The Ti-18Zr-15Nb shape memory alloys are a new material for medical implants. The regularities of phase transformations during heating of this alloy in the coarse-grained quenched state and the nanostructured state after high-pressure torsion have been studied. The specimens in quenched state (Q) and HPT state were annealed at 300–550 °C for 0.5, 3, and 12 h. The α-phase formation in Ti-18Zr-15Nb alloy occurs by C-shaped kinetics with a pronounced peak near 400–450 °C for Q state and near 350–450 °C for HPT state, and stops or slows down at higher and lower annealing temperatures. The formation of a nanostructured state in the Ti-18Zr-15Nb alloy as a result of HPT suppresses the β→ω phase transformation during low-temperature annealing (300–350 °C), but activates the β→α phase transformation. In the Q-state the α-phase during annealing at 450–500 °C is formed in the form of plates with a length of tens of microns. The α-phase formed during annealing of nanostructured specimens has the appearance of nanosized particle-grains of predominantly equiaxed shape, distributed between the nanograins of β-phase. The changes in microhardness during annealing of Q-specimens correlate with changes in phase composition during aging.

The development of high-performance biodegradable alloys with controllable corrosion rates to be used for manufacturing advanced implants is a hot topic of modern materials science and biomedicine. This work features the changes in microstructure, corrosion behavior and mechanical properties of the Mg-2 wt.%Sr alloy progressively induced by equal-channel angular pressing, high-pressure torsion and annealing. We show that such processing leads to significant microstructure refinement including diminishing grain size, defect accumulation and fragmentation of the initial eutectics. We demonstrate that the application of severe plastic deformation and heat treatment is capable of considerably enhancing the mechanical and corrosion performance of a biodegradable alloy of the Mg-Sr system. The best trade-off between strength, plasticity and the corrosion resistance has been achieved by annealing of the Mg-Sr alloy subjected to combined severe plastic deformation processing.

It is known, that magnesium-based alloys are the appropriate materials to be used as biodegradable metals to produce new-generation medical implants. Magnesium can decompose in the human body during the healing process. If dissolution is controlled, there is no need in additional operation for implant removal after healing completion. Particularly, Mg-Zn-Ca alloys are considered the most appropriate biodegradable metal implants due to their biocompatibility. In the Mg-Zn-Ca alloys, the addition of Zn and Ca as alloying elements can improve the mechanical properties and increase the corrosion resistance compared to pure Mg without affecting biocompatibility. The work covers the study of the structure and mechanical properties of the magnesium Mg-1%Zn-0.2%Ca alloy after severe plastic deformation (SPD). The research of the structure was carried out using scanning and transmission electron microscopy. The study of mechanical properties was carried out by measuring microhardness and tension tests. The study shows that applying the equal channel angular pressing (ECAP) method and additional treatment with the severe plastic deformation (SPD) method to the Mg–1%Zn–0.2%Ca alloy leads to the formation of the ultra-fine grain (UFG) structure with the average grain size of less than 1 micron. The authors identified that, as a result of strong refinement of the magnesium alloy grain structure, the ultimate strength increases twice up to 283 MPa compared to the homogenized state, when the ultimate strength is 125 MPa. At the same time, in the UFG state, the plasticity significantly decreases up to 3 %.

Zinc biodegradable alloys are actively researched as promising materials for creating biomedical implants for osteosynthesis and vascular stents. New zinc alloys of the Zn–Ag–Cu system are of particular interest due to their antimicrobial and bactericidal properties conferred by the addition of silver and copper. The feasibility of producing a defect-free zinc alloy spoke and the influence of combined processing, involving severe plastic deformation techniques, such as equal-channel angular pressing (ECAP) and extrusion, on the microstructural changes and mechanical properties of the Zn 1 wt % Ag 1 wt % Cu (Zn–1Ag–1Cu) alloy were studied. To complement the experimental study, computer modeling of the extrusion of the Zn–1Ag–1Cu alloy at a temperature of 150°C was performed. Data on the distribution of accumulated deformation and average stresses were obtained, indicating structural relaxation. Multipass ECAP treatment resulted in a significant grain refinement to 3 ± 0.5 μm compared to the homogenized state with a grain size of 326 ± 31 μm, while subsequent extrusion led to recrystallization. After combined processing, the average grain size increased to 13 ± 2 μm. Samples subjected to ECAP exhibited a substantial increase in ultimate strength to 204 MPa and ductility to 50%, compared to the homogenized state (78 MPa, 12%). However, extruded samples showed a slight decrease in strength to 181 MPa and ductility to 29%. It was concluded that the combined deformation techniques enable the production of a defect-free spoke with a diameter of 5 mm and a length of 200 mm, exhibiting mechanical properties suitable for medical applications.

Currently, scientists search for new materials for temporary implants that can dissolve in the body, which leads to the fact that there is no need for repeated surgery. In the last decade, scientific interest has focused on zinc-based materials because, unlike other metals, it has suitable corrosion rates and good biocompatibility. The paper describes an experiment for the study of the influence of deformation on the microstructure, strength and corrosion properties of an alloy of the Zn–Fe–Mg system. The authors carried out energy dispersive analysis and calculation of the volume fraction of the second phase of the Zn–Fe–Mg zinc alloy. The corrosion properties of the Zn–Fe–Mg zinc alloy with different microstructures (before and after high-pressure torsion) were studied using the gravimetric method under conditions simulating conditions inside a living organism (temperature, corrosive environment composition). During the tests, the corrosion mechanism was determined, its rate and mass loss of the samples were calculated. The relief of the corrosion surface was studied using scanning electron microscopy. It has been found that the destruction of the material in a corrosive environment occurs through a matrix containing the active Mg metal. The results of calculations of the corrosion rate for the original sample and samples subjected to high-pressure torsion differed due to a more even distribution of second phase particles during severe plastic deformation. In this work, by alloying zinc with iron and magnesium, as well as using high-pressure torsion, it was possible to increase the microhardness of the samples to 239.6±8 HV, which is a high indicator for zinc alloys.