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

The paper presents the results of studies of tribological properties of the contact of the tool steel composition Fe-18W-4Cr-1,2V with the magnesium alloy AZ91D strengthened by submicron powder filling out of SiC and severe plastic deformation (SPD), namely equalchannel angular pressing (ECAP). It is stated that introduction of SiC powder filling to the magnesium alloy the friction coefficient on the moving frictional contact increases, the wear rate reduces. These tribotecnical characteristics are influenced by the size and volume of the particles of powder filling, normal loading force and slip rate. SPD of the initial material results in reduction of the adhesion constituent of the friction coefficient.

In this paper, we present the results of the tribological studies of commercially pure copper (99.9% Cu) and a low-alloyed chromium bronze (Cu-0.5%Cr), contacting a graphite-containing material. The samples under study were produced with two types of microstructures: a coarse-grained (CG) one, having an average grain size of 100-130 μm after annealing, and a submicrocrystalline (SMC) one, having an average grain size of 0.30-0.50 μm after multi-cycle severe plastic deformation (SPD) processing via equal-channel anglar pressing (ECAP) combined with Conform. It is shown that for the samples produced by ECAP-Conform, having an SMC structure, the friction coefficients are 12 – 20% lower than for the as-annealed samples, having a CG structure.

The information is given about small-sized equipment for producing sprayed powders of alloys based on copper and aluminum, intended for strengthening new and restoring worn-out surfaces by applying a gas-flame coating, as well as for the protection of parts against corrosion, process modes and powder properties. The high quality of the coatings obtained with the use of manufactured powders has been confirmed.

The paper presents experimental data on the tribological properties of commercially pure titanium with different microstructures with and without coating. As a result of the conducted experiments, it was established that the integral value of the friction coefficient, as well as its adhesion component, are structurally sensitive parameters. It is noted that the ultrafine-grained structure, obtained as a result of intense plastic deformation, contributes to the reduction of the coefficient of friction, as well as to the increase of the load-bearing capacity of tribo-conjugation.

With the help of computer simulation in the DEFORM-3D software, there was performed a virtual full factorial experiment of the process of shear drawing. In the course of the experiment, the effect of independent parameters (drawing speed, die rotation rate, die angle and friction factor) on the strain intensity was evaluated. As a result of the experiment, a regression equation was derived and the most significant individual factors and their combinations, influencing the response parameters, were determined. Also, comparative results were presented for the processes of regular drawing and shear drawing. It was demonstrated that the process of shear drawing has a higher efficiency from the point of view of strain intensity.

This paper presents the results of preliminary corrosion tests of samples from commercially pure titanium Grade 4 with a coarse- grained (annealed) and ultrafine-grained structure after severe plastic deformation, as well as of samples processed by microarc oxidation and with an ion-plasma coating. The effect of microstructure on the corrosion of the material under study is shown. A comparative evaluation of the corrosion rate is performed.

The conditions are substantiated for the loss of thermodynamic stability of a tribosystem and for its adaptation with a decreasing wear rate at the moving frictional contact of parts from materials with an ultrafine-grained structure produced by equal-channel angular pressing. The regularities of the influence of the structure’s dispersion degree and the friction contact’s temperature on the tribotechnical characteristics of ultrafine-grained materials are established theoretically and experimentally.

This work presented the results of tribological studies of commercially pure copper (Cu 99.9%) and low-alloyed chrome bronze Cu-1%Cr in contact with a graphitiferous plate EK-40. Samples from copper and copper alloy were prepared to obtain two kinds of grain size of microstructure. Two schemes were used for tribological studies. The first scheme was used during reciprocal movement to evaluate the friction coefficient. The second scheme was employed to evaluate the shear strength of adhesive bonds and the adhesive component of the friction coefficient.Besides, the fulfilled studies determined that the tribological properties of materials depended on the grain size of microstructure. It is shown that an ECAP–Conformed specimen with UFG exhibits 20-30% lower friction coefficients than that of annealed specimen with CG structure. The tribological test results showed that the coefficient of friction decreased, with the decreasing grain size. Therefore, were conclude the coefficient of friction of proposed materials is microstructure-sensitive.

The effect of severe plastic deformation on the kinetics of second phases in a dispersion-strengthening Cu-Cr-Zr alloy is investigated. The observed set of phenomena indicates that during SPD processing there occurs a complex interaction between deformation mechanisms and the processes of dissolution and precipitation of second-phase particles in the copper matrix, influencing structure refinement and resulting in a change of the particle sizes and their distribution, and consequently, the material’s strength.

This paper reports on the results of corrosion tests, using alternative methods, of Grade 4 CP Ti samples with coarse-grained (annealed) and ultrafine-grained structures after severe plastic deformation processing. The effect of microstructure on the corrosion of the material under study is demonstrated. It is revealed that the material with a UFG structure has a higher corrosion resistance, as compared to the samples with a CG structure.

The paper presents the results of numerical modeling of the conventional drawing and free torsion processes of rods made of low-carbon steel using the "DEFORM-3D" software package. The heterogeneity of the strain intensity distribution in the investigated processes revealed in the model basically corresponds to real physical experiments with similar parameters of the structural heterogeneity. A mutual correspondence of the ductility diagram to the character of the structural changes in the samples deformed by free torsion is established, and the limiting values of the ductility margin, the excess of which leads to the development of fracture processes.

This paper reports on the results of corrosion tests, using alternative methods, of Grade 4 CP Ti samples with coarse-grained (annealed) and ultrafine-grained structures after severe plastic deformation processing. The effect of microstructure on the corrosion of the material under study is demonstrated. It is revealed that the material with a UFG structure has a higher corrosion resistance, as compared to the samples with a CG structure.