To investigate the forming mechanism of shaped tubes in roll forming of circular tubes, this study conducted roll forming experiments on shaped tubes with different materials and geometries. Using a 30 × 30 mm Q345B square tube as the target, samples were taken from both the planar and corner regions for mechanical property testing and microstructural characterization. The results show that in the uniaxial tensile tests of the planar region, 20Mn2 exhibited the highest tensile strength. Fracture surfaces of all materials displayed evident dimples, second-phase particles, and tear ridges, indicating significant ductile fracture characteristics. In the hardness tests of the corner region, the inner side showed noticeably higher hardness than the outer side, with the maximum value occurring in the inner area. The dislocation density in the inner corner was greater than in the middle and outer regions, a result of metal flow in the corner area. TEM observations of the corner region revealed substantial dislocation pile-ups at grain boundaries, demonstrating severe plastic deformation in this zone.
The fundamental mechanisms of hydrogen atom incorporation into the tetragonal lattice of the Pd3Mn intermetallic compound (space group I4/mmm, file no. 139) are studied using density functional theory (DFT) and X-ray diffraction. The crystal structure is found to form octahedral interstices coordinated exclusively by palladium atoms (Pd6), which is due to the coincidence of their electronegativities ( χ_Pd = χ_H = 2.20 ) and the optimum cavity radius ( 0.53 Å). Dissolution energy calculations show that the dissolution is exothermic for a concentration n ≈ 1.0 (Pd3Mn–nH), after which the dissolution energy decreases due to repulsion between H atoms. An analysis of the projected density of electronic states (PDOS) has revealed the following key effects: a shift of the Fermi level by 0.4 eV deep into the valence band, the appearance of a hybrid peak at ε ≈ −2.5 eV (s(H)–d(Pd)), and the suppression of DOS at the Fermi level indicating an increase in thermodynamic stability. The incorporation of even a single H atom leads to a local lattice distortion and a symmetry lowering from tetragonal (I4/mmm) to triclinic (P1), which is a direct consequence of electronic density localization and the formation of a directional covalent-like bond. The maximum theoretical hydrogen capacity is estimated at 0.80 wt
This article investigates the process of electrochemical removal of phosphate ions from washing solutions generated in aluminum production. A distinctive feature of these solutions is the presence of a significant concentration of aluminum (46.42 g/L) in the form of [Al(OH)4]–, in addition to phosphate ions (up to 1.7 g/L). The influence of operational parameters—initial pH, process time (τ), initial phosphate ion concentration, interelectrode distance, and current density—on the efficiency of phosphate removal by electrocoagulation using aluminum electrodes was studied. It is shown that electrochemical dissolution of the aluminum anode followed by hydrolysis of Al3+ ions in solution leads to the formation of an amorphous coagulant precipitate, aluminum hydroxide. It was established that electrolysis of the solution with an aluminum anode at a current density of J = 10 mA/cm2 results in phosphate ion removal exceeding 90 SO_4^2 - , PO_4^3 - , F–, Cl–, VO_4^3 - ) present in washing solutions obtained during alunite processing on the degree of phosphate removal was also evaluated.
The deep drawing of multi-layer sheets is crucial for the production of lightweight, high-strength components in the automotive and aerospace industries. This study examines the drawing depth of St12/Al 3105 two-layer sheets in square deep drawing through both experimental and numerical approaches. The Gurson–Tvergaard–Needleman (GTN) damage model, implemented via a UMAT subroutine in ABAQUS/CAE, predicts material failure with errors below 1
This study investigates the hardening characteristics of magnetite-anthracite-calcium hydroxide composite pellets carbonated at 600°C in a CO2 atmosphere, with the objective of ensuring adequate mechanical strength for pre-reduction in shaft kilns. During carbonation, Ca(OH)2 and Fe3O4 were transformed into CaCO3 and Fe2O3, respectively. The influence of iron ore particle size on the post-carbonation strength of composite pellets was systematically examined. Results demonstrate that reducing particle size accelerates the carbonation reaction and significantly enhances pellet strength. Specifically, carbonated pellets prepared from conventional magnetite ore exhibited a compressive strength of approximately 262 N/pellet, whereas those fabricated from ultrafine-pulverized ore achieved strengths reaching 800 N/pellet. These findings indicate that ultrafine-pulverized magnetite concentrate, in combination with coal and calcium hydroxide, can be utilized to produce composite pellets suitable for pre-reduction in shaft kilns utilizing waste heat from smelting reduction furnaces.
TiC–Ni composite powders, exhibiting a microstructure in which Ni surrounds TiC particles, were synthesized from the reaction powder mixtures of titanium, carbon black and nickel by self-propagating high-temperature synthesis(SHS). Subsequently, TiC stainless steel-bonded cemented carbide was fabricated using the as-synthesized TiC–Ni composite powders by conventional powder metallurgy (PM). The effects of ball milling time on the characterization of TiC–Ni composite powders were investigated, along with the mechanical properties and corrosion resistance of the cemented carbide. X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS), and laser particle size analysis(LPSA) were used to characterize the initial reactant mixtures, the synthesized TiC–Ni composite powders, and the final sintered cemented carbide. The density, hardness, and transverse rupture strength (TRS) of the cemented carbide were analyzed. The corrosion resistance of the cemented carbide was evaluated by the immersion test. The results showed that the desired TiC–Ni composite powders can be obtained when the ball milling time of the reactants in the SHS process is more than 9 hours. Compared to the TiC powder synthesized by carbothermal reduction, the cemented carbide fabricated using TiC–Ni composite powders synthesized by SHS exhibited enhanced mechanical properties with a relative density of 99.9
In this work, density of Ga95Ho5 alloy was experimentally studied for the first time over a wide temperature range using absolute variant of gamma absorption method and viscosity of its melt was investigated using damped torsional vibrations method (Shvidkovskiy method). The characteristic temperatures of the alloy were determined using differential scanning calorimetry (DSC). It has been shown that the melting process involves a number of reactions and the alloy transitions to liquid state at a temperature of 975 K. It is established that Ga95Ho5 melt is characterized by long-term non-monotonic processes of transition to equilibrium state— relaxation processes with a duration of approximately 200 min.
The use of cubic β-splines is considered to simplify the computation the deformation zone surface during steady flow and to calculate the components of strain rate tensor ξij on rolling alloy steels in simple grooves. The method of rolling grids is used as a basis for studying the state of stress on the free and contact surfaces of a strip. The coordinates of the deformed mesh serve as the initial information for calculating and describing the deformation zone surface.
Silicon carbide (Si10C20) has been developed and examined as an anode material for TM-doped LIBs, specifically using Sc, V, and Mn as dopants. These dopants form nanoclusters such as Si10C20Li2, Si10C20LiSc, Si10C20LiV, and Si10C20LiMn. A significant amount of research has been conducted on how these complexes can save energy using computational methods, including analyses of charge density differences (CDD), total density of states (TDOS), and localized orbital locator (LOL) for these hybrid nanoclusters. By adding elements like lithium, sodium, beryllium, and magnesium, the negative charge on carbon can be increased, making it a better electron acceptor in these nanoclusters. A higher ratio of silicon to carbon in these nanoclusters can enhance battery capacity during the energy storage process and improve the battery’s performance at higher rates by increasing electrical conductivity. This suggests that TM doping can significantly enhance the electrochemical performance of Si10C20, making TM-doped Si10C20 a great candidate for LIBs. These materials are expected to greatly improve the energy storage capacity, the speed at which batteries can charge and discharge, and their longevity in the next generation of lithium-ion batteries.
Vitrification is one of the most frequently used approaches for immobilization of radioactive wastes (RAW). For its safe and stable storage the glass matrix into which the wastes were embedded must meet a number of requirements concerning its properties, and thermo-physical properties are of particular importance. In this work we have focused on borophosphate glasses which are prospective materials for vitrification of fluoride RAW from molten salt reactors. The effect of rare-earth fluorides LnF3 (Ln = La, Ce, Nd), considered as fission products and stable analogues of actinides, on thermo-physical properties of the glasses was thoroughly studied. The concentration of LnF3 additive did not exceed 1.5 mol
To improve the pickling efficiency of oxide scales formed on hot-rolled 45# steel, this study investigates the influence of oxide-scale microstructure on pickling behavior by employing a series of representative oxide scales generated under simulated coiling conditions. The results demonstrate that oxide scales formed under different coiling parameters exhibit pronounced differences in layered structure, phase constitution, and interfacial characteristics, which in turn lead to significant variations in pickling efficiency. In particular, the presence of continuous metallic Fe layers and eutectoid structures within the oxide scale markedly impedes the pickling process, whereas oxide scales dominated by FeO are more readily removed, thereby facilitating more efficient pickling.
To elucidate the regulatory mechanisms of Mo addition on the microstructure and wear resistance of CoCrCuFeNi high-entropy alloy coatings, plasma cladding was used to fabricate two types of coatings (CoCrCuFeNi and CoCrCuFeMoNi) on Q235 steel substrates. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), microhardness testing, and friction-wear tests were employed to investigate the effects of Mo incorporation on the phase composition, microstructure, elemental distribution, and mechanical properties of the coatings. The results demonstrate that Mo addition does not alter the core “FCC + BCC dual-phase” structure of the coatings but significantly promotes BCC phase formation. Furthermore, Mo refines coating grains via heterogeneous nucleation, suppresses Cu elemental segregation, and enhances microstructural uniformity. In terms of mechanical performance, the Mo-containing coating exhibits higher microhardness and superior performance stability than the Mo-free counterpart, while its wear resistance deteriorates substantially. The wear mechanism transitions from a composite mode of mild abrasive and oxidative wear to a severe composite mode involving abrasive, oxidative, and adhesive wear. The core regulatory mechanism is the “competition between strengthening effects and defect-induced deterioration effects”: positive effects (solid solution strengthening, grain refinement strengthening, and segregation inhibition) moderately enhance hardness. In contrast, negative effects (lattice distortion and reduced crystallinity arising from the significant atomic radius difference between Mo and other elements) dominate, exacerbating oxide film instability and thus impairing wear resistance. This study clarifies the action mechanism of Mo in CoCrCuFeNi coatings, enriches the elemental regulation theory of high-entropy alloy coatings, and provides data support and theoretical references for subsequent composition optimization of high-performance wear-resistant coatings.
In the current work the manufacturing, microstructural features, mechanical attributes, and corrosion behavior of an AM60 magnesium alloy reinforced with a Mg–Al–Ni–Cr–Fe high-entropy alloy (HEA) phase are examined. The composite was produced via a stir casting technique setup, ensuring uniform dispersion of HEA particles within the magnesium matrix. Microstructural analysis revealed well-dispersed HEA particles, slight grain refinement, and the formation of intermetallic phases at particle—matrix interfaces. The incorporation of the HEA phase significantly enhanced the material properties such as Vickers micro-hardness increased from 76 HV in the base AM60 alloy to 102 HV in the composite, while the corrosion rate decreased from 10 to 5.84 mm/year. Overall, the microstructural and compositional analyses demonstrate that the addition of the HEA phase effectively enhances particle reinforcement, modifies matrix morphology, and contributes to improved hardness and wear resistance of the AM60–HEA composite.
This article employs laser cladding to enhance the microhardness and microstructure properties of the Titanium alloy applied to the WC–Ni–Cr powder coating. The 50 wt
The stretching process of a slanted-floor box product was simulated to analyze the deformation characteristics compared to a flat-floor box product. A stretching simulation model of the slanted-floor box was developed by DYNAFORM software. Characteristics of the model is that the distance between the blank holder and the die is set equal to the sheet thickness. The flow characteristics of flange metal, stretching limit, thickness distribution and the force acting on the tool were analyzed to investigate the deformation characteristics compared to the stretching of a flat-floor box product. Using orthogonal test method, a regression equation to determine the maximum forming depth with geometrical parameters of the slanted-floor box product under the condition of fixed process parameters (coefficient of friction between tool and workpiece and fillet radius of die) was developed, and its accuracy was validated through the stretching process of a terminal box. The average relative error of the developed equation is 2.35
The results of Ansys Fluent 21.2 computer simulation of the processes that occur in a blast furnace tuyere are compared for four variants at the same supply of steam with blast, which differ in the amount of steam supplied together with natural gas. When the flow rate of steam supplied with natural gas increases, chemical reactions within the tuyere proceed more completely, which is accompanied by an increase in the blast temperature and velocity and provides higher uniformity in the distribution of temperature and chemical reaction participants over the cross section of the channel.
The two-phase method is modified to calculate liquid–liquid phase equilibria in the LiF–CsI reciprocal mixture. This approach uses the Born–Mayer pairwise approximation to describe interionic interactions, which is advantageous. The calculated miscibility gap fragment is in general agreement with available experimental data. Our calculations of the concentrations of the coexisting liquid phases reflect the primary experimental trend that the solubility of LiF in CsI increases more rapidly than the solubility of CsI in LiF as temperature rises.
The effects of substrate material on the morphology and electrocatalytic properties of porous nickel foam electrodeposited from chloride solutions onto cylindrical electrodes made of copper, nickel, carbon steel, stainless steel, and zinc-coated aluminum are examined. The substrate material affects the number and size of macropores, porosity, the morphology of the dendrites forming the pore walls, and the specific surface area of the porous nickel electrodeposit (foam). Morphological differences between foams deposited on different substrates affect the electrocatalytic activity of foams in the hydrogen evolution reaction in an alkaline medium. The electrochemical properties of the foams are estimated by measuring hydrogen evolution depolarization relative to a smooth nickel electrode. Due to their high porosity, foams deposited on nickel substrates demonstrate high electrocatalytic activity. Lower porosity and activity are typical of deposits on copper and carbon steel substrates. The lowest porosity occurs on stainless steel and aluminum substrates, where adhesion of the nickel foam is also poor.
The temperature dependences of the densities of molten alkali metal chlorides are calculated using a statistical theory of liquids. The equation of state used in the work makes it possible to take into account both the charge–dipole contribution and the dipole–dipole correction to the interionic interaction in melts using a charged hard sphere model. This version of the equation of state has been derived using the thermodynamic perturbation theory in combination with the virial theorem, which relates expressions for various contributions to the internal energy and pressure of a liquid. The calculation results are shown to qualitatively and quantitatively agree with the experimental data on the temperature dependences of the densities of molten chlorides. The errors in calculating densities in this case are no more than 3.5
A series of substituted ZnGa2 – xInxO4 (x = 0–0.4) spinels is synthesized using nitrate–glycol gel decomposition at temperatures of 300–900°C. The material is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The introduction of In3+ ions into the spinel structure is found to cause partial amorphization and to retard crystallization at a sintering temperature of 500°C. A single-phase spinel forms at temperatures of 700 and 900 °C and low substitution (up to x = 0.1), and the hexagonal InGaZnO4 phase appears at higher indium concentrations. The upper solubility limit of In3+ in the spinel structure, which is detected when reflections from the foreign hexagonal InGaZnO4 phase appear, is x = 0.20 and x = 0.10 for sintering temperatures of 700°C and 900°C, respectively. The calculation of the unit cell parameters confirms Vegard’s law in the region of low indium substitution. For the ZnGa2 – xInxO4 solid solutions synthesized at a sintering temperature of 700°C, the lattice parameter is a = 8.3264 ± 0.0005 Å and 8.3419 ± 0.0007 Å for x = 0 and 0.10, respectively, and for a sintering temperature of 900°C and x = 0 and 0.10, the lattice parameter is a = 8.3229 ± 0.002 Å and 8.3436 ± 0.0008 Å, respectively. The possibility of introducing a larger amount of In3+ ions into the spinel structure is demonstrated, which can be promising for using the material in the field of printed and flexible electronics.
