Anatoly M Balagurov

• Prof., Dr.
• Principal Investigator at Joint Institute for Nuclear Research

The phase compositions and structural transformations in the Fe73Ga27 alloy with trace amounts (~ 0.1 − 0.2 at%) of rare earth (RE) elements (Er, Pr, Sm, Tb, Yb) have been analyzed in neutron diffraction experiments performed over a wide temperature range. In the initial as-cast state, all Fe-Ga-RE alloys, except for the composition with Yb, are in...

An analysis of the diffraction spectra of the Fe74Al26 alloy was conducted using a high-resolution neutron diffractometer to determine the size distribution of structurally ordered clusters dispersed within the structurally disordered matrix of the alloy. The Scherrer method was generalized for this purpose, based on the analysis of diffraction pea...

New data on phase states and structural phase transitions in alloys Fe73Ga27 alloys doped with Dy, Er, Tb, and Yb in an amount of ~0.5 at% are presented. Structural data were obtained in neutron diffraction experiments performed with high resolution and in continuous temperature scanning mode during heating to 850°C and subsequent cooling at a rate...

New data on the phase compositions and structural transformations in a number of Fe81Ga19 alloys doped with trace amount (≤ 0.2 at.%) of rare earth elements are presented. The data are obtained in neutron diffraction experiments performed with high resolution and in continuous temperature scanning mode when heated to 900 °C and subsequent cooling....

New data on phase states and structural phase transitions in alloys Fe 73 Ga 27 doped with Dy, Er, Tb, and Yb in an amount of about 0.5 at % are presented. Structural data were obtained in neutron diffraction experiments performed with high resolution and in continuous temperature scanning mode during heating to 850°C and subsequent cooling at a ra...

Currently, the dominant model for the formation of enhanced magnetostriction of Fe-Ga alloys is based on the assumption of the presence of microscopic inclusions with a tetragonal L6 0 structure in the cubic matrix of the alloy. However, no evidence for the presence of this phase in the bulk of the alloys in amounts sufficient to have a noticeable...

Currently, the dominant model for the formation of enhanced magnetostriction of Fe-Ga alloys is based on the assumption of the presence of microscopic inclusions with a tetragonal L60 structure in the cubic matrix of the alloy. However, no evidence for the presence of this phase in the bulk of the alloys in amounts sufficient to have a noticeable e...

New data on the phase compositions and structural transformations in a number of Fe 81 Ga 19 alloys doped with trace amounts (≤0.2 at %) of rare earth elements are presented. The data were obtained in neutron diffraction experiments performed with high resolution and in a continuous temperature scanning mode under heating to 900°C and subsequent co...

The high-resolution Fourier diffractometer (HRFD) has been in routine operation since 1994 at the long-pulse neutron source, the IBR-2 reactor, in Dubna. Its fast Fourier chopper provides probably the best compromise between very high resolution in reciprocal space (Δd/d ≈ 0.001) and the intensity. For further improving intensity of TOF-diffraction...

Internal friction Thermally activated relaxation Carbon atom diffusivity A B S T R A C T Anelastic relaxation in the temperature range from 0 to 300 • C (0.1-30 Hz) in ternary Fe-26(Al+Ga)-0.1Tb alloys is experimentally studied and analysed with respect to binary Fe 3 Al and Fe 3 Ga intermetallic compounds. The Snoek-type relaxation due to cyclic s...

We report on experimental investigations of a Ni2.36Mn0.64Ga Heusler alloy, which transforms to tetragonal martensite at cooling below Ms ≈ 271°С. The evolution of lattice constants was tracked by in situ neutron diffraction measurements. It was found that the martensite tetragonality c/a gradually decreases during heating from room temperature to...

Anelastic relaxation at elevated temperatures (300-600 • C) in binary and ternary Fe-20(Al+Ga) alloys is experimentally studied and analyzed. Two transient effects due to the irreversible annihilation of quenched vacancies and reversible order (short range D0 3 ↔ disorder A2) transition overlap with thermally activated Zener relaxation due to reori...

The results of the studies of ferroelectric, ferroelastic, and superprotonic crystals, performed by the researchers from the laboratory headed by L.A. Shuvalov at the Institute of Crystallography of the Russian Academy of Sciences and the Laboratory of Neutron Physics of the Joint Institute for Nuclear Research, using methods of neutron diffraction...

A detailed neutron diffraction study of a stoichiometric Fe3Ge alloy with different initial states in a wide temperature range (up to 1000 K) made it possible to accurately reveal the features of magnetic and structural phase transformations in it. The use of complementary x-ray diffraction and analysis of neutron diffraction patterns by the Rietve...

In situ neutron diffraction and internal friction were combined for the comparative analysis of structural and functional properties of Fe-26Al alloy. Three different alloy states were studied: after rapid solidification in graphite mold, after annealing at 900 °С (0.5 h) and water quenching, after annealing at 450 °С (24 h) and slow cooling. Struc...

The evolution in phase composition of as-cast Fe–(31–35) at % Ga alloys during continuous heating up to 850°C with subsequent cooling was studied. Based on the results obtained by neutron diffraction, conclusions were drawn about clearly distinguishable stages of phase formation during heating and cooling of metastable high-gallium alloys. Upon hea...

The crystal structure of the bulk quenched Fe-27Ga alloy has been studied using high resolution neutron and X-ray diffraction to determine the phase distribution over the volume of the material. Neutron diffraction results have shown that the bulk sample consists of completely ordered D03 phase. X-ray diffraction (XRD) with a long acquisition time...

Significant differences between the properties of Fe–Ga alloys (Galfenols) in their metastable and equilibrium states, as well as discrepancies between existing Fe–Ga phase diagrams and for the transition rates for the metastable to equilibrium state have been detected and discussed. In view of both the fundamental understanding and the technologic...

The effect of a high magnetic field (HMF) on phase transition and microstructure formation in Fe-Ga alloys with a Ga concentration of about 25 at.% has been investigated using experimental research and ab initio modeling. We found that the HMF of 25 T significantly accelerates the D03 to L12 transformation in the hyperstoichiometric Fe-27%Ga alloy...

The transition of the A2 phase with random Fe and Cr atoms distribution to the sigma (σ) phase in Fe-46wt.%Cr alloy during isothermal annealing near 655 and 700 ºC is investigated both in the bulk material by in situ neutron diffraction (ND) and on the surface of a sample by X-ray diffraction (XRD) method. Kinetics of the σ-phase formation is quant...

Эволюция структурных фаз и микроструктурного литого состояния составов Fe 100-(x+y) Ga x Al y в диапазоне 17≤(x+y)≤39 at.% изучена в нейтронных дифракционных экспериментах, выполненных с высоким разрешением и в режиме непрерывного сканирования по температуре при нагреве до ~ 900 o С и последующем охлаждении. Установлено, что структуры литых состоян...

Evolution of structural phases and microstructural cast state of Fe 100-(x+y) Ga x Al y compositions in the range of 17≤(x+y)≤39 at.% was studied in neutron diffraction experiments performed with high resolution and in continuous temperature scanning mode when heated to ~ 900 o C and subsequent cooling. It is established that the structures of the...

The thermoelastic martensitic transformation in the polycrystalline Ti29.7Ni50.3Hf10Zr10 alloy was studied using high-resolution and in situ neutron diffraction in the temperature range of 25-250 °C. The thermal expansion tensors of the B19′ martensite and austenite were determined. B19′ martensite is characterized by a strong anisotropy of the the...

The evolution of structural phases and the morphology of the microstructure of several Fe-xAl and Fe-xGa compositions were studied by neutron diffraction with high Δd/d resolution and with high-intensity continuous scanning in a wide temperature range. It was found that the formation of an ordered structure upon a change in the Al or Ga content or...

The evolution of the structural phases of the Fe-38.4 at.%Ga alloy was studied in neutron diffraction experiments performed with high-intensity continuous scanning in a wide temperature range. The as-cast alloy consists of ~70% Fe13Ga9 intermetallic and ~30% bcc-based disordered A2 solid solution (or its partially ordered/short-range ordered B2 var...

The effect of partial substitution of Cu by Cr on the spinodal decomposition of face-centered cubic (f.c.c.) austenite in the as-quenched Mn-10Cu-4Cr alloy is studied after different ageing treatments by small-angle neutron scattering and in situ neutron diffraction. Under the same quenching conditions, additional α-Mn phase with A12 structure in t...

The high-resolution Fourier diffractometer (HRFD) operates at the IBR-2 pulsed reactor, on which the correlation method of data registering has been implemented using a fast Fourier chopper and specialized electronics. A wide-aperture ring back-scattering detector for HRFD has been developed. The detector consists of six Z n S ( A g ) / 6 L i F-sci...

A significant difference in properties and structure of Fe-Ga alloys in their equilibrium and metastable states limits their application. This necessitates an immediate understanding of the importance of cooling rate in the formation of alloy metastable and equilibrium structures. In this paper, we experimentally studied the structure of the Fe-(23...

The atomic structure of the high-temperature β-Fe6Ga5 phase, formed in the Fe-45at.%Ga alloy during rapid cooling from the melt, has been refined by X-ray, neutron diffraction techniques, and density functional theory calculations. The regularities of the phase composition evolution of the quenched Fe-45at.%Ga alloy in the process of continuous slo...

Anelastic effects in Fe-(23-38)Ga binary and ternary alloys doped with rare-earth (RE) elements, RE = Pr, Sm, Tb, Er, and Yb, are studied in a sub-resonance frequency through heating and cooling in the range from 0 to 600 °C. In situ neutron diffraction, vibrating sample magnetometry (VSM), and differential scanning calorimetry (DSC) are used to tr...

Anelasticity of Fe-(16-21)at.% Ga-RE (rare earth RE = La, Tb, Dy, Er, Yb elements) alloys at room and elevated temperatures is studied in a sub-resonance mechanical spectroscopy. Two thermally-activated and two transient effects are recorded in most of the studied alloys. To explain these phenomena, structure and phase transitions in several binary...

By means of powder X-ray and neutron diffraction it is shown that as-cast Fe-38.4 at% Ga alloy consists of Fe13Ga9 intermetallic with a monoclinic Ni2In/NiAs-related structure, which coexists with bcc solid solution. By means of electron backscatter diffraction it is shown that the Fe13Ga9 intermetallic develops with two different but closely relat...

FeGa alloys (Galfenols) are of interest due to their pronounced magnetostriction, whereby the mechanistic understanding is limited. By means of powder X-ray and neutron diffraction it is shown that as-cast Fe-38.4at%Ga alloy consists of Fe13Ga9 intermetallic with a monoclinic Ni2In/NiAs-related structure, which coexists with bcc solid solution. By...

This review article is devoted to studies of the structure and properties of Fe–Ga alloys that serve as functional materials with high magnetostriction. Particular attention is paid to diffraction methods that allow one both to monitor phase transformations in real time and to identify phase structures and microheterogeneities in their structure. B...

Two Fe–Ga alloys with 27 and 29% Ga additionally alloyed with boron (B) were studied using neutron diffraction, scanning electron microscopy with energy dispersive spectroscopy, and magnetostriction measurements. Neutron diffraction experiments demonstrated that the preponderant phase is the cubic Fe3Ga with structure D03. The lattice parameter of...

Single crystal synchrotron diffraction was used for detailed analysis of ordering effects in alloys with a nominal composition of Fe80.5Ga19.5 and Fe73.1Ga26.9. The first composition manifests a disordered average A2 structure with local fluctuations resembling a D03 ordering motif in the lengthscales of ~50 Å. In Fe73.1Ga26.9 alloy ordered over a...

Discovered in the early 2000s, giant magnetostriction prompted many experimental and theoretical studies. However, the physical mechanism underlying this important functional property has not been fully understood, despite 20 years of continuous effort. The models currently under discussion are based on the concept of specifically ordered microscop...

The presentation is about using the neutron diffraction results to built and study the phase transition kinetics from metastable to equilibrium phase in Galfenols

Ferromagnetic high damping (FHA) alloys with a wide temperature range from -150 °C to 300 °C have unique application value in extreme environments. In the present work, the damping behaviors of Fe-21Ga-xLa (x = 0.12 wt.%, 0.24 wt.%, 0.47 wt.%, 1.18 wt.%, and 2.33 wt.%La) alloys have been studied in detail, and a new phenomenological model has been...

The effect of ageing regimes at temperatures in a range from 400 C to 520 C and time for up to 120 h on the spinodal decomposition of austenite in an as-quenched Mne13Cu alloy is investigated using small-angle neutron scattering and in situ neutron diffraction. The as-quenched from 850 C alloy has a 100% antiferromagnetic martensitic structure that...

Thermal expansion of martensite in Ti29.7Ni50.3Hf20 alloy was investigated by in situ neutron diffraction. It is found that the martensite exhibits a strong anisotropy in thermal expansion. The principal crystallographic axes and the coefficients of thermal expansion were determined.

Comparative in situX-ray and neutron diffraction studies of the phase transitions in a high magnetostriction Fe–27Ga alloy sample have been performed, with heating up to 850°C and subsequent cooling to room temperature. Different structural information (phase content, phase-transition temperatures, unit-cell behaviour) is obtained for the bulk samp...

The structure of the Fe-(17.5-19.5)at.%Ga alloys in as-cast and nearly equilibrium states is studied using XRD, ND, and EBSD. In disagreement with the existing phase diagrams, the long-term isothermally annealed at 450-500°C Fe-17.5%Ga alloy has a two-phase structure with two co-existing ferromagnetic phases: bcc-originated A2(D03) as a matrix and...

В обзоре рассмотрены исследования структуры и свойств Fe–Ga-сплавов, являющихся функцио- нальными материалами с высокой магнитострикцией. Особое внимание уделено дифракционным методам, позволяющим как контролировать фазовые превращения в режиме реального времени, так и идентифицировать структуры фаз и микро-неоднородности в их структуре. На основе...

The effect of a high magnetic field (25 T) on the D03 to L12 phase transformation in two Fe-Ga alloys with 24 and 27 at.% Ga during isothermal annealing at 475°C is investigated using neutron diffraction and magnetization measurements techniques. It is proved that annealing in the magnetic field increases the amount of fcc - derived L12 phase in bo...

Sol–gels with different CA/MN ratios, reverse coprecipitation, and solid reaction methods have been applied to carry out MgFe2O4 magnetic material. The influence of synthesis parameters was characterized by using analytical tools, such as high-resolution neutron diffraction, a B-H analyzer, and SEM technique. Using a temperature increasing measurem...

The effect of spinodal decomposition in Mn-19Cu-2Al-4Ni solid solution quenched from 830°C after different ageing regimes is studied. After water quenching, face-centered cubic (f.c.c.) austenite is the only observed phase in the samples at room temperature, whereas, after different ageing regimes, the alloy has a two-phase state: face-centered tet...

Thermoelastic martensitic transformation of Ti29.7Ni50.3Hf20 alloy was studied by high-resolution and in situ real-time neutron diffraction in the temperature range from 25°C to 250°C upon heating and cooling. It was shown that B19′ martensite phase is characterized by strong anisotropy of thermal expansion, lattice parameters of aB19′ and bB19′ in...

A huge difference between the structure and the properties of equilibrium and metastable Fe-Ga alloys along with an uncertain specification for their metastable state lead to an urgent necessity to understand the cooling rate role in the formation of the alloys’ structure. We studied the structure of Fe-27%Ga alloy after cooling, in situ during coo...

In the present study, we have investigated the time and temperature dependence of the transition of as-cast metastable Fe-(9-33at.%)Ga 'Galfenol' alloys to the equilibrium state along with corresponding changes in their functional properties and anelastic effects that accompany these transitions. To characterize such a Time-Temperature Transformati...

Structural features and kinetics of the transition between ordered metastable b.c.c.-derived D03 and equilibrium f.c.c.-derived L12 phases of Fe–xGa alloys (x = 27.2% and 28.0%) have been analyzed by in situ real-time neutron diffraction during isothermal annealing in the temperature range 405–470°C. It has been revealed that the transition proceed...

The microstructural changes, the volume fraction of coexistent phases, heat flow, and internal friction of the Fe–26Mn–4Si alloy are studied during thermal cycling over a range of reversible martensitic transition. The typical microstructure of this alloy at room temperature after various heat treatments is a mixture of γ-austenite (FCC, sp. gr. Fm...

The evolution of the structurally different phases and of the microstructural state of Fe-xAl alloys is studied in neutron diffraction experiments performed in the high resolution and continuous temperature scanning modes. It is found that the D03 phase in a weakly nonequilibrium state of alloys occurring in the doping range from x ≈ 23 to x ≈ 31 a...

Study of structure, phase transitions and anelastic effects in Fe x at.%Ga alloys with X= 25 , 27 and 33

Study of structure, phase transitions and anelastic effects in Fe x at.%Ga alloys with X=25, 27 , 33

Fe-Mn alloy

Euromat 2019, Section A5, 4 September 11:30 am

You can download our paper on editor's site (during 50 days only since 03-09-2019) by clicking on the link: https://authors.elsevier.com/c/1ZgNM3IWkbyXAP Best regards JG Gasser

The structure and microstructure of Fe−xAl−yCr alloys with x=25 and 27 and 0 ≤ y≤15 have been studied by neutron diffraction at several fixed temperatures with high Δd/d resolution and with high-intensity continuous scanning in a wide temperature range. The joint analysis of the obtained data established that the microstructure of these compounds i...

Structural investigations of solid solutions of BaFe12 – xInxO19 barium ferrites partially substituted with indium ions (x = 0.1–1.2) are carried out via the neutron diffraction method. Experimental investigations of ceramic samples are performed at room temperature using a high-resolution neutron diffractometer that allows precise information abou...

The structural, electronic and magnetic properties of Fe100-xGax alloys are studied computationally in the composition range up to x≤ 31.25 at.% and experimentally about 27 at.%. Ga content. Using ab initio calculations, it is shown that as Ga content increases, the lattice parameters are found to increase for all types of structures, as opposed to...

The High Resolution Fourier Diffractometer (HRFD) is a neutron time-of-flight spectrometer with a fast Fourier chopper and a correlation mode of data acquisition designed to study atomic and magnetic structures of crystalline materials with high resolution in reciprocal space. The HRFD was constructed in the early 1990s by a collaboration of JINR (...

A physical model of a high-flux neutron source based on a deep subcritical (keff = 0.96) two-stage booster driven by a proton accelerator with the energy of 600 MeV and beam power of 0.3 MW is proposed. It is shown that the thermal neutron flux density will be comparable to the flux density at the European Spallation Source (ESS) with the proton be...

The investigation of crystal and magnetic structures of BaFe12-xMexO19 (Me=In³⁺ and Ga³⁺; x = 0.1–1.2) solid solutions has been carried out by time-of-flight neutron diffraction method. It was determined the influence of diamagnetic In and Ga ions to unit cell volume of partially substituted barium ferrites. The electric field-induced polarization...

This paper investigates the influence of substitution of 18 at.% of Fe by Co in Fe-27Ga alloy as an effort to improve magneto-mechanical coupling. Study of phase transitions by neutron diffraction reveals that the formation of close packed phases is suppressed in the as-cast Fe-18Co-27Ga alloy. The degree of D03 ordering in the as-cast state for th...

Several aspects of the formation of functional Fe-Ga alloys are considered in this paper: (i) the mechanism of phase transition from a metastable ordered bcc-derivative phase to an equilibrium fcc-derivative ordered phase, (ii) the nature of corresponding anelastic effects, (iii) the usage of isothermal annealing for the formation of an intrinsic c...

The microstructure of nanocrystalline nonstoichiometric niobium carbides NbC 0.77 , NbC 0.84 , NbC 0.96 powders produced by high-energy ball milling has been investigated by time-of-flight (TOF) high resolution neutron diffraction. The diffraction patterns have been collected with the high resolution Fourier diffractometer HRFD by using the TOF mod...