Temperature Dependence of the Magnetization of the Ni52Mn24Ga24 Alloy in Various Structural States

Musabirov, I. I.; Sharipov, I. Z.; Mulyukov, R. R.

doi:10.1007/s11182-015-0561-2

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…As a rule, the SM effect is associated with thermoelastic MT, which have low values of critical deformations and high coherence of phases, which contributes to reversibility of MT upon heating. To date, thermoelastic MT was studied for industrially important allows: Ti-Ni-Cu systems [4], Ti-Ni-Hf [5], Ni-Mn-Ti alloys [6], Ni-Mn-Ga systems [7,8] to name a few. Using the ideas about the role of DNC and controlling wave process in calculating the morphological features of MT in alloys with SM effect [9,10], including specific twinning variants [11], leads to good agreement with the experiment.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulation of the effect of dislocations on the martensitic transformations in a two-dimensional model

Кащенко¹,

Baimova²,

Babicheva³

et al. 2017

LoM

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Investigation of the thermoelastic martensitic transformation is of high interest nowadays because of the numerous applications of the materials with such structural peculiarities. Thermodynamics, kinetics, structure, morphology of martensitic transformation still remain unclear in many respects. From this point of view, the effective way to study various properties of metallic crystals on atomistic level is molecular dynamics simulation, for which good qualitative agreement with the experiment can be achieved even with simple Morse or Lennard-Jones interatomic potentials. In this paper, the effect of dislocations on the direct and reverse martensitic transformation is studied by molecular dynamics simulation in a two-dimensional model of the ordered alloy with the AB stoichiometry. The three dimensional analog to this structure is B2 superstructure based on bcc lattice, which is characteristic for intermetallic NiTi alloy. It is found, that the dislocations can be considered as the nucleation centers for martensite phase, increasing the temperature of the direct martensitic transformation in comparison with the homogeneous martensitic transformation. The martensite domains found in the structure after transformation and the reverse martensitic transformation takes place in the presence of the domain boundaries, meaning that the austenite nucleates heterogeneously. At the reverse transformation, splitting of perfect dislocations into partials dislocations took place. Thus, it was established in the present study that, on the one hand, dislocations affect the direct martensitic transformation as the nucleation centers, and from the other hand, reverse martensitic transformation changes the dislocation structure of the modeled alloy.

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Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulation of the effect of dislocations on the martensitic transformations in a two-dimensional model

Кащенко¹,

Baimova²,

Babicheva³

et al. 2017

LoM

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“…In the course of thermocycling the multiple forward and reverse transformations caused and numerous alloys show the phase hardening which in its turn leads to the structure and properties degradation. One of the possible ways to change and increase functional and operational properties of such alloys is the severe plastic deformation which leads to the grain refinement to the nanoscale [3]. The grain refinement cause the decrease of the maximal size of the phase domains and subsequently to the decrease of the deformation of the crystal structure by the inconsistency of the shape and size of the primitive cells of austenite and martensite phases.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional model of the ordered alloy for the investigation of martensitic transformations

Babicheva¹,

Baimova²,

Dmitriev³

et al. 2015

LoM

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Two-dimensional model of diatomic crystal is proposed in the present work for the investigation of martensitic transformation under thermomechanical treatment, i.e. the proposed modell allows to simulate temperature effect as well as external loading, like tension, plastic deformation, ets. The model, based on the Morse potential, which are used for the simulation of the diatomic crystal of NiTi type, which is well known as an alloy with the martensitic transformation. This model allows one to define the main characteristics of different phases as the function of one of the potential parameter at 0 K. Potential parameters for the realization of forward and reverse martensitic transformation at finite temperatures are found by the careful checking of all the values. The appearance of one preferable martensite phase is shown despite there are two possible martensite phases. The appearance of the domain boundaries is shown for the martensite phase because of the realization of two opposite direction of martensite growth. The starting and finishing temperatures of the martensitic transformation are obtained. The effect of external stresses on the course of the martensitic transformation is investigated. The potential present in this work can be perspectively used for the investigation of such processes as phase hardening in diatomic crystals.

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“…Условия протекания деформации приконтактных объемов, такие как степень и скорость деформации, время сварки, структурные превращения при деформации и нагреве влияют на качество и эксплуатационные свойства сварного соединения [6 -8]. При этом характер микроструктуры также оказывает значительное влияние на свойства материала [9,10]. В частности, высоколегированные сплавы на никелевой основе, является гетерофазным, вследствие чего в исходном крупнозернистом состоянии имеют низкую технологическую пластичность.…”

Section: Introductionunclassified

The role of shear deformation component in pressure welding samples of dissimilar cast and wrought nickel-based alloys

Akhunova¹,

Galieva²,

Дроздов³

et al. 2016

LoM

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A material plastic flow finite-element modeling during pressure welding (PW) of two-element and three-element samples was carried out for dissimilar wrought (EP975) and cast intermetallic (VKNA-type) alloys at 1125°C and 10-4 s-1 initial strain rate. The finite-element modeling was performed in a two-dimensional setup (plane strain). In the two-element samples case, the top element was ultrafine grained EP975 and the bottom one was VKNA-25. The top and bottom elements of the threeelement samples were made from VKNA-25 while the intermediate element was ultrafine-grained EP975. The geometry in the X and Y directions were 40.5 and 5 mm for the EP975 samples and 40.5 and 3 mm for the VKNA-25 samples respectively. Experiments on PW intermetallic Ni 3 Al alloy and heat-resistant nickel alloy EP975 with ultrafine-grained (UFG) structure were carried out. Samples were parallelepipeds of size 10×40×3 mm 3 and 10×40×5 mm 3 respectively. PW was carried out at 1125°C. Several combinations of welded sample surfaces with flat and grooved relief were considered. The relief made on both welded surfaces was equivalent to increase of friction between them. This results in a shear deformation reduction near the contact surfaces and degrades the welding quality as compared to the flat surfaces conventional welding. Relief applied only to one of the elements being welded results in a more efficient welding process since active deformation zones are created in the central zone, where in the other samples stagnant zones are observed. There are no deformation peculiarities in PW of the three-element samples, compared to two-element sample.

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Temperature Dependence of the Magnetization of the Ni52Mn24Ga24 Alloy in Various Structural States

Cited by 8 publications

References 9 publications

Molecular dynamics simulation of the effect of dislocations on the martensitic transformations in a two-dimensional model

Molecular dynamics simulation of the effect of dislocations on the martensitic transformations in a two-dimensional model

Two-dimensional model of the ordered alloy for the investigation of martensitic transformations

The role of shear deformation component in pressure welding samples of dissimilar cast and wrought nickel-based alloys

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