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Modern materials science is focused on the development of steels with a range of performance characteristics, including high strength, wear resistance, corrosion resistance, and long-term performance in various conditions. Special attention is paid to the control of the microstructure of steels at the crystallization stage, which allows for the improvement of metal properties without significantly increasing the cost of the manufacturing process. One of the promising methods of microstructural engineering is the modification of steels with dispersed particles of refractory compounds, such as titanium carbide (TiC), zirconium carbide (ZrC), and tungsten carbide (WC). However, the processes of dissolution, dissociation, and interaction of such ceramic particles with the metal melt, as well as their influence on the formation of the microstructure and properties under the conditions of non-equilibrium crystallization, which is typical for centrifugal casting, are not sufficiently studied for austenitic stainless steels. In this work, the influence of dispersed carbide particles of TiC, ZrC, and WC, which are introduced into the melt of austenitic stainless steel (Cr ≈ 18%, Ni ≈ 10%) during centrifugal casting, on the redistribution of alloying elements, the formation of the microstructure, and the mechanical properties of the material is investigated. Special attention is paid to the kinetic nature of the dissolution and interaction of the carbides with the melt, as well as the directional distribution of elements across the cross-section of the billets. The study includes the analysis of the distribution of Ti, W, and Zr across the cross-section of the centrifugally cast billets, the study of the microstructure and phase composition of the inclusions using SEM/EDS, and mechanical testing. It is found that the implementation of dispersion hardening leads to an increase in the tensile strength by up to ~22% compared to the initial alloy (from 496 to 612 MPa), while the impact strength decreases by 5–25% (from 110 to 82 J/cm2) depending on the type and quantity of the introduced particles. The analysis of microhardness shows the presence of a gradient of local properties across the cross-section of the centrifugally cast billets, with microhardness values ranging from ~110 to 195 HV0.5. For the modified samples, the relative difference between the inner and outer zones is ~5–20%, reflecting the combined effect of non-equilibrium solidification, redistribution of alloying elements, formation and spatial distribution of secondary phases, and local structural heterogeneity. These results confirm the possibility of controlling the distribution of properties within a single billet.

The article presents the results of modeling and experimental studies of the ingotless rolling-extrusion (IRE) process of Al-5Ti-1B alloy rods. The objective of this research is to develop a set of technical and technological solutions for the creation of a technology for producing ligature rods from Al-Ti-B alloys with an effective modifying effect. Using the QForm software package, the temperature and energy-force characteristics of the IRE process for producing 9 mm diameter rods from the investigated alloy were determined at the specified deformation and speed parameters. The optimal process parameters were obtained. The melt temperature was 720 ± 10 °C; the temperature of the billet crystallized in the rolls was 520 °C; the roll rotation frequency was 4 rpm; the strain during rolling was 50%; and the drawing ratio during extrusion should be in the range of 4.7–12.9. It was found that rods of Al-5Ti-1B alloy obtained from the melt by the IRE method have an effective modifying capacity comparable to industrial ligatures made from Al-Ti-B alloys.

The article is devoted to the study of energy-force parameters of combined process \"rolling-equal-channel angular pressing\". The objectives of the work were to determine the forces of rolling and pressing in the deformation by this combined method. The strength calculation of the matrix and the experiment on deformation of AISI 6063 aluminum samples were carried out. During the experiment, the force values were recorded using a tensometric station. The results of the strength analysis showed that this matrix design is suitable for creating an experimental stand of combined process \"rolling – equal-channel angular pressing\", since the calculated safety margin is sufficient to implement the pressing under extreme conditions. Analysis of the results of force measurement showed that rolling forces at all stages of deformation exceed the corresponding pressing forces, which is a necessary condition for the implementation of this combined process. The obtained results can be used in the design of experimental stands that implement investigated combined process. At the same time, the used tensometric technique for studying strength characteristics is suitable for the case of calibrated rolls.

The Zircaloy-4 alloy is a key structural material for nuclear reactor cores. However, its behavior under warm deformation conditions and during phase transformations requires in-depth investigation to improve technologies for producing ultrafine-grained (UFG) structures using severe plastic deformation methods. This work presents a comprehensive study of the rheological properties, phase stability, and microstructural evolution of the alloy in the temperature range from 20 to 950 °C at strain rates of 0.5 and 15 s−1. The experimental part included plastometric testing, dilatometric analysis, and microstructural characterization. It was established that the optimal window for plastic deformation corresponds to warm deformation at 650 °C. Dilatometric analysis confirmed that heating to 650 °C ensures the preservation of a stable initial α-phase structure, since the formation of secondary phases and the α→β transformation are initiated at higher temperatures, namely 694 °C (onset) and 847 °C (completion). At 650 °C, the deformation resistance decreases by approximately 70% compared to cold processing, while the strain-rate sensitivity of the flow stress is minimized. EBSD analysis showed that deformation under these conditions leads to intensive grain fragmentation via mechanisms of dynamic recovery and the initial stages of continuous dynamic recrystallization. The decisive role of the kinetic factor was demonstrated: reducing the strain rate to 0.5 s−1 promotes the formation of a finer and more homogeneous grain structure. In contrast, high strain-rate deformation (15 s−1) results in coarser grains and increased non-relaxed intragranular residual stresses. The obtained results provide a physical basis for optimizing thermomechanical processing regimes and can be used to produce UFG structures in zirconium alloys without the risk of phase degradation.

In case of open-pit mineral resources mining development on the earth’s surface, there is an accumulation of overburden rocks, the volume of which is comparable to the size of the open pit being developed. This is especially relevant when developing large and medium-sized deposits using high-performance equipment, since these deposits typically have high stripping ratios. At the same time, overburden rocks are stored in waste rock dumps without regard for their further use and are practically not used for the production of finished products, with the exception of some quarries of building materials. The waste rock dumps from mining enterprises contain many useful components that can subsequently be extracted and used to produce new products. One of the ways to create waste rock dumps complex is to use container technology for waste rock dump formation at the open pit. The rock delivered from the open pit will be loaded into containers and lifted to the unloading site using a special lifting machine. Based on the theoretical research carried out, container technology was developed for separate storage of rock mass on dumps for subsequent use and the developed working equipment was tested using computer modelling methods. Increasing the boom length will allow the rock to be lifted to a significant height, which will reduce the area occupied by waste rock dumps and ensure the separate placement of rocks with different physical and mechanical properties for their comprehensive processing. Conducted studies have shown that transporting rock to a waste rock dump using containers reduces energy consumption and the cost of the process. Another advantage of the new method of storing rock mass is the reduction of dust emission during the operation of mining equipment on dumps.

Based on experimental studies, a model of the control effect on the plastic deformation process under boundary asymmetric loading conditions has been developed. The regulating factor of plastic deformation unevenness δ, which determines the stress–strain state of the entire deformation zone and the boundary conditions, is presented. The boundary conditions, determined by additional compressive and tensile stresses along the height, generate shear stresses and specific loading regimes at the edges and within the deformation zone itself. The confirmed reduction in interaction, which coincides with the effect of plastic deformation occurring under conditions of force unevenness, is one of the criteria for the controlling effect. A distinctive feature of this approach is the recognition and proof of the existence of a controlling additional effect under conditions of complex force and deformation loading. Theoretical and experimental studies have revealed such effects under various loading conditions. Based on a closed-form problem in plasticity theory and the method of argument functions of a complex variable, a mathematical model of the control process exerted by the metal’s plastic flow zone has been developed. A key feature of the solution to this theoretical problem was the consideration of the interaction between zones under different force loads, represented by a finite-difference scheme in the mathematical model. The decisive influence of deformation unevenness from the working rolls on the force and deformation parameters of the process was demonstrated, with the deformation unevenness factor δ serving as a quantitative measure of this influence. The result obtained through theoretical justification was confirmed by numerical simulation and a comparison of calculated data with experimental data, ensuring the reliability of the result.

The model explicitly incorporates boundary conditions that account for the complex interplay between sections experiencing varying degrees of reduction. This interaction significantly influences the overall deformation behavior and force loading. The control effect is associated with boundary conditions determined by the unevenness of the compression, which have certain quantitative and qualitative characteristics. These include additional loading, which is less than the main load, which implements the process of plastic deformation, and the ratio of control loads from the entrance and exit of the deformation site. According to this criterion, it follows from experimental data that the controlling effect on the plastic deformation site occurs with a ratio of additional and main loading in the range of 0.2–0.8. The next criterion is the coefficient of support, which determines the area of asymmetry of the force load and is in the range of 2.00–4.155. Furthermore, the criterion of the regulating force ratio at the boundaries of the deformation center forming a longitudinal plastic shear is within the limits of 2.2–2.5 forces and 1.3–1.4 moments of these forces. In this state, stresses and deformations of the plastic medium are able to realize the effects of plastic shaping. The force effect reduces with an increase in the unevenness of the deformation. This is due to a change in height of the longitudinal interaction of the disparate sections of the strip. There is an appearance of a new quality of loading—longitudinal plastic shear along the deformation site. The unbalanced additional force action at the entrance of the deformation source is balanced by the force source of deformation, determined by the appearance of a functional shift in the model of the stress state of the metal. The developed theory, using the generalized method of an argument of functions of a complex variable, allows us to characterize the functional shift in the deformation site using invariant Cauchy–Riemann relations and Laplace differential equations. Furthermore, the model allows for the investigation of material properties such as the yield strength and strain hardening, influencing the size and characteristics of the identified limit state zone. Future research will focus on extending the model to incorporate more complex material behaviors, including viscoelastic effects, and to account for dynamic loading conditions, more accurately reflecting real-world milling processes. The detailed understanding gained from this model offers significant potential for optimizing mill roll designs and processes for enhanced efficiency and reduced energy consumption.

This research developed a complex physical and mathematical model of the flat rolling theory problem. This model takes into account the influence of many parameters affecting the roll’s gripping capacity and the overall stability of the entire rolling process. It is important to emphasize that the method of the argument of functions of a complex variable does not rely on simplifying assumptions commonly associated with: the linearized theory of plasticity; or the decoupled solution of stress and strain fields. Furthermore, it does not utilize the rigid-plastic material model. Within this method, solutions are developed based on the complete formulation of the system of equations in terms of stresses and strains, incorporating constitutive relations, thermal effects, and boundary conditions that define a well-posed problem in the theory of plasticity. The presented applied problem is closed in nature, yet it accounts for the effects of mechanical loading and satisfies the system of equation. For this purpose, such factors as roll geometry, physical and mechanical properties of the rolled metal (including its fluidity, hardness, plasticity, and structure heterogeneity), rolling speed, metal temperature, roll lubrication, and many other parameters that can influence the process have been taken into account. Based on the developed mathematical model, a new, previously undescribed force factor significantly affecting the capture of metal by rolls and the stability of the rolling process was identified and investigated in detail. This factor is associated with force stretching of metal in the lagging zone—the area behind the rolls, where the metal has already left the deformation zone, but continues to experience residual stress. It was shown that this stretching, depending on the process parameters, can both contribute to the rolling stability and, on the contrary, destabilize it, causing oscillations and non-uniformity of deformation. The qualitative indicators of transient regime stability have been determined for various values of the parameter α. Specifically, for α = 0.077, the ratio f/α ranges from 1.10 to 1.95; for α = 0.129, the ratio f/α ranges from 1.19 to 1.95; and for α = 0.168, the ratio f/α ranges from 1.28 to 1.95.

Grain structure and mechanical properties of 6063 Al alloy subjected to one, two and three passes via combined rolling–ECAP at room temperature were investigated. The yield strength (196 MPa) and tensile strength (242 MPa) after three passes increased by 3.7 times and three times, respectively, relative to the initial annealed alloy (YS: 53 MPa, UTS: 82 MPa). Heat treatment comprising homogenizing annealing (600 °C, 15 min), water quenching from 520 °C and reheating to 100 °C before each pass led to ultrafine grains (600-800 nm) and high yield strength (245 MPa) and tensile strength (277 MPa). The three-pass combined rolling–ECAP process in conjunction with a suitable heat treatment is an effective way to form UFG structure and improved mechanical properties in 6063 Al alloy.

The study presents results of computer simulation by finite elements method of a new metal forming process combining the deformation of a billet with round cross-section on a radial-shear rolling mill and subsequent billet twisting in a forming die with a specific design. To analyze the efficiency of metal processing, the main parameters of the stress–strain state are considered: effective strain, effective stress, average hydrostatic pressure, and Lode–Nadai coefficient. The maximum value of effective strain up to 13.5 is achieved when a screw profile on the billet in the die is forming, which indicates an intensive refinement of the initial structure of the billet. During combined process, the nature of the deformation changes in the transverse direction from the axis of rotation to the surface. The central area of the billet is under the action of tensile stresses. In the peripheral part, compressive stresses grow. In the surface area, Lode–Nadai coefficient is 0.1 approximately, which indicates the high level of shear strain.