E. P. Elsukov

Russian Academy of Sciences, Moskva, Moscow, Russia

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Publications (54)29.37 Total impact

  • M. A. Eremina, S. F. Lomaeva, E. P. Elsukov
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    ABSTRACT: Structural and phase transformations that occur during mechanical alloying (MA) and subsequent annealing of nanocrystalline Cu-Cr-C alloys obtained from copper and chromium powders and graphite or xylene as the source of carbon have been studied. It is shown that, when using graphite, a supersaturated Cu(Cr) solid solution and an X-ray amorphous Cr-C phase are formed during MA. Heat treatment leads to their decomposition and the appearance of Cr3C2 in the nanocrystalline copper matrix. When xylene is used as the source of carbon, no strongly supersaturated Cu(Cr) solid solution and no X-ray amorphous Cr-C phase are formed, but the same volume fraction of chromium carbide, i.e., 20–24 vol %, appears. When graphite is used, the carbide is formed after shorter times of MA.
    The Physics of Metals and Metallography 11/2013; 114(11):928-934. · 0.57 Impact Factor
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    ABSTRACT: Mössbauer spectroscopy and X-ray diffraction have been used to study the sequence of solidstate reactions that occur upon the mechanical alloying of mixtures of Si and Fe powders taken in an atomic ratio of 70: 30 in a planetary ball mill. In the course of the formation of a nanocrystalline state, the interpenetration of Si atoms into Fe particles and of Fe atoms into Si particles occurs. In the Si particles, clusters with a local neighborhood of Fe atoms that is characteristic of the deformed α-FeSi2 phase are formed. In the Fe particles, clusters of the ɛ-FeSi and the β-FeSi2 type arise. With increasing time of mechanical treatment, second phases of α-FeSi2 in Si particles and of ɛ-FeSi and β-FeSi2 in Fe particle are formed. In the latter case, a reaction ɛ-FeSi + Si → β-FeSi2 occurs up to the complete disappearance of the ɛ-FeSi phase if the mixture under study is not contaminated by the material of the vessel (Fe) and balls.
    The Physics of Metals and Metallography 11/2013; 114(11):953-961. · 0.57 Impact Factor
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    ABSTRACT: Using X-ray diffraction analysis, Mössbauer spectroscopy, and magnetic measurements, the structure, parameters of hyperfine interactions, localization of Mn atoms in the lattice, coercive force, and specific saturation magnetization have been investigated in the mechanically alloyed and annealed cementite (alloyed with manganese) of compositions (Fe1 − x Mnx )3C (x = 0–0.12). It has been shown that strongly deformed cementite resides in the low-coercivity state and, after annealing in the vicinity of 500°C, in the high-coercivity state. Alloying with manganese reduces the coercive force, the specific saturation magnetization, and the Curie temperature of cementite. Inhomogeneities of the distribution of manganese atoms indicate the temperature dependence of the coercive force of mechanically alloyed and annealed cementite samples.
    The Physics of Metals and Metallography 12/2012; 113(12). · 0.57 Impact Factor
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    ABSTRACT: Different procedures for analysis of particle sizes by the X-ray diffraction method are compared by the example of nanoparticles of nickel and iron(3+) oxide (Fe2O3). A modified Warren-Averbach method is proposed for the analysis of the X-ray diffraction line profile based on the approximation by the Voigt function, which yields stable solutions, and the efficiency of the method is shown. The analysis within the frame-work of the Warren-Averbach method makes it possible to restore the distribution function of nanoparticles (crystallites) over true diameters, which satisfactorily correlates with electron microscopy data. The applicability of the Warren-Averbach method to the estimation of crystallite sizes by the analysis of a single diffraction line is substantiated. The range of the applicability of the Scherrer, Williamson-Hall, Warren-Averbach, and modified Warren-Averbach methods to the substructure analysis by the X-ray diffraction is determined as depending on the method of nanostructure formation.
    Colloid Journal 11/2012; 74(6). · 0.63 Impact Factor
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    ABSTRACT: Transformations realized in mechanosynthesized amorphous-nanocrystalline Fe(75)C(25 − x)Si(x) (0 ≤ x ≤ 10 at %) alloys during heating have been studied using dynamic magnetic susceptibility measurements, X-ray diffraction, and metallography. In contrast to mechanosynthesized alloys consisting of α-Fe, Fe3C, and amorphous phases, the annealed alloys with x > 5 at % were found to exhibit the formation of an additional phase such as Fe5SiC. After heating to 700 and 800°C, the powder particles of alloys contain a large amount of uniformly distributed graphite particles of ∼0.5 μm in size. The formation of particles results from the cementite decomposition, which is accelerated at the expense of partial silicon dissolution in cementite and in the presence of α-Fe nanograins as well.
    The Physics of Metals and Metallography 04/2012; 113(4). · 0.57 Impact Factor
  • E. P. Elsukov, A. V. Protasov
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    ABSTRACT: Using X-ray diffraction, Mössbauer spectroscopy, and Auger spectrometry, it has been established that oxygen affects the sequence of solid-state reactions upon mechanical alloying of two types of powders mixtures consisting of an Mo/O composite and Fe with the elemental (atomic) ratios 74.4: 6.7: 18.9 (type 1) and 70.3: 11.7: 18 (type 2). For the samples of both types the process begins with the formation of a nanostructure in Mo and penetration of Fe atoms along oxygen-saturated grain boundaries. The feasibility of two types of reactions depending on the oxygen content has been considered. In the samples of the first type, a reaction Mo/O + Fe → bcc Mo + bcc Mo-O-Fe → bcc Mo74.4O6.7Fe18.9 occurs. The final product is assumed to be a supersaturated solid solution in which O atoms are located in interstitial positions (lattice interstices) and Fe atoms in substitutional positions (lattice sites). For the samples of the second type, an appreciably different reaction has been suggested: Mo/O + Fe → bcc Mo + hcp Mo63O15Fe22 → bcc Mo81Fe19 + Am Mo31O52Fe17, where Am is an amorphous phase. The correlation (established by Butaygin and Povstugar (Dokl.-Chem. 398 (Part 2), 196–199 (2004)) between the rate of the consumption of the second component and the ratio of the yield strengths of the base (Mo) and second (Fe) elements has been confirmed.
    The Physics of Metals and Metallography 01/2011; 111(5):503-512. · 0.57 Impact Factor
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    ABSTRACT: Two types of solid state reactions that occur during mechanical alloying of Mo/O --20 at. % Fe system with various oxygen concentrations were studied by Moessbauer spectroscopy and X-ray diffraction. The first type of solid state reaction, Mo/O+Fe{yields}bcc Mo(O)-Fe, was observed for Mo samples with 8 at. % of oxygen. The second type of solid state reaction proceeds as Mo/O+Fe{yields}bcc Mo(O)-Fe+hcp Mo(O)-Fe{yields}bcc Mo(O)-Fe+Am Mo(O)-Fe for Mo samples with 14 at. % of oxygen and 1.6 at. % of MoO{sub 3} phase. The assumption about correlation between the second component dissolution rate and mixture components yield point ratio is confirmed.
    AIP Conference Proceedings 07/2010; 1258(1).
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    ABSTRACT: The sequence of solid state reactions upon the mechanical alloying of Mo and Fe powders with an 80: 20 atomic ratio was established by means of Mössbauer spectroscopy and X-ray diffraction. At the first stage, a nanostructure and Mo63Fe37 hexagonal close packed (HCP) phase are formed in Mo body-centered cubic lattice (BCC) particles. At the second stage, a body-centered cubic lattice of Mo-Fe solid solution is formed. The process is accompanied by the formation of a minor amount (about 20%) of X-ray amorphous phase.
    Bulletin of the Russian Academy of Sciences Physics 01/2010; 74(3):339-342.
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    ABSTRACT: Results of Mössbauer and magnetic studies of partially ordered alloys Fe100 − x Al x (25 x < 35 at %) are discussed depending on the temperature and applied magnetic field. Two variants of the interpretation of the temperature behavior of magnetization and average hyperfine magnetic field at 57Fe nuclei in the model of a collinear magnet with magnetic inhomogeneities of a nanometer range are suggested. In the first variant, the existence of clusters with magnetic moments oriented parallel and antiparallel to the total magnetization is assumed. Temperature anomalies, such as the nonmonotonic dependence of magnetization and hyperfine magnetic field in the temperature range of 100–200 K, are explained at a qualitative level by the stabilization of relaxation phenomena in clusters due to Stoner-type spin excitations. The second variant is based on the assumption of a change in the orientation of spins antiparallel to the magnetization with increasing temperature.
    The Physics of Metals and Metallography 01/2010; 109(5):417-426. · 0.57 Impact Factor
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    ABSTRACT: Differential scanning calorimetry, X-ray diffraction, Mössbauer spectroscopy of 57Fe nuclei, magnetic measurements, and different heat treatments have been used to study the sequence and mechanisms of solid-state reactions in the Fe-Si-C amorphous alloy in the course of the structure transition to equilibrium. Three stages of structural and phase transformations have been found; these are the structural relaxation, formation of an Fe5SiC silicocarbide, and its decomposition. It has been shown that the second and third stages occur during isochronous annealing within sufficiently narrow temperature ranges of 380–405 and 530–555°C, respectively. The kinetics of the decomposition of the metastable Fe5SiC silicocarbide and the formation of the ordered Fe-Si alloy during isothermal annealing has been studied.
    The Physics of Metals and Metallography 01/2010; 110(6):542-552. · 0.57 Impact Factor
  • E. P. Elsukov, A. V. Protasov
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    ABSTRACT: The localization of Fe atoms in the process of mechanical alloying of a Mo powder composite with 8 at % O at boundaries of the bcc Mo grains has been investigated by Mössbauer spectroscopy on impurity 57Fe isotope atoms (1 at %), X-ray diffraction, and Auger spectrometry. The process begins with the formation of a nanostructure (∼10 nm) in bcc Mo and ends with the formation of a bcc supersaturated solid solution with O atoms at interstitial positions and Fe atoms at substitutional positions. The presence of oxygen in the boundaries of bcc Mo grains leads to an extraordinarily large isomer shift (2 mm/s with respect to α-Fe) for the grainboundary component in the Mössbauer spectrum. This circumstance makes it possible to consider 57Fe-O complexes as new probes for studying grain boundaries of powder nanocrystalline materials. As a result, the following three structural components have been identified in the mechanically activated system: a grain boundary and distorted near-boundary regions with the common name interface and a grain with the perfect (defect-free) structure. For powder nanocrystalline (∼10 nm) materials subjected to intense mechanical treatment in a planetary ball mill, the widths of the unrelaxed grain boundary and interface average over the entire volume of particles have been experimentally estimated as 0.2 and 1 nm, respectively.
    JETP Letters 01/2010; 92(11):746-750. · 1.52 Impact Factor
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    ABSTRACT: Structural and phase transformations that occur in Fe(Fe3C, Fe3SiC)-SiO2 (amorphous quartz) systems during mechanical alloying in an Ar atmosphere and in air have been studied by X-ray diffraction, Mössbauer spectroscopy, IR spectroscopy, electron microscopy, and magnetometry. It has been shown that the mechanoactivation treatment leads to the formation of isolated particles 2–20 nm in size with a complex phase composition (Fe, FeSi alloy, oxides, silicates, and carbides), which depends on the milling atmosphere. It has been found out that the magnetic properties of such systems strongly depend on the oxygen and carbon compounds existing in the system, which cannot be detected by X-ray diffraction, but their presence is testified by the data of Mössbauer spectroscopy.
    The Physics of Metals and Metallography 01/2010; 109(5):534-546. · 0.57 Impact Factor
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    ABSTRACT: Double electromagnetic acoustic transformation method was used to study dynamic magnetoelastic properties of the Fe73.7Cu1.0Nb3.2Si12.7B9.4 amorphous alloy subjected to crystallization annealing at different temperatures. Anomalous variations in the differential magnetostriction and ultrasound damping and velocity were found. According to Mössbauer spectroscopy data, they are related to the formation of a component of magnetic moments that is perpendicular to the ribbon surface.
    The Physics of Metals and Metallography 03/2009; 107(3). · 0.57 Impact Factor
  • L. S. Vasil’ev, I. L. Lomaev, E. P. Elsukov
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    ABSTRACT: The kinetic features of dissolution of foreign inclusions in the bulk of nanostructured metals upon plastic deformation have been discussed. It has been shown that the rate of dissolution of inclusions substantially depends on the character of structural transformations in the subsystem of intercrystallite boundaries of nanomaterials. Equations that determine the kinetics of dissolution of chemical compounds of metals depending on the rate of structural transformations in intercrystallite boundaries upon deformation have been obtained. The behavior of the kinetic curves of dissolution has been described qualitatively. Numerical estimates of the time of dissolution of inclusions Fe3C and Fe2B in steels are given which are in satisfactory agreement with experimental data on the mechanical alloying of iron with nonmetals in ball planetary mills.
    The Physics of Metals and Metallography 01/2009; 107(2):141-150. · 0.57 Impact Factor
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    ABSTRACT: Principal factors determining the microwave-absorption material parameters (shape, size, and chemical and phase compositions of the particles) and their dispersion relations in a range from 0.1 to 3 GHz were determined for composites containing milled Fe particles as the filling agent. The basic physical mechanisms of the effect of the aforementioned factors were assumed to be the domain-wall resonance and ferromagnetic resonance.
    The Physics of Metals and Metallography 10/2008; 106(5):465-471. · 0.57 Impact Factor
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    ABSTRACT: The transverse magnetoresistance and the Hall effect of Fe(100 -x)Al(x) ordered alloys with x = 26.5-34.1 at. % are studied at temperatures of 77 and 295 K. No saturation is found in the field dependences up to 17 kOe. The magnetoresistance is negative, depends nonmonotonically on the Al concentration, and reaches a maximum vertical bar Delta R/R vertical bar = 1.6% in the concentration range from 28 to 30 at. %. The coefficient of the anomalous Hall effect depends nonlinearly on the Al concentration and resistivity: it increases to a lesser extent as compared to the resistivity at x = 26-30 at. % and decreases with increasing resistivity at x > 30 at. %. An explanation is proposed for the observed anomalies in the magnetotransport properties in the framework of the model developed for the inhomogeneous magnetic microstructure of the Fe(100 -x)Al(x) ordered alloys.
    Physics of the Solid State 06/2008; 50(6):1071-1075. · 0.77 Impact Factor
  • E. P. Elsukov, G. N. Konygin, V. E. Porsev
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    ABSTRACT: X-ray diffraction, Mössbauer spectroscopy, and magnetic measurements were used to study the magnetic properties and the parameters of hyperfine interactions in the nanocrystalline (with a grain size less than 10 nm) and microcrystalline alloys Fe90Ge10, Fe77Al23 and pure α-Fe. It has been established that the nanocrystalline state does not affect the formation of the saturation magnetization, Curie temperature, isomeric shift, and hyperfine magnetic field. No additional sextets in the Mössbauer spectra and no additional features in the temperature dependences of dynamic magnetic susceptibility of the alloys investigated have been revealed. In the Mössbauer spectrum of pure nanocrystalline iron, a slight line broadening (∼20%) is observed.
    The Physics of Metals and Metallography 02/2008; 105(2):141-149. · 0.57 Impact Factor
  • I. L. Lomaev, E. P. Elsukov
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    ABSTRACT: The possible mechanisms of the strain-induced dissolution of phases in metals subjected to severe plastic deformation have been investigated. The mechanisms of impurity absorption by new interphase and grain boundaries formed under severe plastic deformation and the high-temperature phase at its strain-induced nucleation are shown to be the most effective. The possible dislocation mechanisms of phase dissolution are low-efficient. In carbon steels, the strain-induced dissolution of cementite continues until the limiting nanostructure absorbs about 10–12 at % carbon from the mixture volume.
    Bulletin of the Russian Academy of Sciences Physics 01/2008; 72(10):1419-1422.
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    ABSTRACT: The effect of the chemical composition and structural and morphological features of Fe and Fe87Si13 powders milled in an inert atmosphere of Ar and a 3% solution of oleic acid in heptane (H + OA) on the magnetostatic and microwave properties has been studied in this work. Irrespective of the milling medium, all the samples were nanocrystalline. The powder particles obtained in Ar have a stonelike shape; those obtained in H + OA, have a platelike (flaky) shape. The effect of the particle shape manifested itself in the processes of magnetization and in the qualitative and quantitative type of the frequency dependences of the dielectric permittivity and magnetic permeability in a frequency range from 0.1 to 3 GHz.
    The Physics of Metals and Metallography 08/2007; 104(3):248-256. · 0.57 Impact Factor
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    ABSTRACT: The study is conducted of thin Fe–N films produced by magnetron sputtering on mylar substrate. The correlations between morphology, structure, and magnetic static and dynamic properties of the films are found. The films under study have a columnar morphology. Both the average granule size and the length-to-width ratio of the granules increase with the film thickness that causes an increase of the effective anisotropy field. A small variation of nitrogen fraction in Ar+N2 gas mixture in the sputtering chamber allows the location of magnetic loss peak to be controlled within the frequency range of 1–5 GHz. Therefore, the frequency dependence of permeability is determined not only by the crystalline structure and composition of the film but also by its morphology, thickness, and effective magnetic anisotropy. In particular, with the fixed concentration of nitrogen in the film, the frequency dependence of microwave permeability is determined greatly by the distribution of nitrogen atoms over different vacancies in the film structure.
    Physica B Condensed Matter 05/2007; 394(2):159-162. · 1.28 Impact Factor