Browsing by Author "Boiarkin, Viacheslav V."

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Improvement of Cooling Regimes for the Formation of Mechanical Properties of Hot-Rolled Sheets
(Український державний університет науки і технологій, ІВК «Системні технології», Дніпро, 2025) Likhosha, M. L.; Boiarkin, Viacheslav V.
ENG: The global demand for hot-rolled sheets made of steel and non-ferrous alloys continues to grow steadily due to their versatility and wide range of applications. Hot-rolled products serve as a basis for further processing into cold-rolled materials used in the automotive industry and other sectors. At the same time, a significant portion of hot-rolled sheets is used directly in construction industry and mechanical engineering, as well as being in demand in the energy and shipbuilding industries. High requirements for strength, plasticity, durability and corrosion resistance of hot-rolled sheets dictate the need for precise control over temperature regimes throughout the entire technological process. Optimization of the pre-rolling heating and controlled cooling regimes of hot-rolled products allows the modification of the metal’s microstructure and mechanical properties. The use of mathematical modeling will allow for the study of thermal regimes and the development of recommendations for their improvement.
Influence of Deformation Parameters on Mechanical Behaviour of Aluminium-Magnesium Roll-Bonded Composites with Kirigami-Structured Inlays
(Dnipro University of Technology, Dnipro, 2025) Frolov, Yaroslav V.; Nuernberger, Florian; Konovodov, Dmytro V.; Bobukh, Oleksandr S.; Boiarkin, Viacheslav V.
ENG: Purpose. To assess how the mechanical properties of a composite material comprising EN AW 1050 aluminium, and kirigami-inspired structure made from E235 steel and AZ31 magnesium alloy, depend on the initial configuration of its components and the degree of reduction during roll bonding. Methodology. The study involved roll-bonding five-layer composite sheets with the following configuration: two of the internal layers consisted of a kirigami structure implemented using an expanded metal mesh made from low-carbon steel. The outer matrix layers were aluminium alloy sheets, and the core matrix layer was formed from magnesium alloy sheets. The transformation of the kirigami structure within the composite was assessed using X-ray analysis. The mechanical properties of the composites were evaluated using three methods: impact bending tests, three-point bending tests and ball indentation tests. Findings. Experimental investigations yielded data on how the kirigami structure transforms within the five-layer composite, depending on the rolling reduction. It was found that a rolling reduction of 55 % provided an isotropic mechanical response. Mechanical testing showed that the energy absorption capacity was enhanced by 60–70 % with kirigami inlay, even under complex stress–strain conditions. The stiffness of the reinforced composite was found to be several times higher than that of unreinforced aluminium. Originality. This study is the pioneer in analysing the combined effect of component configuration and rolling reduction on the mechanical behaviour of a five-layer aluminium-magnesium composite reinforced with a steel kirigami structure. The study demonstrated that deformation parameters ensured reliable bonding between the aluminium and magnesium layers and significantly enhanced mechanical performance by controlling the transformation of the kirigami structure. Practical value. The findings of this study enhance our understanding of how rolling reduction and initial layer configuration affect the deformation behaviour of multilayer Al-Mg composites. They also lay the groundwork for designing novel composites reinforced with kirigami structures for advanced structural applications.
Kirigami Inspired Solid-State Alloying (KISA) Method of Creation of Functionally Graded Materials
(Український державний університет науки і технологій, ІВК «Системні технології», Дніпро, 2025) Frolov, Yaroslav V.; Bobukh, Oleksandr S.; Boiarkin, Viacheslav V.; Konovodov, Dmytro V.
ENG: Kirigami-inspired solid-state alloying (KISA) is an innovative technique that applies kirigami principles to control the distribution of alloying elements within a matrix during pressure bonding. By employing precise cuts and patterns, KISA manipulates diffusion and precipitate formation at micro- and nanoscale levels, leading to tailored material properties. This method eliminates challenges associated with conventional liquid alloying, such as oxidation and element loss, while enabling controlled microstructure evolution through roll bonding and heat treatment. Key advantages include improved phase distribution, enhanced interfacial properties, and adaptability for various material types, including powders and amorphous substances. KISA presents new opportunities for designing functionally graded materials with customized mechanical, electrical, and thermal characteristics.
Transformation of the Kirigami-Type Deformable Inlay during Roll Bonding
(Dnipro University of Technology, Dnipro, 2025) Frolov, Yaroslav V.; Konovodov, Dmytro V.; Bobukh, Oleksandr S.; Boiarkin, Viacheslav V.
ENG: Purpose. To quantitatively analyze the deformation of kirigami-type deformable inlays during the roll bonding process using soft outer matrices, with the goal of predicting their behavior within the composite structure. Methodology. The research involved the fabrication of three-layer composite sheets through roll bonding. Expanded meshes made of mild steel and stainless steel served as the inlay phase, while copper and aluminum alloy sheets were employed as matrix materials. The transformation of the inlay phase within the composite sheets was evaluated. Findings. The experimental investigation yielded data on the deformation behavior of kirigami-type inlays embedded within three-layer sheets during roll bonding. It was observed that using an aluminum matrix induces greater axial metal flow in the deformation zone, leading to a significant increase in the mesh distortion angle. A copper matrix primarily causes flattening of the mesh cells with minimal changes to their angular deformation. In contrast, rolling the steel mesh without a matrix results in negligible angular distortion until the rolling reduction exceeds 50 %. Originality. This study represents the first quantitative analysis of the geometric transformation of kirigami-type deformable inlays as a function of deformation magnitude and matrix material properties during roll bonding. Understanding the shape transformation of the reinforcing phase within the composite sheet enables more accurate prediction of the contact area between the matrix materials during the bonding process. Practical value. The findings of this research provide a basis for predicting the final geometry of kirigami structures within composite materials.