The results of studying the possibility of fabricating the Pr2Fe14B/α-Fe composite materials by oxidation of the Pr–Fe–B alloy in a fluidized-bed jet mill are presented. It is shown that the use of the standard powder metallurgy technology supplemented by oxidation of the Pr–Fe–B alloy in a fluidized-bed jet mill for rare-earth magnetically hard materials (MHMs) makes it possible to fabricate Pr2Fe14B/α-Fe

Abstract Composite materials (CMs) exhibit high hardness, mechanical strength, and wear resistance, but their processing properties are limited. The most popular reinforcements for composites are carbides, nitrides, and oxides. Amorphous metallic materials are an alternative reinforced component. Metallic glass can provide increased properties due to higher interphase strength between their particles

Abstract The rapid development of the alumina industry in China has led to the depletion of high-quality bauxite resources. The proposed calcification-carbonation method (CCM) can convert the middle silicon of bauxite into CaO · SiO2 and CaCO3, thus enabling clean and efficient utilization of low-grade resources. Since kaolinite is the main silicon-bearing mineral in low-grade bauxite, the transformation

Abstract Single- and double-layer coatings on 40Cr steel substrates have been obtained by electrospark alloying (ESA) and a combination of ESA technology and pulsed cathodic arc evaporation (PCAE) using TiCNiCr and TiCNiCr–Dy2O3 electrodes. The electrodes are obtained by powder metallurgy. The structure and elemental and phase composition of the electrodes and coatings are studied using scanning electron

Electron beam melting (EBM) is a powder bed fusion additive manufacturing (AM) technique that produces three-dimensional (3D) parts by fusing metallic powders with a high-energy electron beam. Powder has been major issue for the properties of the final parts. Hence, establishing the effect of powder properties on the final product properties is important for producing parts of quality. In this study

Abstract Different stresses can occur in the carbon cathodes due to melting and penetration of sodium during aluminum electrolysis. Under high temperatures and elevated stress, carbon blocks experience primary creep, which can be extended to the secondary and tertiary creep stages. It is quite necessary to characterize the creep behavior of carbon cathodes. Therefore, uniaxial compressive creep testing

Rolling bearing rings comprise a large reserve for expanding powder metallurgy production. This reserve is being incompletely implemented. The hot forging of porous preforms makes it possible to produce high-density materials for the fabrication heavy loaded wares, in particular, rolling bearing rings. The problem of fabricating hot-forged bearing rings is associated with the presence of a large amount

This paper presents the results of obtaining and studying the structure and properties of cermets based on powders of aluminum oxide and nickel–aluminum alloy doped with 0.1 wt % of aluminum–magnesium spinel nanoparticles sintered by the electrospark method on a FCT-HP D 25 unit in argon at t = 1470°C for 30 min. The results of the NiAl–65Al2O3 charge TG and DSC analysis at up to 1300°C are presented

Abstract The composition and crystal structure of compounds produced by self-propagating high-temperature synthesis (SHS) from the 5Ta–2Ni–3Al (at %) powder mixture followed by vacuum remelting at 3000°C are studied. The SHS product contains the following phases: TaNiAl (Laves τ1 phase), NiAl, Ni2Al3, and Ta. Its microstructure includes Ta85Ni7Al8, Ta52Ni20Al28, and Ta53Ni25Al22 ternary phases according

Abstract The effect of the structure of the initial charge density in liquid and solid states, as well as on the temperature–time parameters of the process of solidification of the AK6M2 alloy (Al–6% Si–2% Cu), is shown. To obtain a coarse-crystal charge (C charge), part of the melt is crystallized in ceramic forms in a sand backfill with a cooling rate of ~0.5–1.0°C/s. The fine-crystal charge (F charge)

Abstract The aim of this study is to investigate the AZ31 alloy powder production and characterization processes experimentally using the gas atomization method. For this purpose, firstly, the design and production of gas atomization units were done at Karabük University Faculty of Technology Department of Manufacturing Engineering. In this gas atomization unit, the manufacturability of AZ31 powder

Abstract Tajikistan has a large volume of gold-containing dumps, which on conversion to gold equals ~18 t. These dumps are products of amalgamation and cyanidation processes, resulting from treating the ores from Tarorskoe, one of the largest deposits in Tajikistan, and from a few other nearby deposits: Dzhilau, Khirskhon, and Olimpiiskoe. The mineralogical composition of the dumps is represented primarily

In this paper, a new type of copper (Cu) matrix graphite composite was successfully prepared, which was reinforced with titanium nitride particles (TNPs) using powder metallurgy. These composites contained 2 wt % graphite as the lubricating phase and 1, 3, 5, 10, and 15 wt % TNPs as the reinforcing phase. The effects of different TNP contents on composite properties and the composites' wear mechanism

Abstract Nanostructured mechanical composites of immiscible metals Cu, Cr, and 5–70 wt % W; nanostructured consolidated materials based on them; and Cu/Cu–Cr–W nanostructured gradient material with various W contents are fabricated in this work by combining short-term (up to 150 min) high-energy ball milling (HEBM) and spark plasma sintering (SPS). To fabricate Cu–Cr–W mechanical composites, HEBM of

Abstract Electron probe microanalysis (EPMA) has been used to obtain concentration curves and calculate the bulk diffusion coefficients of Sn in solid solutions of the copper–tin system in a tin concentration range of less than 13.9% weight (7.96 at %) and temperature range from 500 to 650°C. Diffusion couples are made from pure Cu (99.995%) and a two-component alloy of Cu with chemically pure Sn by

Single β-type Mg–12Li and Mg–12Li–1Al (wt %) alloy sheets were prepared by casting, followed by cold rolling. Microstructure and texture analysis were carried out on the alloy samples using optical microscopy, scanning electron microscope, X-ray diffractometry, and microhardness testing. The results indicated that cold-rolled alloys exhibited elongated grains in rolling direction with many slip lines

It is known that materials based on MAX phases possess a large potential for use in aerospace, automobile, and industrial spheres because they have a unique combination of features of both metals and ceramics with high mechanical, chemical, thermal, and electrical properties. In this work, the experimental results of fabricating cast materials in the Cr–Al–C system with different ratios between the

The possibility of performing SHS for the composition (wt %) 81.5Ti + 18.5B in air with subsequent compaction of combustion products in an open steel mold with the walls limiting their radial flow under severe heat dissipation conditions without using an intermediate loose heat insulator is investigated. The preparation modes of reaction powder mixtures to the synthesis is optimized. Process characteristics

Abstract This work is devoted to the finite-element modeling of the deformation mode of a small-diameter rod billet during pressure hot treatment in the combination of radial shear rolling (RSR) and rotary forging (RF). Modeling is performed using a rheological model of the Ti–6Al–4V titanium alloy using the QForm VX program. The combination of RSR for one passage of a billet 15 mm in diameter to a

Abstract The conditions of the formation of stable and metastable aluminides Aln(Zr1 – xNbx) formed during the crystallization of superheated melts of the Al‒Zr‒Nb system are considered. Upon a close zirconium content in the alloys of 0.23–0.25 at %, the niobium content varies from 0.05 to 0.21 at %. Alloys are prepared in a resistance furnace at a temperature of 1230°C in an argon atmosphere in graphite

In recent decades, jewelry manufacturers have started using nonprecious alloys to decrease production costs. A large number of customers, however, have an allergic (sensitizing) body reaction to jewelries made of such materials. The application of nonsensitizing coatings can decrease the negative influence of the jewelry material on the human organism. One material biologically inert towards human

The process of porous iron powder spheroidization with a particle size from 45 to 85 μm is investigated in the microwave discharge and joint microwave and DC discharge modes in nitrogen and helium plasma. The powder was prepared by air spraying and annealed in hydrogen. Spraying in plasma results in hollow spheroidized particles with a wall thickness from 1 to 10 μm. The fraction of spheroidized powder

Abstract Based on the studies of its structure, as well as technological and mechanical properties, the composition and application prospects are substantiated for a high-strength aluminum Al–Zn–Mg–Ca–Fe casting alloy with no heat treatment. As the subjects of study, we have obtained alloys based on a composition of Al–5.5% Zn–1.5% Mg (wt %) jointly and separately alloyed with 0.5–1.0% Ca, and 0.5%

Abstract In this work, an attempt is made to identify the optimized parameter combination for improved creep and corrosion properties of AA5083-H111 alloy weldments processed by Spin-Arc gas metal arc welding (SA-GMAW) process. For this, the Artificial Neural Network (ANN) coupled with Genetic Algorithm (GA) was used as a statistical tool. Experiments were conducted by considering the input parameters

TiC + Al binder metal-matrix composites are fabricated by self-propagating high-temperature synthesis (SHS) in reaction power mixtures of titanium, carbon (ash), and aluminum. It is established that stable combustion in a steady wave mode is possible with a content up to 50 wt % aluminum powder in a reaction mixture. Crushing of synthesized loose cakes and subsequent sieve scattering gave composite

The results of studying the corrosion resistance of the powder of the TiB2–TiN eutectic alloy in a medium of HCl and HNO3 mineral acids are presented. The experiments are performed for samples synthesized in the combustion mode and then powdered in an agate mortar. The particle morphology, size distribution, and specific surface are determined for fabricated powders. The concentrations of acids are

Abstract Overcooling of gallium–tin alloys under normal conditions has been studied by thermal analysis. The following samples have been analyzed: Ga (I); two hypoeutectic alloys: 95% Ga + 5% Sn (II), 90% Ga + 10% Sn (III); eutectic alloy: 96.3% Ga + 13.7% Sn (IV); and five hypereutectic alloys with Sn content of 20% (V), 35% (VI), 50% (VII), 80% (VIII), and pure tin (IX). A nonequilibrium state diagram

The TiN/TiAl3/Ti2AlN composite material is fabricated in the filtration combustion mode in nitrogen of porous samples made of the TiAl intermetallic powder consolidated under thermal vacuum treatment. The weight content of each phase, which was 42% TiN, 35% TiAl3, 20% Ti2AlN, and 3% TiAl, is calculated from the X-ray phase analysis data of combustion products. The synthesized composite material containing

The influence of compaction pressure during semidry compaction in a steel mold of zirconia powder partially stabilized by yttria on the phase composition and microstructure of formed compacts, as well as samples sintered at 1400°C for 2 h, is investigated. An aqueous solution of polyvinyl alcohol is selected as a temporary manufacturing binder. The yttria content in the powder synthesized according

Abstract A process for obtaining semifinished products in the form of pipes made of copper alloys for electrical purposes by means of screw rolling is proposed. The results of experimental piercing and rolling of tube samples made of Cu–0.75Cr alloy billets with a diameter of 45 mm are presented. The samples, 43.5 × 10.0 mm in size, obtained after piercing with the use of a two-roll screw rolling mill

Abstract The expected increase in demand for alkali metal raises a concern over the difficulty in extracting Li, Rb, and Cs from hard rock ores. A four-step process is discussed to extract alkali metal from lithium porcelain stone. The process consists of roasting, leaching, evaporation and purification of lixivium, and precipitation of lithium salts. Two types of additives are used to enhance selective

Abstract The effect of K2O on phase relation and viscosity of the CaO–SiO2–25 wt % “FeO”–12 wt % ZnO–3 wt % Al2O3 slags was investigated using the rotating spindle method. Experimental results show that the slag viscosity increases with the first addition of K2O, exhibiting a maximum at K2O content of 1 wt %, followed by a decrease. The activation energy for viscous flow initially increases and then

Abstract The results of a comparative research into the corrosion resistance of an aluminum matrix composite material produced by the oxygen lancing of a prehydrogenated aluminum alloy melt based on Al–Si–Fe with an iron content of over 1.0% and Al–7% Si alloy with an iron content of up to 0.3% modified by ligature 5Al–Ti for 2% are shown. The aluminum-alloy corrosion was conditioned by the film discontinuity

This article is devoted to the formation of amorphous coatings on the steel 35 surface by electrospark treatment in a mixture of crystalline granules. It is revealed by the energy dispersive X-ray spectroscopy (EDS) that formed coatings contain W, Mo, Co, and Ni in various ratios. The weight of granules of various compositions decreases by 11–16 wt % for 6-h treatment due to electric erosion. The mass

MgO is extensively used for various applications. A Venturi jet reactor can help prepare the micro- or nano-sized magnesia via pyrolysis. However, the reactors have an uneven mixing and concentration distribution. The operational and structural parameters of the reactor have therefore been optimized to overcome this issue. The numerical simulations indicate that higher flow rates of MgCl2 at the inlet

Abstract The main tasks of treating a melt of brass are analyzed. A comparison of traditional treatment methods with the proposed method of improving the quality of the alloy is presented. The equilibrium conditions for the decomposition reactions of carbonates are considered when treating the melt in an open and closed ladle. The conditions for the reaction of carbonate decomposition are formulated

The enormous demand for and consumption of nickel in industrial applications has induced the depletion of high-grade nickel sulfide ore, which has inevitably led to the utilization of the substantial deposits of depreciated low-grade nickel-copper sulfide ore. In this work, the mineral phase transformation and sulfation kinetics of nickel, copper, iron, and magnesium in the roasting process were studied

Abstract The research results of the production of long deformed semi-fabricated products by sheet rolling and direct extrolling from aluminum-magnesium alloys with various scandium content are presented. Computer simulation and physical modeling methods are used and the results are verified by pilot testing. The choice of these materials as objects of research is due to the fact that aluminum alloys

Abstract Limonitic and saprolitic laterite ores are used to produce Ni by employing different kinds of processes. Acid leaching is an energy-saving process for pure Ni metal production. The high concentration of Fe in atmospheric acid leaching solution caused difficulties in metal-ions separation. In this work, saprolitic laterite ore was leached by atmospheric acid leaching solution of limonitic laterite

A cast material based on the Nb2AlC MAX phase is formed by SHS metallurgy. The synthesis is performed using the Nb2O5–Al–C mixture with the CaO2–Al high-energy additive. The results of thermodynamic calculations correlate with the experimental data. The substantial influence of the CaO2–Al additive on the thermodynamic parameters and phase composition of the product is established. It is shown that

Abstract A mechanism is proposed for the joint reduction of oxides from multicomponent copper-smelting slag when they are blown with CO–CO2 gas mixtures and an algorithm is developed for its implementation in the form of a mathematical model. The first feature of the proposed mechanism is that the total rate of the overall reduction process is determined by CO consumption in the course of its interaction

Abstract This paper presents an investigation of the effects of aging temperature on the microstructure and shear strength of SAC0307-0.1Ni/Cu solder joints. Single-overlap shear solder joints were aged for 1 h at 80, 130, and 180°C. The microstructure of the interface between the solder and the Cu substrate contained phase of the intermetallic compounds (IMCs) (Cu,Ni)6Sn5 formed along the interface

Abstract A new nonstationary three-dimensional mathematical model of an aluminum reduction cell which makes it possible to perform coupled thermoelectric and magneto-hydrodynamic calculation while taking into account sideledge formation is presented. The model takes into account the nonlinear dependence of the coefficients of electrical conductivity and thermal conductivity of materials on temperature

Abstract Studies have been conducted to establish the patterns of sulfuric acid dissolution of metal sulfides in the presence of environmentally friendly oxidizing agents, ozone and iron(III) ions; determine the parameters and modes of intensified extraction of metals into solution; reduce the consumption of oxidizing agents; and develop the least environmentally intense and most cost-effective methods

The application of the agricultural waste of cashew nut shells (CNSs) from the Ivory Coast is proposed for the production of activated carbon (AC) used in water treatment by the physical activation. Washed and crushed CNSs are carbonized at 800°C. The crushed CNS carbonizate is activated by the physical method in a temperature range from 400 to 700°C. The specific surface (SBET) and porous structure

Abstract This paper investigated the oxidation of fayalite (Fe2SiO4) in iron-rich nickel slag (INS) for iron recycling via an oxidation-magnetic separation method. A phase stability diagram of the FeO–SiO2–MgO–CaO–O2 system drawn by FactSage 7.1 illustrates that magnetite (Fe3O4) can be crystallized from liquid slag in an air atmosphere, but the further oxidation to Fe2O3 in molten slag was extremely

The influence of different methods of producing alloys of the Fe–Cu system from immiscible components is studied. Alloys with limited solubility (LS) in liquid and solid states are impossible to fabricate by conventional metallurgy. This is why developing low-cost and simple technologies for fabricating such alloys and materials based in them, making it possible to specify the necessary level of physicomechanical

Abstract High-purity tin is widely used in advanced technologies such as aerospace, electronic information, and nuclear industry. It has become a key material supporting the development of human science and technology innovation. However, there are few studies on the preparation methods of high purity tin. A novel technique was developed to purify 99.99682% tin by zone refining in an argon atmosphere

Abstract Experimental antifriction aluminum alloys based on an Al–5% Si–4% Cu system with the addition of low-melting components such as Bi, Pb, In, and Cd have been studied. An optimal heat treatment mode has been adjusted, including the hardening at a temperature of 500°С with further aging at 175°С. The tribological testing have been carried out according to a pad–roller scheme (Steel 45 as the

Abstract The results of investigations into increasing the contrast of process properties of calcite and scheelite due to the combined application of water glass with salts such as sulfates of aluminum, zinc, iron, magnesium; mixtures of water glass and calcium chloride; sodium carboxymethyl cellulose (CMC); combinations of sodium oleate with low-polar compounds (neonol and fatty iso-alcohols); and

This work is devoted to the fabrication of ZrB2–ZrSi2–MoSi2-based composite powder ceramics by self-propagating high-temperature synthesis (SHS) according to the scheme of magnesium thermal reduction from oxide feedstock and its subsequent hot-pressing (HP) consolidation. The combustion of reaction mixtures has rather high adiabatic temperatures in a range of 2060–2120 K and burning rates in a range

Abstract The most currently widespread method of flux-free melting of magnesium alloys is melting under a protective gas atmosphere consisting of inert carrier gas with a small additive of active gas. The ML19 (Mg–Nd–Y–Zn–Zr) casting magnesium alloy contains yttrium and neodymium; these metals are rather active. The interaction of similar alloys with protective gas atmospheres is studied poorly and

Abstract Electrolytic production, which is one of the most power-consuming and environmentally dangerous technologies, occupies a special place in nonferrous metallurgy. For example, aluminum production by the electrolysis of cryolite–alumina melts is accompanied by atmospheric emissions of fluorine-containing substances, sulfur-containing substances, and hydrocarbons, while magnesium production is

Abstract The phase and structural transformations of a powder hard magnetic alloy of the Fe–30% Cr–27% Co–1% Si–0.07% B system with a metastable α1 + α2 phase composition, elevated cobalt content, and high level of magnetic properties are studied. The density and variation coefficient of the concentration of main elements of sintered billets at a level of deformable analogs are attained by sintering

Abstract The dynamic behavior (formation/dissolution) of the ledge, depending on the electrolyte overheating temperature, thermal resistance of the lining material, and composite of the cryolite–alumina electrolyte, is studied experimentally using a model installation mimicking the actual conditions of the electrolytic aluminum production. A window that enabled the change of the lining material is

Abstract Sorption of scandium by activated carbons of VSK, DAS, and PFT brands of different origin (coconut shell, anthracite, and thermosetting-plastic waste, respectively) from sulfuric–chloride solutions (pH 2) simulating the composition of solutions for the underground leaching of complex ores is studied in batch conditions. It is established that the sorption of scandium by carbons of DAS and

Abstract New methods to monitor metal burning in D16 and V95 aluminum alloys based on using energy-dispersive X-ray spectral analysis (EDS analysis) are shown. It is known that the reduced properties of aluminum-based materials are often associated with the presence of metal burning in the structure. The structural changes caused by metal burning (partial melting of eutectics and excessive low-melting

Abstract Trends and prospects for the development of industry according to materials of European and world congresses on powder metallurgy and publications in leading specialized foreign editions are analyzed. Trends of the stable development of the production of powder structural parts for the automotive industry in developed countries, including using assembly technology during joint sintering, are

Abstract Diffusion and homogenization in “iron (5 μm–nickel (5 μm or 50 nm)” powder systems of various degrees of dispersion during sintering (900 and 1000°C), as well as spark plasma sintering, are investigated using the Matano–Boltzmann method. Calculated diffusivities in pairs of micron powders sintering without applying pressure (900°C, 6 h) and by the spark plasma method (900°C, 5 min) in these

Abstract Powders based on the ZrO2–7 wt % Y2O3 system, into which oxides of rare-earth elements (REE)—La, Nd, and Pr—were introduced in the form of the concentrate in an amount from 5 to 15 wt %, are prepared by chemical coprecipitation from inorganic precursors. It is established that an increase in the concentrate content leads to a shift in the temperature maxima of thermal effects into the range