In this paper, the microstructural, chemical, and phase evolution of a Ti-6Al-4V alloy fabricated by Laser Powder Bed Fusion (LPBF) and subsequently subjected to electron irradiation was investigated. The LPBF process results in the formation of a nonequilibrium microstructure under rapid solidification conditions (≈10⁵–10⁶ K/s), including acicular α′-martensite, oriented prior β grains, and microporosity (≈0.2–1.0 μm). Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were employed to characterize the material before and after irradiation. SEM observations revealed that electron irradiation increased the agglomerate size from approximately 50–100 μm to 70–150 μm, while reducing pore size from 0.2–1.0 μm to 0.05–0.6 μm. EDS analysis indicated a decrease in Ti content accompanied by an increase in oxygen and carbon concentrations, suggesting surface oxidation and chemical modification. XRD analysis confirmed the transformation of the initial Al–Ti intermetallic phases and the predominance of the hexagonal Ti phase after irradiation. Changes in lattice parameters (a: 2.927→2.936 Å; c: 4.663→4.676 Å) indicate lattice expansion and redistribution of internal stresses. The obtained results demonstrate that electron irradiation significantly affects the structural state of LPBF-fabricated Ti-6Al-4V alloy and can be considered an effective approach for tailoring the process–structure–property relationship in additively manufactured titanium alloys.
The determination of deformation resistance was conducted using a DIL805A/D quenching dilatometer equipped with a hydraulic unit, enabling compression tests during high-temperature forming at specified strain rates. Deformation resistance was experimentally defined for a 5x5 testing matrix, covering deformation temperatures (800, 900, 1000, 1100, and 1200 °C) and strain rates (0.001, 0.01, 0.1, 1, and 10 s⁻¹). Boron-alloyed steel, also known as BCT steel, was used as the experimental material. The Garofalo equation was employed to evaluate the experimental measurements of deformation resistance. This equation describes the hot metal forming process, where deformation resistance is a function of strain rate and temperature. The material constants of the Garofalo equation were determined based on peak stress values obtained from individual deformation curves. The technological process of metal forming is defined by three parameters: strain rate, deformation temperature, and strain level. The Garofalo equation does not include the last parameter, strain level, as an independent variable. Therefore, the Garofalo equation was modified into a strain-dependent model by transforming the material constants into functions of strain. Each material constant was expressed as an n-th degree strain polynomial. In this manner, the third independent variable, strain level, was introduced into the Garofalo equation. To improve the correlation between measured and calculated data, the degree of the strain polynomials was increased. Some publications have utilised strain polynomials up to the 14th degree; however, such a model requires up to 60 material constants. This paper presents the transformation of the Garofalo equation into an energy-based model. The core of this transformation lies in expressing the activation energy constant as a function of strain rate, temperature, and strain level. The material constants Alpha, n, and C remain unchanged, retaining their original meaning as defined by Garofalo. The activation energy is defined by 14 material constants. Together with the remaining three constants, a total of 17 material constants sufficiently define the incorporation of the strain level into the Garofalo equation. A 3D visualisation of the energy model of the Garofalo equation showed that this equation has an extremum, a global maximum of deformation resistance.
The paper presents the results of a study of the physicochemical and mineralogical properties of primary and secondary aluminum slags. It was found that the primary aluminum slags contain 67.8% Al2O3, 12.4% SiO2, 4.58% MgO, 4.59% CaO, and 0.52% Fe2O3. The main phases are spinel (25.4%), sapphirine (26.0%), corundum (25.0%), enstatite (11.9%), and mullite (11.7%). These high-temperature aluminosilicate and oxide phases have high thermodynamic stability and low chemical activity, which significantly complicates the processing of primary slags. The secondary aluminum slags contain 34.9% Al2O3, 4.61% SiO2, 34.7% CaO, 5.70% MgO, and 4.71% Fe2O3. The mineral composition is represented by spinel (20.5%), quartz (10.5%), mullite (8.0%), corundum (13.1%), calcite (27.0%), and breyite (20.9%). Complex aluminosilicate compounds were not detected in the secondary slags, which determines their higher reactivity. The potential of using secondary aluminum slags in metallurgical processing is demonstrated, in particular in the production of ferrosilicon in the form of pellets with the addition of ferrosilicon metal fines, which allows for a reduction in the consumption of natural silica materials and an increase in the resource efficiency of production. The obtained results can be used in the development of energy- and resource-saving technologies for processing aluminum waste.
The growing demand for molybdenum and the involvement of low-grade and man-made raw materials in the processing necessitate the development of effective hydrometallurgical methods for its extraction from complex solutions. In this work, the sorption behavior of molybdenum from sulfuric acid solutions was studied using a weakly basic anionite Purolite A-100. Sorption experiments were performed under static conditions at a temperature of 25 оC with a variation in the initial concentration of molybdenum, and the equilibrium data were analyzed using Langmuir, Freundlich, and Dubinin–Radushkevich models to evaluate the nature of the interaction and describe the sorption process. It is shown that the equilibrium is most adequately described by the Langmuir model (R2 = 0.9868), which indicates the predominantly monolayer nature of sorption. The calculated value of the average sorption energy (E ≈ 6.28 kJ/mol) indicates that the sorption process occurs predominantly through weak physicochemical interactions with a contribution of ion-exchange mechanisms. With an increase in the concentration of molybdenum, a decrease in the degree of extraction is observed, associated with saturation of the active centers of the sorbent, while the formation of sulfate forms of molybdenum and competition of sulfate ions in a sulfuric acid medium have a significant effect. The results obtained characterize the equilibrium behavior of molybdenum in sulfuric acid solutions and can be used in the development and optimization of ion exchange technologies for its extraction from acidic media.
The article presents information on raw material resources and iron ore production worldwide. Kazakhstan is among the world's top ten iron ore-producing states. As high-grade iron reserves become exhausted, ores with low iron content and high impurity levels, including sulfur, are increasingly being processed. Various methods of iron ore desulfurization are discussed: flotation, magnetic, and combined approaches based on pyro- or hydrometallurgical processes that alter the chemical composition of the feedstock. The review provides information on methods for beneficiating low-grade iron ore and their significance for the development of iron and steel metallurgical production.
