Materials science

Tribotechnical properties of intermetallic coatings of the ti-al system produced by ion-plasma treatment of aluminium coating on titanium alloy Ti-6Al-4V

A.A. Nikolaev, K.N. Ramazanov, A.Yu. Nazarov, V.R. Mukhamadeev, K.A. Reunova, E.G. Astafurova

We study the tribological properties of intermetallic coatings of the Ti-Al system obtained by ion-plasma treatment of an aluminum coating on a Ti-6Al-4V alloy. It has been established that a decrease in the thickness of the initial aluminum coating from 2.5µm to 0.5µm reduces the fraction of the TiAl₃ phase in the resulted coating. This promotes the formation of hardened layers, which consist mainly of the TiAl phase and the Ti(Al) solid solution and provide high wear resistance of the coated Ti-6Al-4V alloy.

Keywords: titanium alloy, ion-plasma processing, intermetallic compounds, tribological properties.

The influence of the initial structure of a semi-finished product and aging modes on the shape recovery temperatures of alloys based on titanium nickelide

M.Yu. Kollerov, E.A. Lukina, A.O. Snegirev, O.S. Alsaeva

The initial structure and aging regimes should be taken into account for the temperature and deformation characteristics of the alloy based on titanium nickelide. It is shown that the most frequent processes of decomposition of the B2 phase with the formation of nickel-rich intermetallic compounds occur at an aging temperature of 430–460°C, causing an increase in the shape recovery temperature by more than 50°C. A high concentration of defects in the crystal structure of the B2-phase of the sample in the initial rolled state accelerates the processes of its structure and a higher shape recovery temperature. The results of the experiments are summarized in the form of diagrams that establish the relationship between the temperature-time conditions of aging and the temperature forms of the forms, which are convenient to use to control the forms or the forms of their gradient in semi-finished products and methods of heat treatment of products.

Keywords: shape memory effect, titanium nickelide, structure, heat treatment, aging.

Effect of surface condition on corrosion resistance of metallic medical materials

S.V. Skvortsova, A.A. Orlov, Yu.V. Chernyshova, A.V. Zairov, A.R. Chupikova

The article considers the influence of the surface condition on the corrosion resistance of alloys based on cobalt, titanium and stainless steel, which are currently used for the manufacture of components for implantable medical devices. showed that a change in the surface cleanliness (its roughness) has practically no effect on the corrosion resistance of alloys based on cobalt and titanium, which cannot be said about stainless steel. It is shown that the nitriding of titanium alloy samples by almost 500 mV shifts the stationary potential towards positive values, the nitriding of comochrome leads to a significant increase in the current density, and after nitriding stainless steel completely loses its corrosion resistance.

Keywords: titanium alloy, cobalt-chromium alloy, stainless steel, roughness, corrosion resistance.

Influence of induction hardening on the phase composition, structure, and hardness of VT6 titanium alloy

A.V. Neiman, O.A. Bytsenko, A.P. Neiman, E.O. Agarkova

The possibility of forming a finely dispersed structure by induction hardening with subsequent aging has been studied. It is shown that the resulting structure is represented by β-grains, as well as the secondary α^II-phase in the form of fine particles about 1 μm in size and α-rim of the initial β-grains. The formed structure provided a significant increase in hardness (up to 42 HRC units) compared to the initial state.

Keywords: induction hardening, hardness, titanium alloys, endoprostheses.

Polymorphic transformation of a pseudo-β titanium alloy of the Ti-Al-Mo-V-Cr-Fe system at high pressure

S.A. Osipov, S.Yu. Kuznetsov, A.A. Alexandrov, A.S. Oryshchenko, V.P. Leonov, I.M. Khachaturian, A.G. Padalko, A.V. Alexandrov

The paper presents the results of applying the technique for determining the temperature of the polymorphic transformation of a pseudo-β titanium alloy by the method of differential barothermal analysis.

Keywords: metal granules, powder, differential barothermal analysis, pseudo-β titanium alloy.

Processing technologies

The dependence of the decorative qualities of the anodic oxide film on titanium alloys on the mode and method of application

A.E. Avramenko, A.E. Dryukova

The article discusses the dependence of the quality of a decorative coating on titanium alloys, namely, colored monochromatic oxide films obtained by anodizing, on the current density at various voltage values and on application methods that are defined and described independently. For various voltage values, the possibility of deposition by the considered methods was revealed. For each method, graphs are compiled that determine the modes of deposition on the surface of the alloys.

Keywords: decorative anodizing, monophonic films, current density, application methods.

Improvement of production technologies of nitrogen- and carbon-containing vanadium master alloys for the titanium industry

A.A. Larionov, D.V. Taranov, M.V. Trubachev, S.A. Vohmentsev

Due to the development of new recipes for titanium alloys and the expansion of their applications, the requirements for the quality and range of master alloys intended for their smelting are constantly growing. In this work, using the example of complex vanadium master alloys with a high content of nitrogen and (or) carbon, only a part of the problems that manufacturers have to solve is highlighted. Over the past 15 years, scientific foundations have been developed, technologies for the production of a number of nitrogen and carbon-containing ligatures have been improved and introduced, which has contributed to improving the quality of smelted ingots and increasing the ingot-to-product yield.

Keywords: master alloy, vanadium, aluminum, nitrogen, carbon, titanium.