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

Studies of the impact of high voltage electric discharge (HVED) treatment on the dispersion and phase composition of 87,5 % Al + 12,5 % Cu powder system were performed. It was shown that HVED treatment in ethanol with specific treatment energy of 5 MJ/kg leads to the decrease of mean diameter of treated powder from 15 to 11 μm, and the increase of specific treatment energy to 20 MJ/kg leads to the decrease of mean diameter of treated powder from 15 to 6 μm. X-ray diffraction analysis shows that CuAl2 and Al4C3 are synthesized in all considered treatment regimes, and the quantity of these phases depend on the specific treatment energy.
The use of “three point – plane” electrode system instead of “point – plane” during HVED treatment of 87,5 % Al + 12,5 % Cu powder system in ethanol leads to the increase of quantity of synthesized Al4C3 and CuAl2 phases with the slight decrease in the dispersion efficiency.
Up to 35% of particles in powder mixture, treated by HVED in ethanol with the use of “three point – plane” electrode system, have diameter close to the diameter of the initial powder mixture.
It is shown that the preparation of powders with an initial composition of 87.5% Al + 12.5% Cu using HVED treatment in kerosene or ethanol with subsequent consolidation by SPS method allows obtaining metal-matrix composites of the Al – Cu – C system with increased indicators of hardness, electrical conductivity and wear resistance.

This paper examines corrosion protection techniques for aluminum alloys, focusing on traditional and innovative surface treatment methods. Aluminum alloys are applicable in many industries due to their advantages derived from the good combination of chemical, physical, and mechanical properties. However, they are susceptible to various forms of corrosion, which can critically compromise the structure of the component and lead to damage that does not ensure safe operation. Coatings are necessary for the durability and effective protection of aluminum and its alloys from corrosion, ensuring safe and long-term operation of components in aggressive environments.

The phase and structure formation of aluminum-matrix composite materials reinforced with titanium carbide during their synthesis and consolidation using the forging were investigated. The influence of copper additives on the structure formation, density, porosity, and hardness of aluminum-matrix composites was determined. The research results revealed the presence of Al+Cu+TiC phases in copperalloyed samples. Studies of density and porosity showed that the samples without copper additives were maximally densified after hot stamping and had minimal porosity, unlike the copper-alloyed composites.

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 work shows that there is no significant change in the phase composition of composites with a change in the synthesis temperature, so we can use pre-synthesized heats at a temperature of 950 oC to obtain hot-stamped aluminum-based composites. The best characteristics of the synthesized titanium carbide were obtained for the composition 45Al-11C-44Ti (%, wt.). The lattice period of titanium carbide for this sample is 0.4324, and the particle size of titanium carbide formed after sintering is 0.8-1.5 μm. The influence of the component composition of the initial charge on the features of the structure and the phase composition of the thermally synthesized heat of the Al-C-Ti system was established.

This paper deals with the investigation of the effect of speed on the form fit joint of dissimilar materials. Thin -walled materials based on steel and aluminium alloy were joined by thermal drilling. The shape and size of the resulting bushing were evaluated. It turned out that the best material combination for joining by flowdrill technology are joints made of steel and aluminum alloy. Aluminum alloy must always be placed in the bottom position. The best parameters of the formed bushing were achieved with the combination of DC-Al or TL-Al materials, at tool speeds of at least 2400 rpm.

The paper focuses on the degradation of molds that are used for the technology of high-pressure casting of Al and its alloys. The method of high-pressure casting of aluminum products is one of the widely used production methods, which at the same time meets the requirements for precision and productivity in the production of cars and various mechanical parts. In the high-pressure casting process, the molds are exposed to various thermal and mechanical loads, where the molds and their shaped parts are degraded. The paper presents the results of research focused on the use of duplex PVD coatings to increase the life of shaped parts of molds for high-pressure casting of Al and its alloys.

Studies of the impact of high voltage electric discharge (HVED) treatment on the dispersion and phase composition of 87,5 % Al + 12,5 % Cu powder system were performed. It was shown that HVED treatment in kerosene with specific treatment energy of 5 MJ/kg leads to the decrease of mean diameter of treated powder from 15 to 13 μm, and the increase of specific treatment energy leads to the decrease of mean diameter of treated powder from 15 to 6 μm. X-ray diffraction analysis shows that CuAl2 and Al4C3 are synthesized in all considered treatment regimes.
HVED treatment with increased specific treatment energy leads to the increase of quantity of synthesized Al4C3 phase. The use of “three point – plane” electrode system instead of “point – plane” during HVED treatment of 87,5 % Al + 12,5 % Cu powder system leads to the increase of quantity of synthesized Al4C3 and CuAl2 phases, while the efficiency of powders dispersion slightly decreases. Up to 40% of particles in powder mixture, treated by HVED in kerosene with the use of “three point – plane” electrode system, have diameter close to the diameter of the initial powder mixture

The influence of Zn on the corrosion behavior of amorphous and nanosized rapidly solidified aluminum alloys (Al75Cu17Mg8)100-xZnx (x = 0; 1; 3) at. % and their crystalline analogues was studied. Data were obtained for resistance of basic and rapidly solidified aluminum alloys (Al75Cu17Mg8)100-xZnx (x = 0; 1; 3) at. % to uniform corrosion. It has been found that increasing the percentage of zinc increases the corrosion rate of both base alloys and rapidly solidified ribbons with similar composition. Pitting and intergranular corrosion tests have been performed. The parameters affected area, pitting density and pitting size were evaluated. An XRD analysis of the separated corrosion products was performed. It was found that the chemical composition, and not the amorphous microstructure of the ribbons, was of leading importance for the course of the corrosion process in the studied rapidly solidified ribbons (Al75Cu17Mg8)100-xZnx and base alloys.

This paper presents new methods of thermal processing of the aluminum alloys. It analyses the effects of boiling treatment of alloys Al–Cu and Al–Si in an oxidizing atmosphere on their microstructure, hydrogen content and the coefficient of linear thermal expansion (CLE). An increase of boiling time from 15 to 75 hours results in an initial increase in the hydrogen content in alloys later followed by a decline in the hydrogen content. These changes in the hydrogen content correlate with the dynamics of alloys’ microstructure and their CLE. This study shows that atmosphere with a high oxygen content induces an acceleration of diffusion processes in aluminum alloys. If boiling time does not exceed 30 hours, the hydrogen content in a solid solution and etchability of grain boundaries of α-solid solution decrease and intermediate phases get partially dissolved. We demonstrate that boiling treatment of aluminum alloys in an oxidizing atmosphere leads to a decline of the CLE measured under the temperature 50-450°С which is especially strong when measured under the temperature 250-350°С.