Structure and Properties of Ni47Mn42In11 Alloy after Severe Plastic Deformation

Kaletina, Yu. V.; Greshnova, Ekaterina; Kaletin, A. Yu.; Frolova, N. Yu.; Pilyugin, V. P.

doi:10.1134/s0031918x19020078

Cited by 11 publications

(2 citation statements)

References 14 publications

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“…Usually, in order to obtain a material with improved properties, it is subjected to various types of thermomechanical treatment (TMT). In the case of Heusler alloys, methods involving large plastic deformations, such as high-pressure torsion [9][10][11][12], rolling [13], upsetting (forging) [14] or extrusion [15][16][17][18][19], are used. In most cases, it leads to a decrease in the functional characteristics.…”

Section: Introductionmentioning

confidence: 99%

Influence of Multi-Axial Isothermal Forging on the Stability of Martensitic Transformation in a Heusler Ni-Mn-Ga Alloy

Musabirov

Safarov

Galeyev

et al. 2021

Trans Indian Inst Met

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The Heusler alloys demonstrate magnetically induced strain and magnetocaloric properties, but the mechanical properties are poor. Therefore, in this work, the influence of thermomechanical treatment on the properties of Ni-Mn-Ga-Si Heusler alloys is considered. The effect of multi-axial isothermal forging on functional properties of the Ni 2.30 Mn 0.73 Ga 0.90 Si 0.07 alloy at 973 K and true strain (e) of 3.9 is presented. It is shown that a unique two-phase microstructure is formed as a result of forging. The large grains in the size range of 100-200 lm are surrounded by a fine-grained structure. The study of the thermomechanical properties by the three-point bend test has shown that the alloy demonstrates a single-stage reversible deformation of 3.1% at a constant stress of 860 MPa as compared to the same alloy in the as-cast condition which shows 2% at 380 MPa. The specimen demonstrates a reversible deformation of 5% without any degradation during thermal cycling (with a base of up to 4000 thermal cycles) under a stress of 550 MPa and up to 5% with degradation occurring at 700 thermal cycles under a stress of 650 MPa. Thus, forging makes it possible to obtain a material with higher operational properties and greater resistance to fracture during multiple cycles of martensitic transformation. In this case, it is possible to obtain anisotropy of properties equal or close to that of the specimen in the as-cast state.

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Section: Introductionmentioning

confidence: 99%

Influence of Multi-Axial Isothermal Forging on the Stability of Martensitic Transformation in a Heusler Ni-Mn-Ga Alloy

Musabirov

Safarov

Galeyev

et al. 2021

Trans Indian Inst Met

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“…On the other hand, no other structure is visible in the diffractograms, demonstrating the absence of any relevant precipitated phase after grinding. The presence of non-modulated tetragonal structures has been previously reported in ternary Ni-Mn-In alloys subjected to severe deformation by high-pressure torsion of 8GPa [321], in grinded Mn 2 Ni 1.34 Sn 0.32 Co 0.34 and in Ni-Mn-In-Co ribbons obtained from melt-spinning technique [296]. This, and the present observation, seems to indicate that the non-modulated tetragonal structure would accommodate better the mechanically-induced stresses than the thermally-induced modulated structures.…”

Section: Hand-crushingmentioning

confidence: 61%

3D-printable composites for magnetic refrigeration based on Ni-Mn-In-Co shape memory alloys

Khanna

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Ni-Mn-Z (Z = In, Sn and Sb) Meta-Magnetic Shape Memory Alloys (MMSMA) have attracted considerable interest in past few decades due to their unique properties associated with a structural transformation called the Martensitic Transformation (MT) between a ferromagnetic austenite phase and weakly magnetic martensitic phase. As a result, a significant drop in magnetization takes place during the martensitic transformation. This feature allows the induction of the transformation by applying a magnetic field, leading to multi-functional properties such as giant magneto-resistance, magnetic shape memory effect, and large inverse magnetocaloric effect. These properties have practical applications in sensing and magnetic refrigeration. The transformation temperatures, magnetization of different phases, entropy change associated with the transformation, and other magneto-structural characteristics determining the functional properties depend on the composition, structure and microstructure of the alloys. While structure and composition (including atomic order) has been extensively analyzed, the role of microstructure has received less attention, despite its potential for controlling the magneto-structural properties. Therefore, this Ph.D. thesis is partially focused on examining the influence of microstructure in meta-magnetic shape memory alloys (specifically in Co-doped Ni-Mn-In) on the magneto-structural properties of micro-particles produced by milling. On the other side, the high MCE found in Ni-Mn-In-Co alloys, make them an attractive material for use in energy-efficient technologies. However, these alloys are very brittle and their use in commercial devices (heat exchanger for example) is limited to simple geometries. To overcome this issue, the present work demonstrates that the use of composites synthesized employing magnetic shape memory micro-particles (functionality) and polymers (geometrical integrity) could be an alternative in the future. The main goal is to be able to obtain microparticles with enhanced functional properties (sizes compatible with a standard 3D-printer nozzle) that can be embedded in a polymer matrix which results in a homogeneous 3D-printable magnetic composite. In this framework, thermo-mechanical treatments were employed (including hand-crushing, ball-milling and thermal annealing) to produce Ni45Co5Mn36.7In13.3 micro-particles. The influence of mechanical milling on the structural and magnetic properties (MT characteristics, crystallographic structures, saturation magnetization and magnetic susceptibility) and on the microstructural parameters such as the internal strains and crystallite sizes of micro-particles has been analyzed. The analysis was carried out in samples milled in both austenite and martensite and subjected to different milling times. A deeper understanding of the role played by the microstructure in the magneto-structural properties of these meta-magnetic shape memory alloys was achieved. For each milling time, the particles have been sieved into different size intervals and a comparative analysis of the magneto-structural and microstructural parameters of the particles within the same size range have been performed. The correlation between the degree of deformation and particle size opened new possibilities to enhance the functional properties of the alloys, where by mere selecting the particle size (irrespective of the duration, time and environment of milling), specific magneto-structural properties and transformation characteristics can be selected. The MCE and relative cooling power have been estimated in those particles suitable for been embedded into printable polymeric filaments. Finally, the fabrication of magnetic Polymer–MMSMA composites was carried out. The effect of the addition of the micro-particles onto the phase transformations and the thermal stability of the polymers has also been analyzed. Filaments were extruded from the composites with the higher particle concentration and mechanical consistency. The printability of these filaments was also demonstrated. As a proof of concept, a 3D printed heat exchanger for magnetic refrigeration was successfully produced using the developed filament.

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