Materials. Technologies. Design.

Influence of technological heredity on the process of ion-plasma nitriding in the glow discharge of tool steel R6M5

2025-07-07T11:38:31+00:00

This paper presents the results of determining the effect of preliminary polishing on the structure and depth of the hardened layer after ion nitriding in the glow discharge. Dry electropolishing of the surface of high-speed steel P6M5 with subsequent ion nitriding in the glow discharge contributes to the intensification of diffusion processes and, as a consequence, an increase in the thickness of the diffusion layer with a decrease in the nitride zone due to increased adsorption activity of the surface. Measurement of microhardness showed that pre-polishing allows obtaining more uniform profile of microhardness distribution along the depth of the surface layer due to increased diffusion of nitrogen into the core of the sample. The application of dry electropolishing of the surface of high-speed steel P6M5 before ion nitriding in the glow discharge has prospects for application in the tool industry as an independent method of surface hardening and as a pretreatment before deposition of wear-resistant coating because it allows obtaining on the treated surface of a hardened layer with a smoother hardness gradient.

The effect of the structural parameters of multilayer ion-plasma PVD coatings on their strength and wear resistance

2025-04-07T11:32:31+00:00

This study presents a methodology for investigating the mechanical properties of multilayer ion-plasma coatings using scratch testing. The approach includes constructing contact pressure vs. load dependencies for a hemispherical diamond indenter, determining the maximum contact pressure, and identifying the critical failure loads. The results of microscopic analysis of the coatings and their failure modes are reported, along with measurements of microhardness (HV) and relative wear resistance under gas-abrasive wear conditions, performed in accordance with GOST 23.201-78.

Based on the experimental data, correlations were established between strength and wear resistance characteristics and the structural parameters of the coatings, material composition, thickness, and number of layers. A critical (minimum required) thickness of nitride layers was identified, at which the resistance of the coatings to brittle failure increases significantly, by up to 2.5 times.

It is proposed that multilayer ion-plasma coatings enhance wear resistance via two mechanisms: resistance to the formation of primary (nucleation) microcracks and suppression of their propagation at the interfaces between metallic and nitride layers.

The obtained results can be recommended for the design of multilayer coatings based on titanium, vanadium, and their nitrides, intended to reinforce titanium alloy components, compressor blades of stationary gas and steam turbines.

Design and testing of electrophysical models for typical technological installations of a diamond mining underground mine

2025-05-18T06:29:32+00:00

Industrial production in our country is the main consumer of electric energy. Currently, electric power systems of industrial enterprises are becoming more complex and energy-intensive. Therefore, the development and design of their electric power systems is difficult without the use of computer and simulation modeling programs. The paper considers issues related to the modeling of electric power and electrical engineering systems. The MatLab package was selected as a modeling program. The calculation of the parameters required for modeling was performed. As a result of the study, electrophysical models of typical technological installations of an underground diamond mine were designed, developed and tested, namely, the following problems were solved: the theoretical foundations of the electric drive were studied; the corresponding blocks were selected from the modeling library; electrophysical models of three types of engines were developed; the obtained results were analyzed and modeling errors were determined. The most effective electric drive systems for use in process units of industrial enterprises are designated.

Study of fracture structure of cylindrical samples of 6101 aluminum alloy under static tension after standard heat treatment

2025-07-19T11:19:49+00:00

In this work, the fracture structure of the material after static stretching to failure at room temperature is studied. To improve the group of elastic-plastic properties of metallic materials, thermal hardening and aging methods are used, which is associated with a change in the structure, physicomechanical properties and phase composition. In earlier works, the phase composition of the Al-6101 alloy was shown. This study is supplemented by a new result: inclusions of Fe-based particles along the boundaries of the fracture pits were considered. Their overwhelming majority in comparison to other inclusions was shown, which allowed us to draw a conclusion about their influence on the overall process of destruction as one of the factors influencing direct destruction.

Testing of the method for determining the brittleness temperature range of EP718 superalloy during modeling of pulsed-arc GMA welding

2025-07-27T13:20:02+00:00

In this paper, the testing of the calculation method for determining the brittleness temperature range (BTR₂) during welding of EP718 superalloy caused by diffusion-dislocation phenomena based on the numerical modeling of the thermal stage of 2-pass pulsed-arc GMA welding. The ratio of the stacking fault energy increment to the size of this range dγ/dT was chosen as a quantitative measure for assessing the probability of crack formation in the calculated brittleness temperature range. According to the results of metallographic analysis, the welded joint zones in which the occurrence of near-weld hot cracks is most likely coincide with the region of the brittleness temperature range (BTR₂) calculated during the numerical modeling of the thermal stage of 2-pass pulsed-arc GMA welding in the ANSYS package.

Molecular dynamics study of dislocation formation processes and disorientation regions in a crystal under the influence of a laser pulse

2024-12-06T12:56:16+00:00

It is known that the impact of laser pulses on the metal surface is accompanied by such processes as local heating, melting and even evaporation of the metal, which leads to various structural changes in the surface. In particular, an extended dislocation layer can be observed under the irradiated surface. Obviously, in connection with the widespread use of lasers as a tool for processing materials, the study of the processes accompanying its impact is an urgent task, which, however, cannot always be solved exclusively experimentally and in this case, additional research methods are required. In the presented work, the molecular dynamics method is used to study the structural changes occurring in an iron single crystal subjected to relative deformation of varying magnitudes under the simulated impact of a laser pulse. When constructing the model, it is assumed that such an impact is accompanied only by heating the irradiated material to sufficiently high temperatures. During the simulation, an interphase boundary arose in the computational cell, which is a source of mechanical stresses. Its peculiarity is the presence of surface curvature, leading to uneven distribution of stresses. It is shown that as a result of subsequent structural relaxation, dislocations are formed in the crystal, which are a response to external action, and as the deformation value increases, areas of misorientation are formed. In this case, large deformations are not required for misorientation, but the presence of a liquid phase, as well as excess free volume, is necessary. It is suggested that the occurrence of dislocations and areas of misorientation is also facilitated by tangential stresses created by the interphase boundary.

Study of the influence of application modes on the mechanical properties of wear-resistant coatings based on TiB2-AlSiY

2025-08-09T15:18:08+00:00

The article describes the study of the properties of wear-resistant coatings based on the TiB2-AlSiY system obtained in a vacuum arc deposition unit. The coatings were applied using modes including different bias voltages in order to establish the relationship between the application mode and the properties. After obtaining the coatings, the samples were examined and tested, including the study of the phase composition of the samples by X-ray diffraction, the study of the microhardness of the samples, tribological studies, sclerometry to study the nature of the destruction and the critical load of the coating destruction. The obtained coatings have a number of advantageous properties for use as protection for cutting tools.

Application of a genetic algorithm for selecting the energies of paired interatomic interactions that provide the minimum energy of a given binary ordered alloy of the AnBm composition

2025-06-11T20:28:09+00:00

In this work, we present a methodology for selecting pairwise interatomic potentials for binary metallic alloys AₙBₘ with an fcc lattice that accounts for interactions up to the fifth coordination shell. Extending the interaction range is essential for accurately describing Friedel oscillations, which influence point-defect energies, the stability of ordered phases, the kinetics of plastic deformation, and dislocation mobility. A direct parameter sweep leads to a geometric growth in the number of independent variables and an exponential rise in computational cost (on the order of 10⁴⁵ variants at four-digit precision), rendering such an approach impractical. To achieve efficient optimization, we employed a genetic algorithm, which performs a global search in multidimensional space and reduces optimization time to seconds while preserving accuracy and reproducibility. The resulting potentials were validated by simulating vacancy diffusion via the Monte Carlo Metropolis algorithm on a two-dimensional 15×40 lattice at 100 °C, yielding eutectic, checkerboard, and striped ordering patterns. The combination of a physically grounded multichannel model with an evolutionary optimizer opens new opportunities for detailed large-scale studies of ordering mechanisms and phase dynamics in multicomponent systems. The findings demonstrate the high accuracy and adaptability of the developed approach.

Features of the surface relief of steel and copper samples after HPT processing

2025-07-25T17:01:22+00:00

In this article, the surface of metallic material samples after HPT is investigated and analyzed. The initial blanks were copper and steel 10 (Fe-0.1% C) disks with a diameter of 10 mm and a height of 1 mm. The lower anvil had a groove with a diameter of 10 mm and a depth of 0.5 mm. The upper anvil was “flat” in all cases. HPT deformation was carried out at room temperature with applied design pressure of P = 6 GPa. Cu disks were subjected to HPT with the number of revolutions n = 2.5. Steel 10 (Fe-0.1% C) disks were subjected to HPT with the number of revolutions n = 5. On the basis of our previously obtained data, it was assumed that at HPT of Cu with n = 2.5 revolutions, slippage would be present, but it would not be total, and at HPT of steel with n = 5 revolutions, slippage would be total. The studies have shown that on the lower surface of the copper disk after HPT with n = 2.5 revolutions, a pattern of densely spaced concentric circles-scratches is observed, formed as a result of the incompatible movement of the anvils and the disk surface (sliding of the anvils along the surface) and caused by the presence of irregularities – the relief of the anvils. On the upper surface of the copper disk after HPT a similar pattern of concentric circles-scratches is much less pronounced, which is due to the joint movement of the anvils and the surface of the sample as a result of their “grabbing” (which causes deformation by torsion). Unlike the Cu sample, both on the upper and lower surfaces of the steel 10 disk after HPT with n = 5 revolutions densely spaced concentric circles-scratches of approximately the same intensity are observed. The scratches presumably formed in the similar way as a result of the incompatible movement of the anvils along both the upper and lower surfaces of the disk (sliding of the anvils along the surface). It is possible that sliding occurs first on one surface, then on the other one, since in the total sliding mode, sliding between the upper and lower surfaces may occur randomly.