Three-component Alloy Research Articles

Electronic Structure and Magnetic Properties of FeRhSn<sub>1 – <i>x</i></sub><i>Z<sub>x</sub></i> (<i>Z</i> = Ge, Si, Sb): Ab Initio Study

Abstract—Magnetic properties and electronic structure of FeRhSn1 – xZx alloys (x = 0, 0.25, 0.5, 0.75, 1) have been investigated by first-principles methods using the VASP software package. It is shown that for all alloys the γ phase is energetically favorable, except for the FeRhSi alloy, for which the β phase is equilibrium. It is shown that the addition of a fourth element to a three-component alloy leads to a change in the position of the valence zone and conduction zone relative to the Fermi level, which makes it possible to obtain new four-component alloys possessing one hundred percent spin polarization. It is shown that FeRhSn1 – xGex (x = 0, 0.25, 0.5, 0.75, 1), FeRhSn1 – xSix (x = 0, 0.25, 0.5, 0.75) and FeRhSn1 – xSbx (x = 0, 0.25) alloys are half-metallic ferromagnets.

Studies and Considerations on Forty-Three Gold and Silver Nose Ornaments from the Moche Tomb of the Lady of Cao

The authors studied forty-three beautiful nose ornaments from the Moche tomb of the Lady of Cao, located in the north of Peru, which has been dated to be around 300–400 d.C. Of these items, thirty-nine are composed of a sheet of gold alloy joined together in various manners to a silver alloy sheet, which provides a strong contrast at their interface. Two nose ornaments are on gold alloy and two on silver alloy. These nose ornaments were studied using the following methods: (i) Energy-dispersive X-ray fluorescence (EDXRF); (ii) Transmission of monoenergetic X-rays (XRT) and (iii) X-ray Radiography (RAD). The conclusion, deduced from all applied methods, was that two sheets of gold and silver alloys were joined together with various methods, including gluing, mechanically joining, soldering, smelting with the aid of heating or using mercury to create an amalgam. It cannot be excluded that a few areas, visibly appearing as silver, were obtained by depletion silvering from the base Au-Cu-Ag alloy. By analyzing a fragment from the silver area of a nose ornament and by studying a few other nose ornaments from the tomb of the Lady of Cao in situ, G. Ingo and co-workers concluded that a unique sheet of three-component alloy (Ag-Cu-Au), whichemployed and transformed the surface of the objects to appear to be gold and silver by depletion gilding and silvering.

Non-Equilibrium Shells around Precipitates During the Decomposition of a Three-Component Alloy

The kinetic theory of diffusion over vacancies is used to obtain expressions for the fluxes of atoms in a three-component alloy. This hole gas approach allows us to express kinetic coefficients in terms of the coefficients of diffusion of labeled atoms from microscopic considerations. The conditions for the formation of nonequilibrium impurity shells are revealed by studying the kinetics of decomposition using these expressions. These shells can considerably inhibit the growth of precipitates and change the properties of the alloy.

Non-Equilibrium Shells around Precipitates During the Decomposition of a Three-Component Alloy

Non-Equilibrium Shells around Precipitates During the Decomposition of a Three-Component Alloy

FORMATION OF COMPOSITE COATINGS WITH MAGNETIC PROPERTIES IN AN ELECTROMAGNETIC FIELD

The article presents and analyzes the results of the study of the influence of a constant magnetic field on the electrodeposition processes of the ferrum family metals and their alloys. The studies performed indicate the effect of accelerating deposition, improving the surface morphology and hardness of the obtained coatings. Composite coatings applied under the influence of a constant magnetic field can have higher corrosion resistance, improved photocatalytic and magnetic properties than those obtained without it. It has been established that the presence of a constant magnetic field changes the chemical composition of the studied material. There is an increase in the ferromagnetic and a decrease in the diamagnetic component. To assess the magnetic properties, samples of Fe-Co-W and Fe-Co-Mo coatings deposited by unipolar pulsed current at different electrolysis durations were selected, which is due to the difference in the thickness and distribution of the components. The results obtained suggest that in the nonequilibrium process of electrodeposition in three-component alloys, clusters with a short-range order characteristic of a number of intermetallic nonmagnetic compounds are formed, which leads to a decrease in the saturation magnetization of the alloy. The Fe-Co-W coatings are characterized by higher values of the coercive force compared to amorphous alloys, in which the elements P, B, Si act as a non-magnetic component. Probably, for the Fe-Co-W alloy, large clusters with a compositional order similar to the arrangement of atoms in the paramagnetic intermetallic phase with tungsten, along with surface roughness and free volume, play a significant role in magnetization reversal. The results obtained make it possible to classify the obtained Fe-Co-W galvanic alloys as magnetically hard, and Fe-Co-Mo as magnetically soft materials, which, in combination with high microhardness, opens up prospects for the use of such systems in the production of magnetic elements for recording and reproducing information and microelectromechanical systems respectively. With properly designed field structures, new magnetic nanostructures and a new level of control over industrial catalytic and electroplating processes can be created.

Synthesis of Tree-Component Cobalt-Based Alloy by Selective Laser Melting

The paper presents studies aimed at producing a three-component alloy from the powders of cobalt, chromium and molybdenum (66 wt % Co, 28 wt % Cr, 6 wt % Mo), with a stable phase structure by selective laser melting. At the beginning of the work, the initial powders were graded on sieves with mesh sizes of 20-70 µm. The powder mixtures were obtained by mechanical mixing of various fraction powders and mechanical alloying in a planetary ball mill. The samples were produced using the VARISCAF-100MVS selective laser melting unit. The melting process of powder materials was completed in a chamber filled with inert gas argon after preliminary vacuum degassing. The microhardness analysis of the samples before and after the thermal treatment was completed. The results of phase composition studies, X-ray diffraction analysis, scanning electron microscopy are presented. Examination of the X-ray profiles of the samples proves that the obtained alloy mainly contains the epsilon-phase which improves the hardness and the wear resistance of the product.

Основы построения струйно-капельных оптических систем измерений напряженности электрического поля. Часть 2

In this part of the article, the discussion of the construction of jet-drop optical measuring systems (JDOMS) for monitoring the electric field strength continues. The possibilities of increasing the resolution are considered. A variant of the interference JDOMS using triangulation stroboscopic measurements of displacements of charged moving droplets using a pulsed acousto-optic interferometer of transverse displacements of a laser beam is presented. The possibilities of increasing the charge/mass ratio of charged droplets, the features of using liquid metals and their two- and three-component alloys as liquids, the use of inhomogeneous droplets in the form of hollow, hollow microspheres similar to soap bubbles and/or based on a porous (dispersed) material are discussed.

Two- and three-component alloys nanowires: correlation of structural and magnetic properties

Several types of nanowires (NWs) made of alloys of various compositions obtained by the method of matrix synthesis based on track membranes have been studied. Electrolytes were selected to obtain NWs of the desired composition. The control of electrodeposition by chronoamperograms made it possible to systematically change the geometric parameters and morphology. The topographies of the resulting NW arrays and their elemental composition were studied using electron microscopy with an X-ray spectral analyzer. The magnetic properties of the samples were studied on a vibrating magnetometer. The structures of binary alloys were studied: for NWs of FeCo alloys, the dependence of the coercive force on the composition was studied. The obtained dependence has two maxima --- at an equiatomic composition and at a cobalt content of about 90%. For Fe0.3Co0.7 NWs, a sharp increase in the coercive force with decreasing diameter is shown. It is assumed that this effect is due to the formation of single-domain crystallites, the processes of magnetization reversal of which are associated with a uniform rotation of the magnetization. For NWs made of FeNi alloys, the influence of the aspect ratio on the coercive force has been proved. Ternary alloys of the FeCoCu system have been studied: it has been shown that the addition of copper significantly increases the coercive force, which reaches a maximum at a copper content of about 5%. The obtained X-ray data suggest that the effect of an increase in the coercive force is associated with the formation of fine-grained inclusions based on copper, which lead to effective deceleration of the domain walls. The data obtained expand the range of possibilities for controlling the magnetic properties of NW arrays obtained by the method of matrix synthesis. Keywords: nanowires, matrix synthesis, microscopy, elemental analysis, magnetic properties, coercive force. Keywords: nanowires, matrix synthesis, microscopy, elemental analysis, magnetic properties, coercive force.

Effect of Workpiece Atom Diffusion Into CBN Tool on Its Mechanical Properties in Cutting Ni–Fe–Cr Alloy Based on Molecular Dynamics Simulation

CBN (Cubic Boron Nitride) tool is suitable for precision machining of nickel-based alloy due to its high hardness and chemical inert. Nickel-based alloys are difficult-to-cut material. When high-speed cutting nickel-based alloys with CBN tool, the temperature at tool-workpiece interface is very high. The atoms in workpiece material diffuse into the tool surface and change the performance of cutting tool, resulting in diffusion wear. Inconel 718, which is one kind of widely used nickel-based alloy, is mainly composed of nickel (Ni), iron (Fe) and chromium (Cr). In this paper, the cutting model which describes the single crystal CBN tool cutting Ni–Fe–Cr three-component alloy, and the compression and impact model of CBN tool crystal are established by using molecular dynamics (MD) method to study the diffusion of Ni, Fe and Cr atoms into CBN tool and the effects of diffusion on the properties of CBN crystal tool. The results show that the diffusion of Ni, Fe and Cr atoms into CBN tool decreases the compressive strength and impact toughness of CBN crystals and the effects degree of atom diffusion on the properties of CBN crystals are different.

КЕРАМИЧЕСКИЕ ЛИТЕЙНЫЕ ФОРМЫ ИЗ ПАМЯТНИКА КРУГЛАЯ ДОЛИНА В ПРИМОРЬЕ: ОПЫТ МЕЖДИСЦИПЛИНАРНОГО ИССЛЕДОВАНИЯ

The article presents an interdisciplinary study of casting molds as one of the kinds of old technical (“metalworking”) ceramics. The material of the study is ceramic molds (47 whole and fragmented samples) unearthed at the Kruglaya Dolina settlement in the central Primorye region. The molds and other objects of technical ceramics (crucibles, nozzle) were found in destroyed, non-stratified cultural deposits and connected with the remains of bronze-casting workshops complex which was dated supposedly to the Bohai state period, 698-926. The study aimed (1) to examine the morphological and technological characteristics of the molds, and (2) to detect traces of alloys at the working surfaces of the molds. The study employed methods of binocular microscopy and laboratory refiring testing for (1), and scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), portable X-Ray fluorescence spectroscopy (pXRF) for (2). The analyzed ceramic molds were intended for the casting of semi-spherical buttons, several kinds of pendants, rosette-shaped openwork ornaments. Original bronze items which could be cast in these molds were not found at Kruglaya Dolina. According to the data on the morphological variability of the molds together with the results of the examination of the ceramic pastes technology, one can suppose that the casting molds were produced by different craftsmen or different workshops. SEM-EDS and pXRF analyses detected the traces of bronze alloys at 15 mold samples with carbonized working surfaces. Chemical elements - metals - lead (Pb), tin (Sn), and copper (Cu) are traced in various combinations at various samples. In some cases together with metals arsenic (As) is detected. The interpretation of these results follows methodological recommendations based on the published data of experimental research. The presence of certain elements can be stated, and their relative concentrations in the spectrum composition can be evaluated. However, it is necessary to take into account that the amounts of certain elements in the spectrum do not correspond to their amounts in the original alloy composition. Therefore, qualitative characteristics of the alloys can be determined, but not quantitative ones. According to the results, the three-component alloys containing copper, tin, and lead are recognized certainly. The tin-copper non-lead alloy and the “pure copper” alloy are supposed in some cases. Previous investigations on the old bronzes chemical compositions in southern Russian Far East revealed that three-component alloys (lead-tin-copper) containing arsenic had been used widely during the Bohai state period. Tin-copper and “pure copper” alloys were known at that time as well. It seems to be likely that the casting molds from the Kruglaya Dolina site are dated to the Bohai state period. Further researches of this site's bronze-casting workshops complex remains will focus on other categories of technical ceramics.

Formation of Structural-Phase State in a Cobalt-Chromium-Molybdenum Alloy by Selective Laser Melting

Heat resistant cobalt-based alloys have found a specific niche in the present-day mechanical engineering due to their unique properties. To begin with, cobalt-based alloys are used as corrosion, heat and wear resistant materials intended for aggressive environments and operation at extreme temperatures, e.g. blades, nozzles, swirlers, rings and other elements of turbines and internal combustion engines. Traditional molding methods applied in the mechanical engineering fail to provide necessary operational and technological characteristics of aforementioned machine parts. Owing to selective laser melting it is possible to reduce a production time and manufacturing costs for machine elements with a complex physical configuration and generate an alloy with an extraordinary structure, which is not found in traditionally combined compounds. A structure of cobalt exists in two crystal modifications: a hexagonal close-packed epsilon phase, a low-temperature phase and a face-centered cubic lattice gamma phase, a high-temperature phase. The alloy hardness is directly related to an amount of a low-temperature phase. The laser melting shortens a laser beam impact time on a powder composition due to a higher power and laser travelling speed. A high value of heat conductivity seems to be the reason for rapid solidification and cooling, which, in their turn, increase a percent of an alpha-martensite phase in an alloy and improve the hardness and wear resistance of machine parts. The reported paper summarizes studies aimed at the development of a stable phase structure three-component alloy (Сo-66 mass % Cr-6 mass % Mo) based on the cobalt-chromium-molybdenum system and mixed up via selective laser melting.

НОВЫЕ ДАННЫЕ ПО СОСТАВУ ЦВЕТНОГО МЕТАЛЛА ИЗ МОГИЛЬНИКОВ ЭПОХИ БРОНЗЫ ЮЖНОГО УРАЛА (ТАВЛЫКАЕВО I-II, СТАРЫЕ ЯБАЛАКЛЫ)

The article presents the results of elemental analysis of the composition of metal objects obtained from the burial grounds dating back to the Srubna culture of the South Urals. The data were received through analyzing the most common category of jewelry - bronze bracelets. The prevailing shapes are open grooved bracelets with rounded ends, as well as bracelets made of rods and twisted wires with semicircular and triangular sections. The main purpose of this work is to give a general description of the oldest metal composition and compare the series of findings from the Cis-Urals and Trans-Urals. The first stage of the work involved examination of 10 samples of the Trans-Ural group of objects from Tavlykaevo 1 and 2 burials and 7 decorations from the Srubna burials of the Staro-Yabalakly necropolis (Cis-Urals). The principal metallurgical group includes tin bronzes with three-component alloys of copper, tin and lead or copper, tin and antimony. In terms of its composition, the series of findings under study was quite clearly differentiated. In the Trans-Ural assemblages, objects with addition of lead were primarily found in the burials of Tavlykaevo I burial ground, while in Tavlykaevo 2 burial ground, copper-tin alloys with antimony inclusions prevailed. In the Staro-Yabalakly necropolis, a single object might contain an admixture of antimony and lead. Depending on the elemental composition of non-ferrous metals in various categories of objects, it is hypothetically possible to reconstruct the directions of metal supply to the South Urals and characterize the local features of the metallurgy development in this region in the Bronze Age.

Interpretation of Mössbauer Spectra for Determining Short-Range Order Parameters in Three-Component Alloys

The studying the short-range order (SRO) in a three-component alloy on the basis of interpreting Mossbauer spectra is discussed. We suggested a description of a homogeneous SRO in a three-component alloy using the formalism of Flinn’s occupation numbers and the expansion of probabilities of cluster patterns in terms of correlation moments, quantitatively describing SRO. The method is further refined by minimizing the functional, constructed of differences between the measured and calculated intensities, with determination of Mossbauer parameters and correlation moments.

Parameters of Mechanical Properties and Resistance of Intermetallic Compounds to Martensite Transformations

The paper analyzes Poisson’s ratios μ0=μ100,001=-s12/s11 and elastic anisotropy factor A'=s/s11 (s=s11-s12-s44/2) for single crystal materials of binary and three-component TiNi-TiFe alloys with gradually deteriorating resistance first to one B2-R and further to two martensite transformations B2-R-B19'. The study discusses a ratio H/E of TiNi-TiFe alloys both subject and not exposed to martensite transformations. Surprisingly, this ratio exceeds 0.035 for alloys with martensite transformations, being far higher than in the majority of metals and alloys.

Metastable Dispersed States Arising upon Three-Component Alloy Decomposition

Metastable Dispersed States Arising upon Three-Component Alloy Decomposition

Физико-химические свойства тройных металлических систем Fe-Si-Nb и Fe-Al-Nb

The Russian Federation has a sufficient number of promising deposits of niobium raw materials which can satisfy the niobium and tantalum demands of Russian metallurgical enterprises for many decades. Ferroalloy technologists are faced with the difficult tasks of developing from various types of ore raw materials not only effective processes for its processing but also new acceptable rational compositions of niobium-containing ferroalloys. The chemical composition of niobium ferroalloy should, on the one hand, correspond to the product obtained by benefication (concentrate) and, on the other hand, satisfy the requirements of steelmakers for ferroalloys intended for microalloying niobium steel. To develop rational compositions of new niobium-containing ferroalloys in this work the physicochemical characteristics (which include crystallization temperature and density) of alloys containing 10-50% Nb, 10-40% Si, and 5-30% Al were studied. Two-component Fe-Nb metal alloys have a rational crystallization onset temperature (<1400 °С) only when the niobium content is not more than 10%. To achieve rational crystallization onset temperatures it is necessary to use complex alloys with silicon and aluminum. Studies have shown that a decrease in the crystallization onset temperature of complex niobium alloys occurs when the niobium content decreases with an increase in the concentration of silicon or aluminum. Three-component alloys Fe-Si-Nb and Fe-Al-Nb with a content of 15-20% Nb, 32-40 Si% or 12-30% Al belong to the category of low-melting ferroalloys. To achieve rational density values light metals such as silicon or aluminum must be introduced into a two-component system. The studied three-component alloys with a content of 25-40% Si or 15-30% Al have rational density values both from the point of view of their production and application to the processing of steel melt. The best physicochemical characteristics providing high service properties are possessed by complex niobium (15-20% Nb) FeNbSi alloys with 32-40% Si and FeNbAl with 15-30% Al which are recommended for widespread use in ladle microalloying of steels.

Monte Carlo Simulation of Diffusion Processes in Three-Component Alloys

The methods of molecular dynamics applied to a representative volume of a substance make it possible to calculate atomic trajectories within the time intervals on the order of 1 ns, which ensures an investigation of such slow processes as diffusion. This problem can be solved using the Monte Carlo method successfully applied to investigation of such diffusion-controlled processes as order – disorder transitions in the alloys or diffusion welding of heterogeneous metals through a backing plate. The majority of studies have been made for binary alloys, while the alloys in practical use contain a larger number of components. A theoretical model is presented, which allows investigating diffusion processes in three-component alloys via the vacancy mechanism in a solid-sphere approximation. A relation is derived for calculating the potential energy of an alloy, which is specified for the case of a completely disordered alloy. The difference between these energies is expressed via the ordering energies and order parameter. The proposed model is applicable to crystal lattices of any dimensionality. An example of its use for a three-component alloy of the A2BC stoichiometry is given, whose atoms occupy the sites of a two-dimensional square lattice is given.

Interdiffusion Analysis in Ternary Systems to Process Composition Profiles and Obtain Constant Interdiffusion Coefficients Using One Compact Diffusion Couple

The interdiffusion process in a three-component alloy system has been studied by means of numerical analysis. The composition profiles for a ternary system were generated making use of the closed-form solution with a constant interdiffusion matrix with the accompanying analysis of the diffusion paths. Two methods [the Fitting Method and the modified square root diffusivity (MSQRD) method] have been considered to investigate the inverse interdiffusion problem for application to a single interdiffusion couple measurement. The Fitting Method simultaneously fits the required functional form into the data obtained for two composition profiles. Such fitted parameters are used to determine the constant interdiffusion matrix. The MSQRD method has been applied to the generated composition profiles and performs very well for all the cases considered. It was found that the errors of the MSQRD method are, in general, lower than in the use of the Fitting Method even without imposing artificial noise on the composition profiles to mimic the experimental data. In addition, it has been shown that the back-tests of the composition profiles must not be used as the only proof of the reliability of the methods used.

Моделирование методом Монте-Карло процессов диффузии в трехкомпонентных сплавах

Моделирование методом Монте-Карло процессов диффузии в трехкомпонентных сплавах

Метастабильные дисперсные состояния, возникающие при распаде трехкомпонентного сплава

Abstract In this paper, we consider the conditions for inhibiting the growth of precipitates from a metastable supersaturated solid solution and at the evaporation-condensation stage during spinodal decomposition of a three-component alloy. The formation of a “locking” shell around precipitates was shown to be an effective mechanism for inhibiting decomposition, provided that the solubility or diffusion coefficients of the alloy components are reduced in the shell. The thermodynamic and kinetic conditions for the appearance of such shells are formulated. The features of decomposition inhibition mechanisms in specific alloys are discussed.