International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The features of the chemical and phase composition, structure and transformations in boride inclusions in the steel 04H14Т3R1F, used for the manufacture of hexagonal pipe covers used during transportation to the place of regeneration and storage of spent fuel assemblies (FA) of nuclear power plants, have been studied. It has been established that steel 04H14Т3R1F contains two types of boride inclusions (Ti,Fe,Cr,V)2B with a shell of (Ti,Cr,V)2B and (Fe,Cr)2B, which have significant chemical heterogeneity. It is shown that in the process of hot deformation the phase and structural transformations occur: a change in the composition of borides due to the redistribution of elements, dynamic diffusion fragmentation and release of “satellite” particles, brittle destruction of borides, boride transformation. The behavior of boride inclusions and their influence on the mechanical properties of 04H14T3R1F steel at different plastic deformation temperatures was studied.

Digital image correlation tests were performed during cold deformation on aluminum – magnesium alloy. The comparison of strain distribution obtained with 2D and 3D digital image correlation was analyzed and compared. The comparison of strain distribution in static tensile tests was performed with qualitative strain distribution and quantitative line analysis and strain-time relationship. The tests showed that there were no significant differences in the strain values and distributions obtained using the 2D and 3D digital image correlation when comparing the qualitative and quantitative results.

The article presents the results of studies of the structure and properties of nanodispersed silicon carbide particles using the method of infrared spectroscopy of disturbed total internal reflection, as well as electret thermal analysis. Temperature ranges of the occurrence of TST in the polymer matrix have been established, which may be due to the processes of melting and oxidation of the polymer matrix, accompanied by the release of charge carriers. The activity of silicate-containing particles used to modify polymer matrices has been analyzed. It has been shown that the introduction of SiC particles into the polymer increases the intensity of TST peaks. The prospects of using ultrafine SiC particles obtained from natural raw materials for the modification of polymer materials are considered.

Cenospheres are used in a variety of applications, including as fillers in building, construction, plastic, and composite materials. The aim of this paper is to evaluate the effect of particle size on the mechanical-acoustic properties of cenosphere powders, which were produced in two different sizes. The mechanical-acoustic properties of the studied powders were experimentally determined based on the frequency dependencies of the sound absorption coefficient, using the transfer function method. It can be concluded that not only particle size, but also powder bed height and the excitation frequency of acoustic waves, significantly influenced the mechanical-acoustic properties of the studied cenospheres.

The paper briefly discusses the main features of radial-shear rolling and provides an overview of its effect on the formation of an ultrafine-grained structure in various non-ferrous and ferrous metals and alloys. The conducted review showed that radial-shear rolling is the most promising way to form an ultrafine-grained structure in long bars made of both non-ferrous and ferrous metals and alloys, as well as from various composite materials.

X-ray diffraction analysis of the Fe-35%FKh800-(0.38-2.2%)TiB2 system samples showed that a multiphase composition of materials is formed during the sintering process. The basis of the sintered composite is the ferrite α-Fe phase, which is a metallic ironchromium matrix, with γ-Fe, complex iron-chromium carbide (Fe,Cr)7C3, and carboboride phases in small amounts: borocementite – Fe3(B0.7,C0.3) with a rhombohedral lattice and carboboride Fe23(C,B)6 with a cubic lattice and a number of carbides (Cr7C3, Cr3C2). The research established the non-monotonic nature of the effect of the TiB2 additive content on the lattice parameters of the ferrite α-Fe and austenitic γ-Fe phases, as well as on the change in the intensity of the 111 line of the austenitic phase. According to the phase composition data and studies of the fine structure (substructure) of the sintered samples of the Fe-FKh800-TiB2 system materials, it can be noted that the components of the TiB2 alloying additive take an active part in the formation of the phase composition, as well as in the process of alloying the matrix phase, which is reflected in the numerical values of the substructure parameters.

A summary study of the development of solar energy and the main factors determining the productivity of photovoltaic systems has been carried out. The predominant surface contaminants of solar panels, reducing the efficiency of photovoltaic installations, and the existing different design types of cleaning systems for their effective removal are examined. The main trends in the development of singlelayer and multi-layer hydrophobic and other oxide coatings with diverse performance indicators suitable for solar panels are traced. In laboratory conditions, experimental self-cleaning coatings (based on compositions with the participation of Y2O3 and ZrO2) deposited by the sol-gel method on vitreous samples were obtained. The structure and morphology of the prepared thin films and the technological conditions for the deposition of nanoscale layers with different functional characteristics were investigated. The experimental results represent a prerequisite for the development of a series of additional compositions and a detailed technological regime for obtaining various modifications of resistant, long-lasting self-cleaning coatings, potentially applicable to photovoltaic panels.

This paper investigates the influence of aging parameters (temperature and time) on thermal, mechanical and structural properties of the EN AW-6060 aluminum alloy. Thermal diffusivity and hardness were measured after applied heat treatments followed by investigation on scanning electron and transmission electron microscopes. Heat treatments included: solutionizing at 550°C for 1 hour followed by quenching in ice water; after quenching samples were aged at two separate temperatures of 180°C and 200°C for 1-8 hours. The results show that hardness gradually increases with aging time achieving peak value of 95 HV10 after aging at 180°C for 5 hours. Thermal
diffusivity also increases with both aging time and temperature achieving peak values after aging at 200°C for 4 hours. SEM/EDS analysis show the existence of finely distributed precipitates containing Mg, Si and Fe. TEM investigation confirms the existence of rod-shaped precipitates several nanometers in length.

Here we present data on the preparation and adsorption properties of mixed zinc-calcium phosphates in aqueous dispersions. The phosphates were prepared by co-precipitation from aqueous solutions followed by autoclaving. The effects of various Ca/Zn initial molar ratios and the type of Ca- and Zn-precursor salts (chlorides and acetates) on the structure, morphology and adsorption properties of the obtained phosphates were investigated. Preliminary data on the adsorption of methylene blue indicated that the as obtained mixed zinccalcium phosphates are promising candidates for application as adsorbents.

In this article, the residual strength of PE geocells after accelerated aging is experimentally investigated. The characteristic is of key importance for the application of geocells, as it is related to their service life.The durability test is defined as essential in the applications standards of the product-EN 13 255:2016,EN 13 251:2016.

Steel reinforcing bars have not performed well in applications where members were subject to corrosive environments. Alkaline concrete protection can provide relatively good protection of the steel reinforcement, but when these are exposed to an aggressive environment or the protection breaks down, the reinforcement starts the corrosive process and it leads to rupture and fragmentation of the protective layer of concrete.
These reasons lead to high maintenance costs, repairing or even replacing them. This problem prompted a lot of researchers to seek alternative materials with characteristics better than steel to be used in construction. GFRP bars, which are fibers with high resistance immersed in a polymer resin matrix, with a high tensile resistance and also resistant to corrosion, emerged in the 1990s as an alternative to replace steel rods. The use of GFRP is increasingly accepted by the countries, which are trying to create or adopt special codes for their use in building structures.
This paper will take a quick look over GFRP materials and their mechanical properties, but also will aim to provide some ideas on the study of concrete members reinforced with GFRP bars and their design based on SLS method as it rapresents the most problematic one, focusing on deflections of GFRP reinforced beams.

The physic-technological basis for fabrication of bulk rods and plates of amorphous, amorphous-nanocrystalline and 100% nanocrystalline alloys at melt cooling rates from 80 to 3200 K/s with crystal sizes from 10 to 50 nm has been developed. The multiphase structure formed in the initial bulk samples, as well as in the process of nanocrystallization of amorphous ribbons, is characterized by record microhardness values of 17-22 GPa. Amorphous powders (20-100 μm) of Fe55Ni8Co6Mo4Cr2V1Al2P9C6B5Si2 and Fe61.37Co6.84Cr3.78V0.85W0.82Mo1.06Nb0.85B19.87C1.99Si2.57 alloys are used to create a wear-resistant coating on structural stainless steels and low-carbon St3 by the gas-thermal “cold” method » sputtering and subsequent melting of the applied layer.The values of microhardness (Hμ) of nano-coatings significantly exceed the microhardness of all known tool steels. Examples of technology transfer and practical using of developed amorphous and nanocrystalline alloys are presented.