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

This study presents a theoretical investigation of the densification kinetics of titanium powder during electro-pulse consolidation. A mathematical model was developed to analyze the influence of electrical current parameters in different sintering regimes – direct current (DC), alternating current (AC), pulsed current, and their superposition – on the thermophysical processes governing sintering.
The heating rates and the evolution of relative density were calculated for different applied pressing pressures. The results show that the superposition of currents is the most energy-efficient regime. This regime enables the material to reach a relative density above 99% within a minimal processing time. The effect is attributed to the combined action of intense Joule heating and the electroplastic effect.

A novel two-stage approach for obtaining wear-resistant multifunctional powder composites based on metal powders with highmodulus Ti–TiC system fillers is proposed. The method combines high-voltage electric discharge (HVED) treatment and spark plasma sintering (SPS), offering a promising alternative to conventional techniques for producing Al–Ti–C system composites. This approach enables the development of a unified route for material synthesis using high-energy-density processing. HVED treatment prevents oxidation of metal particles, reduces contamination by tool materials, and initiates the synthesis of additional dispersed strengthening phases. For example, HVED treatment of titanium powder in a hydrocarbon liquid promotes the in situ formation of titanium carbide (TiC) particles.
The present work investigates the influence of adding Ti–TiC powder—synthesized via HVED in ethanol under reverse polarity mode with a specific energy input of 20 MJ/kg—on the structure, phase composition, and properties of Al–Ti–C metal matrix composites (MMCs). It was shown that the addition of 2 wt% of Ti–TiC powder synthesized via HVED in ethanol to aluminum powder results in an MMC with an electrical resistivity of 0.5 Ω·mm²/m and a hardness of 31 HRB. However, the heat resistance of this composite is 2.5 times lower than that of consolidated pure aluminum powder. Increasing the Ti–TiC content to 10 wt% leads to the formation of a wear-resistant Al–Ti–C composite, whose structure includes Al, Ti, TiC, the intermetallic compound Al₃ Ti, MAX phases Ti₂ AlC and Ti₃ AlC₂ , and free carbon. For the MMC sample with the addition of 10% Ti–TiC, the mass gain per cycle during the heat resistance test is 0.23%/cycle, whereas for samples made from consolidated Al powder it is 0.18%/cycle, indicating that their heat resistance is approximately the same. The wear resistance of this composite is more than three times higher than that of the consolidated base aluminum powder, with wear rates of 0.003 g/km and 0.010 g/km, respectively. This material also demonstrates a hardness of 43 HRB and relatively low electrical resistivity at the level of 0.3 Ω·mm²/m.

High-voltage electrical discharge (HVED) treatment of powder mixtures is a modern, efficient, and economically advantageous method for both particle size reduction and modification of the material’s phase composition. The primary mechanisms of particle destruction within the discharge zone include shock waves, microcavitation, ablation, collisions with chamber components, and mutual abrasion between particles.
The application of machine learning methods to model HVED processes for titanium—a promising material for composite applications— enables more accurate predictions and optimization of the technological workflow.
The data used for modeling were obtained between 2013 and 2021 and include results from the treatment of the initial titanium powder (with an average diameter of d₀ = 60 μm) in ethanol. This setup enabled the formation of a volume-distributed multi-spark discharge (VMD) within the ethanol–powder dispersed system. The dataset includes information on the number of treatment pulses, discharge gap, pressure in the discharge channels, pressure on the chamber walls, and the amount of titanium carbide formed during the treatment process.
It was shown that the concentration of TiC gradually rises with the increase of specific treatment energy, regardless of the interelectrode gap. Specifically, at a specific energy (Ws) of 5 to 15 MJ/kg, the amount of titanium carbide reaches 10%; at 15 to 30 MJ/kg, it increases to 20%; and at energy levels above 30 MJ/kg, the TiC content reaches 30%.
Keywords: Ethanol, Titanium, Titanium Carbide, High-Voltage Electrical Discharge, Volume-Distributed Multispark Discharge, Electric Discharge Dispersion, Plasma Technologies, Machine Learning, Logistic Regression, Random Forest

The results of a quantitative study of the influence of methods of chemical cleaning, pulse treatment with high-voltage electric discharges in a liquid, and flotation separation of synthetic diamond powder of the AS20 grade with a grain size of 100/80 on its abrasiveness are given. It has been established that the use of pulse treatment with high-voltage electric discharges in a liquid provides selective destruction of low-strength diamond particles, activation of the energy state of the surface, and an increase in abrasiveness. Changes in powder characteristics: homogeneity in strength by 1.3-1.9 times; decrease in the mass fraction of impurities by 2.8-7.8 times; guarantee an increase in abrasiveness up to 30-34% and contribute to the improvement of the physico-mechanical and physico-chemical characteristics of synthetic diamond powder

The results of studies of the behavior of rocks with fluids under impulse pressure, which is induced by an electric discharge in solutions of surface-active substances (surfactants), are given. The mechanism of influence of high-voltage electric discharges and mechanical waves induced by them on the behavior of combined objects (porous rocks, hydrocarbon fluids filling their pores – oil and hydrogen surfactant solution, solid mineral sediment) is revealed.
It was found out that the use of a water-oil emulsion as a working medium for high-voltage electric discharge significantly (2 times for sandstones and 1.5 times for carbonates) increases the efficiency of the electric discharge effect compared to water.
The complex action of the electric discharge and the aqueous 0.3% solution of NMK-21, used as a working medium, leads to a synergistic effect in increasing the permeability of rocks by twice the sum of the effects for each component.
Work results can be used in the development of scientific foundations of managing the filtration properties of porous materials of various origins.

Physical modeling of processes in a layer of Al powder in kerosene and ethyl alcohol during high-voltage electrical discharges in the spark discharge mode was carried out. The regularities of the distribution of plasma formations in the volume of the discharge chamber were studied when using ethyl alcohol and kerosene as working substances with an increase in the number of discharges. It is shown that the use of kerosene as a working fluid leads to an increase in the intensity of the formation of discharges between particles. It has been established that ethyl alcohol as a working fluid makes it possible to relatively stabilize the discharge mode, as well as to increase the number of discharges before the appearance of visual signs of the presence of residual nanocarbon, as a result of which it is possible to achieve greater dispersion of the processed powders. The possibility of synthesis of submicron and ultradisperse particles during highvoltage electric discharge processing of aluminum powder in a hydrocarbon liquid (alcohol or kerosene) due to the electrothermal effect of the discharge plasma on the powder particles has been confirmed.

The possibility of using machine learning methods to predict the results of high-voltage electric discharge treatment of titanium powder in a hydrocarbon liquid is studied. As a result of the work, distribution surfaces for the average particle diameter of Titanium powder. the amount of Titanium carbide formed during processing, and the number of spherical particles of titanium powder depending on the interelectrode gap and the number of pulses, when using spark discharge and with Titanium powder concentration in kerosene of 0.07 kg / dm3, pulse repetition frequency 0.3 Hz and the energy of single discharge of 1 kJ, were obtained.