Martensitic Transformation in Spark Plasma Sintered Compacts of Ni-Mn-Ga Powders Prepared by Spark Erosion Method in Cryogenic Liquids

Ochin, P.; Gilchuk, A.V.; Monastyrsky, G.E.; Koval, Yu. N.; Shcherba, А.А.; Zaharchenko, Sergij N.

doi:10.4028/www.scientific.net/msf.738-739.451

Cited by 22 publications

(7 citation statements)

References 6 publications

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“…Such a micron-sized hollow particle is shown on Fig. 8 , but much more number of the micron-sized hollow particles has been observed in [ 13 – 15 , 30 ]. A drastic difference between the cryogen gas solubility in molten droplets and in the solid phase, which is assumed in [ 14 , 15 ], promotes the explosive boiling mechanism.…”

Section: Resultsmentioning

confidence: 97%

Nanoparticles formation mechanisms through the spark erosion of alloys in cryogenic liquids

Monastyrsky¹

2015

Nanoscale Res Lett

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Mechanisms of the formation of nanoparticles of some B2 shape memory intermetallic compounds, glass-forming Zr-based alloy, and pure Ti obtained by spark erosion method in liquid nitrogen and argon are considered. One of peculiarity is a foam-like structure, which covers the surface of micron-sized particles that appear during spark erosion. Such morphology is related to the nanosized particles gathered in agglomerates. Detailed examination of those particles allows proposed several mechanisms of their formation. The mechanisms explains two kinds of nanosized particles: particles of several tens and even hundreds of nanometers are formed due to explosion of molten droplets while the smaller particles having in turn a different structure and morphology are formed as a result of condensation of evaporated constituents under different conditions. The latter have the composition usually different from the target composition while the composition of the former is very close to the target (master alloy) composition.

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Section: Resultsmentioning

confidence: 97%

Nanoparticles formation mechanisms through the spark erosion of alloys in cryogenic liquids

Monastyrsky¹

2015

Nanoscale Res Lett

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“…The route of the elaboration and thermal treatment of the sparkerosion powders with a nominal composition Ni49.0-Mn28.5-Ga22.5 (at.%) has described in details elsewhere [8,12]. Alloy with a nominal composition Ni63-Al37 (at.%) were arc-melted and moulded into the bars with the diameter of 4 mm and the length of 12 cm.…”

Section: Methodsmentioning

confidence: 99%

“…In our previous communication [8], the results of spark-plasma sintering of Ni-Mn-Ga spark-erosion powder and the peculiarities of the martensitic transformation in compacts are described. As is shown, the morphology and microstructure of spark-erosion particles are very similar to gas atomized powders.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Testing of the Shape-Memory Materials Synthesized by a Plasma-Spark Method

Monastyrsky¹,

Gilchuk²,

Ochin³

et al. 2016

Metallofiz. Noveishie Tekhnol.

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Compression tests are carried out at room temperature with the as-cast and spark-plasma sintered (SPS) specimens of Ni49.0-Mn28.5-Ga22.5 (at.%) and Ni63-Al37 (at.%) alloys. For both systems, ductility of the SPS compacts increases more than by one order of magnitude. Compressive strength of Ni-Mn-Ga alloy increases from 180-240 MPa for induction melted specimens to 510-815 MPa for spark-plasma sintered specimens, depending on the regimes of processing, and for Ni-Al alloy, from 760 to 1310 MPa. Fracture stress of Ni-Mn-Ga and Ni-Al specimens raise from 185-215 to 1170 MPa and from 790 to 1870 MPa, respectively. The SEM and XRD investigations reveal that sintered samples of both systems have a composite structure, which contains the micron-size metallic particles bound by the binder phase. This phase consists of Ni 3 Al and Al 2 O 3 phases in case of Ni-Al alloy and consists of MnO with apparently small amount of Ni 3 Ga phase in case of Ni-MnGa alloy. As assumed, this phase strengthens the grain boundaries. This one, in conjunction with reduction of the grain size, the manifold morphology of the Ni-Mn-Ga specimens consolidated from the hollow particles, the presence of extra ductile -phase in Ni-Al particles, provides the enhancing mechanical properties of alloys fabricated by means of the SPS method. Ga для стопу Ni-Mn-Ga. Передбачається, що ця фаза зміцнює межі зерен. Це разом із зменшенням розміру зерна, а також багатозв'язною морфологією зразків Ni-Mn-Ga, консолідованих із порожнистих части-нок, та наявністю пластичної -фази в частинках Ni-Al покращує меха-нічні властивості стопів, одержаних плазмово-іскровою методою. Випробування на стиснення було виконано при кімнатній температуріИспытания на сжатие были выполнены при комнатной температуре для образцов сплавов Ni49,0-Mn28,5-Ga22,5 (ат.%) и Ni63-Al37 (ат.%), как для выплавленных, так и полученных плазменно-искровым методом (ПИМ). Для обеих систем пластичность ПИМ-образцов возрастает более чем на порядок по сравнению с исходными. Прочность на сжатие сплава Ni-Mn-Ga увеличивается от 180-240 МПа для выплавленных образцов до 510-815 МПа для ПИМ-образцов в зависимости от режимов обработки, для сплава Ni-Al -от 760 до 1310 МПа. Напряжение разрушения образ-цов Ni-Mn-Ga увеличивается от 185-215 до 1170 МПа, а для образцов Ni-Al -от 790 до 1870 МПа. Спечённые образцы обеих систем имеют композитную структуру, образованную из металлических частиц мик-ронных размеров, скреплённых связующей фазой, состоящей из Ni 3 Al и Al 2 O 3 для сплава Ni-Al и из MnO с небольшим количеством Ni 3 Ga для сплава Ni-Mn-Ga. Предполагается, что эта фаза укрепляет границы зё-рен. Это вместе с уменьшением размера зерна, а также многосвязной морфологией образцов Ni-Mn-Ga, консолидированных из полых частиц, и наличием пластической -фазы в частицах Ni-Al улучшает механиче-ские свойства сплавов, полученных плазменно-искровым методом.

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“…[1][2][3]. Such EDIs with reservoir capacitors are successfully used for the implementation of modern spark-erosion electro-technologies for the production of finely dispersed metal powders with unique performance properties using EDIs for volumetric electro-spark dispersion (VESD) of a layer of metal granules in flowing low-conductive (preferably dielectric) liquids in the interelectrode gap (IEG) [4,5].…”

mentioning

confidence: 99%

Improving the Dynamic Characteristics of Electric Discharge Installations, Which Are Significantly Distant From the Spark-Erosion Load

et al. 2022

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The paper identifies the features of the influence of the characteristics of different connecting conductors on the dynamic characteristics of electric discharge installations (EDIs), which are distant significantly (several meters) from the spark-erosion load. In the electric spark production of dispersed powders, such a load is the interelectrode gap (IEG) in the technological dispersion apparatus (TAD), filled with a layer of metal granules and a low-conductive (preferably dielectric) flowing liquid. The influence of the design parameters of such long connecting conductors as twisted pair, litzendraht with bifilar winding of conductors and coaxial cable on the dynamic characteristics of the indicated EDIs (including on the average rates of rise and fall of the discharge pulse current) is experimentally investigated. It is substantiated that the use of power coaxial cables with modern cross-linked polymer electrical insulation is practically the most expedient for connection of significantly distant TAD under the condition of insignificant (up to 0.5 μH) self-inductance of EDIs. References 11, figures 4, tables 3.

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Martensitic Transformation in Spark Plasma Sintered Compacts of Ni-Mn-Ga Powders Prepared by Spark Erosion Method in Cryogenic Liquids

Cited by 22 publications

References 6 publications

Nanoparticles formation mechanisms through the spark erosion of alloys in cryogenic liquids

Nanoparticles formation mechanisms through the spark erosion of alloys in cryogenic liquids

Mechanical Testing of the Shape-Memory Materials Synthesized by a Plasma-Spark Method

Improving the Dynamic Characteristics of Electric Discharge Installations, Which Are Significantly Distant From the Spark-Erosion Load

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