Nowadays, there is a great demand for increasing the strength and corrosion resistance of magnesium alloys for their wider use in machine engineering, oil industry, and medicine. This paper is devoted to a study on the effects of the combined process of reduction and equal channel angular pressing, as well as the subsequent ultrasonic irradiation on the structure, strength, and corrosion properties of the Mg-Al-Zn alloy. Deformation processing results in an increase of the strength up to 280 ± 10 MPa. A fine-grained structure is formed with a grain size of 10–20 µm and small recrystallized grains 1–2 µm in size. The corrosion resistance in the HCl medium falls down significantly. Action of ultrasound on the deformed specimen leads to an increased fraction of high-angle boundaries, in particular, the fractions of special, fully overlapping Σ13a boundaries and twin boundaries of Σ15b and Σ17a systems. Due to the ultrasonic treatment, the strength of the Mg-Al-Zn alloy increases up to 310 ± 5 MPa, while the corrosion resistance in HCl almost doubles.

The quantitative concentration of alloying elements in low-alloyed copper alloys is an important factor in forming electrical and mechanical characteristics. It is known that severe plastic deformation is accompanied by both a substantial refinement of the structure and changes in the kinetics of phase transformations during the deformation and the post-deformation thermal treatment. This paper presents the results of a comparative analysis of the Cu–0.2Cr and Cu–1.1Cr alloys subjected to equal-channel angular pressing at room temperature. The analysis was performed for the grain structure, solid solution, and second-phase particles using transmission electron microscopy, scanning electron microscopy, X-ray crystal analysis, and the small-angle diffraction method. It was found that the level of structure refinement and mechanical characteristics after equal-channel angular pressing was almost the same for both studied alloys. Post-deformation aging of the Cu–0.2Cr alloy leads to the development of polygonization and re-crystallization within it. The aging of the Cu–1.1Cr alloy shows a better thermal stability than that of the Cu–0.2Cr alloy. In the Cu–1.1Cr alloy, after aging, in comparison with Cu–0.2Cr, a denser-packed ensemble of fine particles with an average size of 54 ± 2 nm is formed. In this case, the average size of fragments is 270 ± 15 nm and the ultimate tensile strength reaches 485 MPa.

Magnesium alloys are considered promising materials for the production of bioresorbable implants. Their main disadvantages are low strength and corrosion resistance in biological environment. In the work, the authors studied the effect of severe plastic deformation using the equal channel angular pressing (ECAP) method on the structure, mechanical properties, and corrosion resistance of the Mg–8.6Zn–1.2Zr magnesium alloy. It was identified that one ECAP cycle at 400 °C leads to a substantial hardening of the Mg–8.6Zn–1.2Zr alloy by ~10 %, up to 330 MPa. Structural studies showed that dynamic recrystallisation plays a significant role in the structure transformation. ECAP leads to the formation of a bimodal structure with large deformed grains with an average transverse size of 20±4 µm and recrystallised grains with an average transverse size of 6±2 µm. It was found that with a decrease in the strain temperature up to 250 °С, the process of deformation-induced decay of the supersaturated solid solution takes place. Electrical conductivity of a sample after ECAP at 400 °C amounted 29±2 % according to the International Annealed Copper Standard (IACS), while second ECAP cycles lead to an increase in the electrical conductivity up to 32±2 % IACS. Using the electrochemical corrosion method, the authors found that one ECAP cycle at 400 °C leads to a slight decrease in the corrosion resistance of the alloy under study compared to the initial state. The study showed that the corrosion current increases from 24 to 32 µA/cm2, while the subsequent ECAP cycle at 250 °С increases the corrosion current more than twice (up to 57 µA/cm2).

One of the current tasks of materials science is to increase the fatigue resistance of materials used in the creation of promising and modern implant designs. I

In this paper, the effect of deformation by equal-channel angular pressing (ECAP) and subsequent coating formation using various regimes (pulsed unipolar polarization—PUP and pulsed bipolar polarization—PBP) of plasma electrolytic oxidation (PEO) on the corrosion behavior of a bioresorbable Mg–Zn–Zr magnesium alloy was studied. Structural studies, gravimetric and electrochemical corrosion tests were performed to evaluate the alloy’s resistance to corrosion in Ringer’s solution. It was found that the use of ECAP contributes to structure refinement and a decrease in the corrosion rate, as compared to the initial state, to 7.6 ± 0.7 mm/year. The best corrosion resistance of the alloy in both the initial and deformed states is ensured by applying the PEO coating using the PUP regime; the corrosion rate was 2.8 ± 0.2 and 3.8 ± 0.4 mm/year, respectively. This may be due to the fact that this regime exhibits a higher content of the high-temperature forsterite Mg₂SiO₄ phase_. Electrochemical tests indicate a decrease in the corrosion current density for the PEO-coated samples by 3–4 orders of magnitude. ECAP processing leads to an increase in the polarization resistance to corrosion for the samples with a PEO coating produced in the PUP and PBP regimes.