinov

et al. 2018

Sci Rep

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In order to explain the formation of low-temperature phases in stoichiometric Ni2MnGa magnetic shape memory alloy, we investigate the phase transformation paths from cubic austenite with Heusler structure to low-symmetry martensitic structures. We used ab initio calculations combined with the generalized solid state nudged elastic band method to determine the minimum energy path and corresponding changes in crystal lattice. The four-, five-, and seven-layered modulated phases of martensite (4O, 10M, and 14M) are built as the relaxed nanotwinned non-modulated (NM) phase. Despite having a total energy larger than the other martensitic phases, the 10M phase will spontaneously form at 0 K, because there is no energy barrier on the path and the energy decreases with a large negative slope. Moreover, a similar negative slope in the beginning of path is found also for the transformation to the 6M premartensite, which appears as a local minimum on the path leading further to 10M martensite. Transformation paths to other structures exhibit more or less significant barriers in the beginning hindering such a transformation from austenite. These findings correspond to experiment and demonstrates that the kinetics of the transformation is decisive for the selection of the particular low-symmetry structure.

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Section: Discussionsupporting

confidence: 69%

Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound

Zelený

Straka

Sozinov

et al. 2018

Sci Rep

Self Cite

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“…Among recent applications of the technique, the characterization of nanocrystalline diamond coatings [99], and the exploitation of the optical character of the technique to perform measurements at different temperatures [100], and in situ measurements [101]. As previously mentioned, the possibility of tuning the periodicity λ ∥ allows to choose the depth which is probed.…”

Section: Transient Grating Spectroscopymentioning

confidence: 99%

Ultrasonic and Spectroscopic Techniques for the Measurement of the Elastic Properties of Nanoscale Materials

Beghi¹

2021

Nanomechanics - Theory and Application

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Materials at the nanoscale often have properties which differ from those they have in the bulk form. These properties significantly depend on the production process, and their measurement is not trivial. The elastic properties characterize the ability of materials to deform in a reversible way; they are of interest by themselves, and as indicators of the type of nanostructure. As for larger scale samples, the measurement of the elastic properties is more straightforward, and generally more precise, when it is performed by a deformation process which involves exclusively reversible strains. Vibrational and ultrasonic processes fulfill this requirement. Several measurement techniques have been developed, based on these processes. Some of them are suitable for an extension towards nanometric scales. Until truly supramolecular scales are reached, the elastic continuum paradigm remains appropriate for the description and the analysis of ultrasonic regimes. Some techniques are based on the oscillations of purpose-built testing structures, mechanically actuated. Other techniques are based on optical excitation and/or detection of ultrasonic waves, and operate either in the time domain or in the frequency domain. A comparative overview is given of these various techniques.

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“…It is due to the fact that the simple shear deformation or Bain distortion which transforms austenite into individual martensitic variants, operates along the main orthogonal axes of austenite (for orthorhombic, monoclinic, triclinic crystal structures) or the martensite unite lattice is rotated 45 degrees about the [001] direction with respect to austenite (tetragonal case). However, using the parent-based coordinates and an approximate 3 unite cell does not define the symmetry and atom positions of the entire crystal structure [Straka et al, 2012;Seiner et al, 2014;Zhou et al, 2017;Heczko et al, 2018]. Especially the small atomic displacement associated with lattice modulation is not included.…”

Section: Introductionmentioning

confidence: 99%

Hierarchical twin microstructure in modulated 10M Ni–Mn-Ga single crystals. An analysis including shuffling of atomic layers

Chulist

Nalepka

Sozinov

2020

International Journal of Plasticity

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Temperature dependence of elastic properties in austenite and martensite of Ni-Mn-Ga epitaxial films

Cited by 37 publications

References 52 publications

Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound

Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound

Ultrasonic and Spectroscopic Techniques for the Measurement of the Elastic Properties of Nanoscale Materials

Hierarchical twin microstructure in modulated 10M Ni–Mn-Ga single crystals. An analysis including shuffling of atomic layers

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