Igor S. Golovin

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• Prof. Dr. (Habil.)
• Professor at National University of Science and Technology

Неупругость является неотъемлемой частью проявления физических и механических свойств металлов и сплавов. Механическая спектроскопия открывает новые возможности в понимании и анализе процессов их структурообразования. В монографии рассмотрены основы теории и примеры практического использования неупругих явлений в твердых телах, связанных с анализом...

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...

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...

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...

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...

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...

Stress-assisted atomic diffusion behavior in NiTiHf shape memory alloys was investigated by measuring the internal friction at temperature range of 300-1070 K. A thermally activated internal friction peak was recorded in the B2-ordered phase in the temperature range of about 850-950 K (at 1 Hz, depending on alloy composition), with activation energ...

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...

Magnetron sputtering with a chromium-containing Fe-19at.%Cr alloy is used to improve the corrosion resistance of Fe-20at.%Ga alloy. The structure of the 2 μm coated layer and distribution of the elements (Fe, Cr, and Ga) are investigated. The bcc phase (A2 structure) is observed in the sputtered sample by XRD analysis. The corrosion resistance in 3...

Magnesium-based materials not only exhibit desirable characteristics such as low density and high specific strength, but also possess exceptional functional properties, including high damping capacity, high thermal conductivity, high electromagnetic interference shielding capacity, flame retardancy, and dissolvability. However, achieving a balance...

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...

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...

Ni50Ti30Hf20 high temperature shape memory alloy was aged at 550 °C for 10 h and 450 °C for 50 h which corresponds to the peak hardening state with equal gain in strength caused by different size/volume fraction ratio of nano-precipitation of H-phase. In order to determine the effect of such structures on the martensitic transformation, thermal cyc...

The analysis of structure-induced anelasticity in the wrought AA5051 alloy subjected to two different treatment schemes was performed: the simple compression between flat dies and the compression combined with torsion for additional shear deformation. Aanelasticity caused by structural transitions were studied using temperature-, time-, and amplitu...

Proceedings of 19th International Conference on Internal Friction and Mechanical Spectroscopy 2022. Eds. Igor S. Golovin and Francesco Cordero.

Fe-Ga alloys (GalFeNOLs) are the focus of attention due to their enhanced magneto-elastic properties, namely, magnetostriction in low saturation magnetic fields. In the last several years, special attention has been paid to the anelastic properties of these alloys. In this review, we collected and analyzed the frequency-, amplitude-, and temperatur...

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...

The analysis of the structure of the AA5051 alloy subjected to different schemes of the plastic deformation was performed. Three types of the sample were prepared from a hot-pressed rod of the wrought AA5051 alloy. Two of them were subjected to the plastic deformation at room temperature - the compression between flat dies and the compression with...

Magnetostriction and damping of forced vibrations in Fe-Mo single and polycrystal alloys is studied and analyzed with respect to existing approaches and experimental data. Our data suggest that a more complex dependence (compared with linear dependence predicted by Smith and Birchak) between damping capacity and magnitostriction takes place for thi...

Al-Mg alloys (AA5083-type) are widely used for superplastic forming. Limited grain boundary sliding as compared to other superplastic alloys limits the formability of Al-Mg based alloys. Grain boundary sliding intensity depends on the grain size, grain boundaries structure, and chemical composition of alloys. To improve superplastic properties of A...

Large magneto-mechanical properties are attained for Fe79.9Al20-xTb0.1Gax alloys prepared by directional solidification (DS). We obtain high delta E (ΔE) effect of 9.1-13.4% and magneto-mechanical coefficient (K) of 29.7-49.5% with good controllability of E by H and high sensitivity of E at low H, beneficial for the practical applications. The enha...

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...

DMA is a useful tool to study visco-elastic polymers but it is not always very precise for metallic materials, in particular for measuring absolute values of Elastic modulus. Some examples of DMA tests of different metallic alloys are collected here.

As the Conference is run in hybrid mode, all the participants have to pay a conference fee for online participation. Those, who come in person and wish to participate to excursions or conference dinner have to pay them on site.

The magnetostriction, damping capacity and mechanical properties of a Fe-Cr-Mo-Al alloy are studied and compared with binary Fe-Cr and Fe-Al alloys. Synchronous change in magnetostriction and damping in Fe-16Cr-0.6Mo-0.6Al alloy: the maximum magnetostriction strain and damping capacity are obtained after annealing at 900°C followed by air cooling....

Deformation of a Cu-Pd-P amorphous alloy is studied under periodical mechanical load (stress/unload cycle with 0.3 Hz or 3 Hz frequency) on heating at the constant rate of 5 K/min. We show that deformation of the material is interpolated with a hyperbolic function of time or temperature. As predicted non-isothermal cyclic deformation takes place wi...

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...

Enhancement of the magneto-mechanical properties in directional solidified Fe80Al20 alloys by doping Tb is demonstrated. The ΔE effect of 9.1%, large magnetostriction of 144 ppm, magnetostriction sensitivity of 0.28 ppm/Oe, ΔG effect of 5.4%, and magneto-mechanical coupling of 29.74% reached for Fe79.9Al20Tb0.1 alloy are beneficial for applications...

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...

Modelling of the deformation process of Al85Y8Ni5Co2 amorphous alloys was carried out under simultaneous application of cyclic mechanical load (at 0.3 or 3 Hz frequencies) and continuously increasing temperature (heating rate 5 K/min). It is shown that deformation of the amorphous specimens occurs by the hyperbolic temporal dependence. It is analyt...

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...

19th International Conference on Internal Friction and Mechanical Spectroscopy PREFACE

The Special Issue ICIFMS-19 in the Journal of Alloys and Compounds was born as a collection of selected contributions to be presented at the 19th International Conference on Internal Friction and Mechanical Spectroscopy conference (http://icifms19.ru/), that should have taken place in Moscow during 29.06-03.07.2020, but has been postponed due to th...

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...

The mechanical properties of Zr-bearing aluminum-based alloys directly depend on heat treatment that yields precipitation of the L12-Al3Zr phase. Choosing an effective treatment leads to high density of nanoscale dispersoids and improves the strengthening effect of zirconium. The precipitation effect, recrystallization behavior, internal friction,...

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...

The problem of estimation of the tracer diffusion coefficients is solved by utilizing a novel tracer-interdiffusion couple technique even in the absence suitable radioisotope of one of the components and absence of reliable thermodynamic parameters. This is demonstrated by generating reliable and reproducible mobility data in the alloys of the Fe-G...

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...

The microstructures and phase compositions of Fe–Ga alloys with Ga contents from 15 to 45 at.% are investigated in detail applying prolonged annealing treatments at temperatures below 600 °C. X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating-sample magnetometry (VSM), and Electron backscatter diffraction (EBSD) coupled with...

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...

19th International Conference on Internal Friction and Mechanical Spectroscopy 29.06-03.07.2020, Moscow, Russia postoned to 28.06-02.07.2021, Moscow, Russia

In view of the progression of the COVID-19 pandemic, the ICIFMS-19 must be postponed. It is too early to predict a reliable date and the Local Organizing Committee is considering November 2020 or June 2021 as possible dates for the Сonference. The decision will be announced in August 2020 and your opinions will be taken into account. Please, foll...

We cannot exclude that the present dates of the meeting will have to be postponed to a later date this autumn.

The current paper deals with the influence of Tb doping on magnetic and magnetostrictive properties of Fe-19Ga-xTb (x up to 0.37 at.%) and Fe-27.4Ga-xTb (x up to 0.5 at.%) alloys at room temperature by vibrating sample magnetometry and strain gauge methods. The magnetocrystalline anisotropy constant and the magnetic permeability are improved in Fe1...

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...

Good mechanical properties and relatively low switching magnetic field make Fe-Ga alloys very useful magnetostrictive material for wide range of practical applications. Doping with rare-earth elements (such as Tb) can significantly increase magnetostriction, because Tb rearranges vacancy structure during phase transitions in Fe-27Ga alloys. It was...

The microstructure and, in particular, the modified-D03 (m-D03) nanoinclusions play an important role in the magnetostriction of binary Fe83Ga17 and Fe83Ga17Tb0.2 alloys. However, the structure evolution of nanoinclusions as well as their influence on the magnetostriction with the Ga contents larger that 19 at. % remain unclear. Here, the microstru...