Sergey Viktorovich Konushkin

The research described in this article is a continuation of a series of studies on biocompatible materials, focused on finding the optimal alloy composition and heat treatment regimes. The use of materials with a low Young’s modulus ensures the long-term safety of the implant by reducing the stress shielding effect, which causes bone resorption. This work investigates the effect of alloying with niobium in the range of (8–10) at. % on the Ti-38Zr alloy, specifically its structure, mechanical properties, Young’s modulus, and superelasticity. In this study, plates of the Ti-38Zr-(8-10)Nb (at. %) alloy were investigated after quenching and subsequent annealing. In Ti-38Zr-(8-10)Nb alloys, quenching from 600 °C fixes the β-phase of Ti. In alloys with (8-9)Nb, this is a metastable β-phase, as evidenced by its superelastic behavior under cyclic tension. Annealing at 400 °C leads to a clear decomposition of the quenched high-temperature β-phase in Ti-38Zr-(8-9)Nb alloys into β- and α′-phases. Based on the mechanical test results, it can be inferred that the precipitation of the brittle ω-phase and the α′-phase occur concurrently, since annealing at 400 °C causes a pronounced embrittlement of the Ti-38Zr-(8–9)Nb alloys (with elongation dropping from ~15% to 0.7–2.5%, respectively) alongside a substantial increase in strength (from 500 MPa to 1010 MPa). For the Ti-38Zr-10Nb alloy, the ductility also declines but remains within acceptable limits (from ~14% to ~10%), while the strength rises from 520 MPa to 630 MPa. The Young’s modulus of the Ti-38Zr-(8-10)Nb alloy after quenching is ~80 GPa. After annealing, it increases to 95 GPa for alloys with (8-9)Nb, while for 10Nb it remains at approximately 80 GPa.

In today's world, environmental issues are becoming more and more pressing. The manufacture of structural materials such as metals, concrete, ceramics, and composites has a considerable impact on the environment. Therefore, the development and improvement of methods that minimize the adverse environmental impact and design of more sustainable production processes are fairly relevant. Currently, the concept of nature-inspired materials has been elaborated. A number of such materials have been already developed and some are being developed now. This review addresses, for the first time, the current state of research in the development of nature-inspired and safe materials based on titanium alloys and steels. The bibliography includes 144 references.

Hip joint implants are among the most prevalent types of medical implants utilized for the replacement of damaged joints. The utilization of modern implant materials, such as cobalt–chromium alloys, stainless steel, titanium, and other titanium alloys, is accompanied by challenges, including the toxicity of certain elements (e.g., aluminum, vanadium, nickel) and excessive Young’s modulus, which adversely impact biomechanical compatibility. A mismatch between the stiffness of the implant material and the bone tissue, known as stress shielding, can lead to adverse outcomes such as bone resorption and implant loosening. Recent studies have shifted the focus to β-titanium alloys due to their exceptional biocompatibility, corrosion resistance, and low Young’s modulus, which is close to the Young’s modulus of bone tissue (10–30 GPa). In this study, the microstructure, mechanical properties, and phase stability of the Ti-38Zr-11Nb alloy were investigated. Energy dispersion spectrometry was employed to confirm the homogeneous distribution of Ti, Zr, and Nb in the alloy. A subsequent microstructural analysis revealed the presence of elongated β-grains subsequent to rolling and quenching. Furthermore, grinding contributed to the process of recrystallization and the formation of subgrains. X-ray diffraction analysis confirmed the presence of a stable β-phase under any heat treatment conditions, which can be explained by the use of Nb as a β-stabilizer and Zr as a neutral element with a weak β-stabilizing effect in the presence of other β-stabilizers. Furthermore, the modulus of elasticity, as determined by tensile testing, exhibited a decline from 85 GPa to 81 GPa after annealing. Mechanical tests demonstrated a substantial enhancement in tensile strength (from 529 MPa to 628 MPa) concurrent with a 32% reduction in elongation to fracture of the samples. These alterations are attributed to microstructural transformations, including the formation of subgrains and the rearrangement of dislocations. This study’s findings suggest that the Ti-38Zr-11Nb alloy has potential as a material of choice due to its lower Young’s modulus compared to traditional materials and its stable β-phase, which enhances the implant’s durability and reduces the risk of brittle phases forming over time. This study demonstrates that the corrosion resistance of titanium grade 2 and Ti-38Zr-11Nb is comparable. The material in question exhibited no evidence of cytotoxic activity in the context of mammalian cells.

Influence of six types of blasting and electrolytic-plasma polishing on the surface roughness and wettability and interaction with the bacterium Escherichia coli of two commercial titanium-based alloys used in medicine, VT1-0 (pure titanium) and VT6 (titanium alloy with aluminum and vanadium), as well as the Ti–Nb–Zr alloy being developed at the Baikov Institute of Metallurgy and Materials Science of the Russian Academy of Sciences (IMET RAS), was studied. It was noted that all the obtained surfaces are wettable; the wetting angle is naturally the higher, the lower the surface roughness; however, in the case of all materials after sand blasting with mixtures with a wide range of particle sizes, an increase in the wetting angle is noted. All metal samples do not have antibacterial activity and do not contribute to the formation of a sterile zone. The ability to form biofilms from the bacterium E. coli on the surface of metals was studied. It was shown that their number is significantly less in the presence of samples compared to the control. The developed Ti–Nb–Zr alloy, which potentially has better biomechanical compatibility than the commercial ones used, showed no deterioration in surface characteristics and no effect on bacterial growth.

Hip joint implants are one of the most common types of medical implants used to replace a damaged joint and restore its functional activity. Hundreds of thousands of surgeries are performed annually to install them, which underscores the importance of developing and improving materials for such implants. Modern materials for implants, including co-balt-chromium alloys, stainless steel, titanium and other titanium alloys, face problems such as the toxicity of certain elements (for example, aluminum, vanadium, nickel) and excessive Young's modulus, which negatively affects biomechanical compatibility. A mismatch between the stiffness of the implant material and the bone tissue, called stress shielding, can lead to bone resorption and loosening of the implant. Recent studies have shifted the focus to β-titanium alloys due to their exceptional biocompatibility, corrosion resistance, and low Young's modulus, which is close to the Young's modulus of bone tis-sue (10-30 GPa). Among them, Ti-38Zr-11Nb alloy is promising for use as an implant material. In this study, the microstructure, mechanical properties, and phase stability of Ti-38Zr-11Nb alloy were studied. Energy dispersion spectrometry confirmed the homo-geneous distribution of Ti, Zr, and Nb in the alloy. Microstructural analysis revealed elongated β-grains after rolling and quenching, and grinding contributed to recrystalliza-tion and the formation of subgrains. X-ray diffraction analysis confirmed the presence of a stable β-phase under any heat treatment conditions, which is explained by the use of Nb as a β-stabilizer and Zr as a neutral element with a weak β-stabilizing effect in the pres-ence of other β-stabilizers. The modulus of elasticity after annealing decreased from 85 GPa to 81 GPa. Mechanical tests showed a significant increase in tensile strength (from 529 MPa to 628 MPa) simultaneously with a 32% decrease in elongation to fracture of the samples. These changes are caused by microstructural transformations such as the for-mation of subgrains and rearrangement of dislocations. Based on the results of the study, it can be concluded that Ti-38Zr-11Nb alloy is a promising material due to its lower low Young's modulus relative to the classical materials used and stable β-phase, which pro-vides the possibility of long-term use of the implant, without the risk of formation of brittle phases.

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The work described in this article is aimed at investigating the properties of a group of Ti-Zr-Nb alloys. In modern orthopedics and traumatology, the use of materials for bone implants with a minimum modulus of elasticity is becoming increasingly important. This is due to a number of advantages that allow for better integration of the implants with the bone tissue, including the reduction in the detrimental effect of the load-shielding effect, a better load distribution, and stress distribution, which allows for increasing the life of the implant. It is known that the lowest modulus of elasticity in titanium alloys at normal temperature is achieved by the phase composition consisting of metastable β-phase. It is possible to achieve the desired structure by a combination of alloy composition selection and heat treatment. Quenching of titanium alloys allows for the high-temperature β-phase to be fixed. This paper provides justification of the choice of compositions of the studied alloys by calculation methods. The structure of alloys after melting in a vacuum electric arc furnace in an argon environment was studied. The ingots obtained had a dendritic structure. Homogenizing annealing in a vacuum furnace at 1000 °C for 4 h was used to equalize the composition. The structure of the alloyed sheets after hot rolling and hot rolling and quenching was investigated. The microstructure of the plates in both variants had uniform grains of polyhedral shape. X-ray phase analysis of the plates showed that the content of metastable β-phase was 100% before and after quenching. Microhardness testing of the plates showed no significant effect of quenching. The result of the mechanical properties study showed an increase in the plasticity of the material after quenching, with the tensile plots of the samples after quenching reflecting the area where the reverse phase transition of β’<-> α’’ occurs. Mechanical studies by cyclic loading showed the presence of a superelasticity effect. The Young’s modulus study gave a result of 51 GPa for one of the compositions studied. The combination of properties of the materials under investigation has the potential for promising use as a basis for bone implants.

Types of Construction Nails from Markul, Abkhazia (Based on Metallographic Analysis)

The influence of fillers on the structures of siloxane films is studied. Three versions of fillers are considered: ethyl alcohol, chitosan, and sodium bicarbonate with its subsequent removal. It is shown that the use of alcohol leads to a change in the surface structure and formation of numerous “pit” pores. The use of sodium bicarbonate or chitosan as fillers makes it possible to create developed networks of pores intersecting with each other and having access to the surface. The possibility of controlling the thickness of porous layers by varying the concentration of the introduced filler is shown. A conclusion is drawn that the studied versions of modification of the structure of siloxane films open up wide opportunities for creating drug delivery systems or other active agents, including those with controlled prolonged action.