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

ECAP was carried out with a gradual decrease in temperature and an increase in the number of passes on two medical magnesium alloys: WE43 (Mg-3.56%Y-2.20%Nd-0.47%Zr) and ZX10 (Mg-1.0%Zn-0.3%Ca). It was shown that ECAP leads to a significant refinement of the alloys structure. For ZX10 alloy, the average grain size after ECAP decreased from ~ 105 μm in the initial state to 8 ± 0.18 μm in the longitudinal section and to 4 ± 0.19 μm in the transverse one. For the WE43 alloy, the average grain size was changed from 70 μm to 0.69 ± 0.13 μm and the precipitation of particles of the Mg41Nd5 phase with an average size of 0.45 ± 0.18 μm was also discovered. At the same time, the grain refinement led to an increase in the strength characteristics of the both alloys (including fatigue strength), and increased prismatic slip activity (along with the formation of an inclined basal texture in ZX10 alloy) led to an increase in their ductility. The alloy structure formed during the ECAP process does not lead to a decreasing in resistance to chemical corrosion.

The research paper presents the improvement on the mechanical and service properties of the austenitic stainless 0.07% C-17% Cr-9% Ni-0.7%-Ti steel in the fully austenitic state obtained by equal-channel angular pressing (ECAP) at the temperatures of 200 °C and 400 °C. Subgrain oriented structure in the Cr-Ni-Ti steel after ECAP significantly enhances the strength characteristics of steel at satisfactory plasticity. The fatigue limit of steel after ECAP at T = 200 ° C is higher than that after ECAP at T = 400 ° C, increasing in comparison with the initial state by 2.2 and 1.7 times, respectively. It was revealed that severe plastic deformation by ECAP increases the friction coefficient of the material by the 1.1 and 1.7 times at T = 200 ° C and 400 ° C, respectively. Despite this, the wear rate after ECAP at T = 200 ° C and 400 ° C decreases by 7 and 40 times, respectively, compared to initial state.

Structure and properties of low-alloyed copper-based alloys with Cr, Zr and Hf after severe plastic deformation (SPD) using techniques of high pressure torsion (HPT) and equal channel angular pressing (ECAP) have been studied. SPD significantly increases strength of the alloys by formation of ultrafine-grained structure. Cu5Zr and Cu5Hf particles suppress the grain growth in ultrafine-grained (UFG) structure more effectively than the Cr particles and provide additional hardening during aging. Moreover, it was found that the application of additional aging after SPD significantly improves service properties of the alloys (fatigue limit, wear resistance and electrical conductivity). This combination of properties results in a high durability of electrodes for resistance spot welding produced from UFG Cubased alloys.