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Dive into the research topics where A.D. Pogrebnjak is active.

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Featured researches published by A.D. Pogrebnjak.


Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms | 1998

A review of mixing processes in Ta/Fe and Mo/Fe systems treated by high current electron beams

A.D. Pogrebnjak; S. Bratushka; V.I. Boyko; I.V. Shamanin; Yu.V. Tsvintarnaya

The review deals with a brief analysis of results on mixing in Ta/Fe and Mo/Fe systems using high current electron beams. Theoretical models of mass-transfer, which the authors used for the interpretation of experimental results obtained after pulsed beam treatment, have been considered. The formation of amorphous phase, intermetalloid phases Fe2Ta, as well as the formation of high dislocation density up to 5×1010 cm−2 have been shown. A non-equilibrium metastable phase Fe4Mo(Fe80Mo20) and, possibly Fe96Mo4, is formed as a result of irradiation of Mo/Fe system. The formation of a surface complex structure and near surface layers result in an enhancement of corrosion resistance, an increased depth of the hardened layer and a higher resistance to brittle damaging.


Russian Chemical Reviews | 2014

The structure and properties of high-entropy alloys and nitride coatings based on them

A.D. Pogrebnjak; A.A. Bagdasaryan; I. V. Yakushchenko; V. M. Beresnev

The results of studies on the regularities of structure formation and properties of high-entropy alloys prepared by different methods are analyzed and generalized. Specific features of the synthesis of nitride coatings based on multicomponent alloys are considered. Main physicomechanical properties of the coatings of different elemental composition deposited in different manner were compared. The bibliography includes 229 references.


Science and Technology of Advanced Materials | 2014

First-principles quantum molecular dynamics study of Ti x Zr 1 x N(111)/SiN y heterostructures and comparison with experimental results

V.I. Ivashchenko; S. Veprek; A.D. Pogrebnjak; Bogdan Postolnyi

Abstract The heterostructures of five monolayers B1–TixZr1−xN(111), x = 1.0, 0.6, 0.4 and 0.0 (where B1 is a NaCl-type structure) with one monolayer of a Si3N4-like Si2N3 interfacial layer were investigated by means of first-principles quantum molecular dynamics and a structure optimization procedure using the Quantum ESPRESSO code. Slabs consisting of stoichiometric TiN and ZrN and random, as well as segregated, B1–TixZr1−xN(111) solutions were considered. The calculations of the B1–TixZr1−xN solid solutions, as well as of the heterostructures, showed that the pseudo-binary TiN–ZrN system exhibits a miscibility gap. The segregated heterostructures in which Zr atoms surround the SiyNz interface were found to be the most stable. For the Zr-rich heterostructures, the total energy of the random solid solution was lower compared to that of the segregated one, whereas for the Ti-rich heterostructures the opposite tendency was observed. Hard and super hard Zr–Ti–Si–N coatings with thicknesses from 2.8 to 3.5 μm were obtained using a vacuum arc source with high frequency stimulation. The samples were annealed in a vacuum and in air at 1200 °C. Experimental investigations of Zr–Ti–N, Zr–Ti–Si–N and Ti–Si–N coatings with different Zr, Ti and Si concentrations were carried out for comparison with results obtained from TixZr1−xN(111)/SiNy systems. During annealing, the hardness of the best series samples was increased from (39.6 ± 1.4) to 53.6 GPa, which seemed to indicate that a spinodal segregation along grain interfaces was finished. A maximum hardness of 40.8 GPa before and 55 GPa after annealing in air at 500 °C was observed for coatings with a concentration of elements of Si  (7–8) at.%, Ti  22 at.% and Zr  70 at.%.


Physics Letters A | 1998

Evolution of vacancy defects and dislocations in surface layers of iron as a result of pulsed electron beam treatment

A.D. Pogrebnjak; A.D. Mikhaliov; N.A. Pogrebnjak; Yu.V. Tsvintarnaya; V.I. Lavrentiev; M. Iljashenko; A.N. Valyaev; S. Bratushka; Antonio Zecca; R Sandrik

Abstract Using a micro-beam of ions (PIXE, RBS), a slow positron beam, measurements of positron lifetime, TEM and SEM techniques, formation of vacancy defects and dislocations has been found in a near-surface iron layer as a result of pulsed electron beam treatment. It has been shown that as a result of the HCEB treatment regions of a low local electron density are formed, which seem to be “embryos” for craters. In spite of the crater formation and high dislocation density (exceeding 10 10 cm −2 ) in a near-surface layer, we found a decrease in wear resistance to dry friction and an increase in microhardness.


Physics Letters A | 2000

Certain features of high-dose and intensive implantation of Al ions in iron

A.D. Pogrebnjak; O.G Bakharev; N.A. Pogrebnjak; Yu.V. Tsvintarnaya; V.T Shablja; R Sandrik; Antonio Zecca

Abstract Using a proton microbeam PIXE and RBS, a formation of local surface segregations of aluminum in an iron layer has been found, for the first time, at an initial stage of high-dose intensive implantation (from 8×1016 to ×1017 cm−2). Using a slow positron beam, a profile of vacancy defects, which depth is comparable to a depth profile of Al ions implanted into iron with 5×1017 cm−2 has been measured. Complex carbides (Fe3Al)C and Fe3C have been found in a near surface layer (TEM measurements) as well as segregations of an ordered phase Fe3Al (which with a dose increased are partially amorphized). In addition, high dislocation density of 1.2×1010 cm−2 has been found in the near surface layer, and fields of elastic stresses are formed, which results in the increased friction wear resistance and microhardness.


Technical Physics Letters | 2014

The effect of nanolayer thickness on the structure and properties of multilayer TiN/MoN coatings

A.D. Pogrebnjak; V. M. Beresnev; O.V. Bondar; G. Abadias; Patrick Chartier; B. A. Postol’nyi; A. A. Andreev; O. V. Sobol

The effect of nanolayer thickness on the structure and properties of nanocomposite multilayer TiN/MoN coatings is revealed. The multilayer (alternating) TiN/MoN coatings are prepared by the Arc-PVD method. The selected thickness of the nanolayers is 2, 10, 20, and 40 nm. The formation of two phases—TiN (fcc) and γ-Mo2N—is found. The ratio of Ti and Mo concentrations varies with varying layer thickness. The maximum hardness value obtained for different thicknesses of the layers does not exceed 28–31 GPa. The stability of TiN/MoN during cutting and tribological tests is significantly higher than that of products with TiN coatings. The nanostructured multilayer coatings with layer thicknesses of 10 and 20 nm exhibit the lowest friction coefficient of 0.09–0.12.


Technical Physics | 2010

Thermal stability of the phase composition, structure, and stressed state of ion-plasma condensates in the Zr-Ti-Si-N system

V. M. Beresnev; O. V. Sobol; A.D. Pogrebnjak; P. V. Turbin; S. V. Litovchenko

The results of studying the effect of high-tempera ture annealing in vacuum and in air on the phase composition, structure, and stressed state of ion-plasma condensates in the Zr-Ti-Si-N system are reported. In going from air annealing to vacuum annealing, the amount of active oxygen atoms decreases and the phase composition of the condensate remains stable to 1000°C or higher. A change in the crystal phase composition shows up, for the first place, in the crystallization of silicon nitride with the intense formation of hexagonal β-Si3N4 crystallites and also in the feeble formation of ZrO2 dioxide. The latter process does not lead to the decomposition of the (Zr, Ti)N solid solution: it merely increases the partial concentration of the titanium component.


Physics of the Solid State | 2015

Influence of implantation of Au− ions on the microstructure and mechanical properties of the nanostructured multielement (TiZrHf VNbTa)N coating

A.D. Pogrebnjak; I. V. Yakushchenko; O.V. Bondar; O. V. Sobol; V. M. Beresnev; K. Oyoshi; H. Amekura; Y. Takeda

It has been found that the phase with the fcc lattice of the NaCl structural type is formed due to the vacuum-arc deposition of the nanostructured multicomponent (TiZrHfVNbTa)N coating. Implantation of negative Au− ions with a dose of 1 × 1017 cm−2 leads to the formation of a disordered polycrystalline structure without a preferred orientation of the fcc phase and nanocrystallites from 5–7 to 1–3 nm is size, which are dispersed in a layer up to 35 nm in depth. Nanohardness increases to 33 GPa, and the Vickers hardness reaches 51 GPa. Gold nanoclusters are formed in the near-surface region, while the fcc lattice and the formation of local Au regions are observed in the coating itself. Fragments with the hcp lattice are formed at depths above 180 nm because of the low nitrogen concentration.


Technical Physics Letters | 2003

Mass transfer and doping during electrolyte-plasma treatment of cast iron

A.D. Pogrebnjak; O. P. Kul’ment’eva; A. P. Kobzev; Yu. N. Tyurin; S. I. Golovenko; A. G. Boiko

The surface and subsurface layers of cast iron articles upon electrolyte-plasma treatment (EPT) were studied for the first time by a combination of methods, including Rutherford backscattering, elastic recoil detection analysis, X-ray diffraction, optical metallography, and microhardness measurements. It was found that tungsten and copper ions are incorporated into the surface layers of the metal. Total thickness of an EPT-hardened layer is about 3 mm, the maximum hardness (up to 7000 MPa) being observed at a depth from 1 to 2.5 mm. The X-ray diffraction analysis (i) shows that the EPT-hardened layer comprises a mixture of α and γ phases, (ii) indicates the formation of a fine-grained martensite structure with high dislocation density (above 1012 cm−2) and an oxide (FeO) phase, and (iii) reveals mass transfer involving the doping elements (W and Cu).


Surface & Coatings Technology | 1998

Mixing of Ta-Fe and Mo-Fe systems using a low-energy, high-current electron beam

A.D. Pogrebnjak; O.G. Bakharev; V.V. Sushko; S. Bratushka; A.D. Mikhaliov; Yu.F. Ivanov; A. B. Markov; D.I. Proskurovskiy; V.P. Rotstein; A.N. Valyaev

Abstract Rutherford backscattering spectroscopy, Auger electron spectroscopy, conversion electron Mossbauer spectroscopy, transmission microscopy and scanning electron microscopy showed that treatment of a thin or Mo film/α-Fe substrate system with a high-current electron beam (HCEB) of an energy density of 2.3–5.2 J cm2 resulted in a mixing of the systems components. In the energy range 2.3–3.3 J cm2 in the HC in the HCEB-irradiated Ta-Fe system, we found a mixed layer of a thickness of about 100 nm, which we relate to the formation of a stable compound (Fe2TTa, FeTa) and a non-equilibrium Fe5TTa2 compound. The irradiated surface is not uniform, being composed of inclusions of a spherical form (300 nm diameter), solid-solution Fe(Ta) and amorphous-phase Fe-Ta. An increase in the pulse number results in the formation of the volume fraction FeTa and a dislocation density of 5×100cmcm2. It has b. It has been shown that HCEB irradiation of the Mo-Fe system with energy flow densities of 2.3–3.3 J cm2 produced a mixed layer of a thickness of up to 150 nm, and a non-equilibrium Fe4MMo compound (Fe0MoMo0)) was formed. On increasing the energy density to 4.2 J cm2, we obser, we observed partial Mo ablation and the formation of a mixed compound with a Mo concentration of several at.%.

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G. Abadias

University of Poitiers

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Stefan Jurga

Adam Mickiewicz University in Poznań

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Emerson Coy

Adam Mickiewicz University in Poznań

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Y. Takeda

National Institute for Materials Science

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