Surface hardening of VT6 titanium alloy in a gaseous environment in the dynamic vacuum mode

Keywords

VT6 titanium alloy,thermodynamic analysis of reactions, modification of surface layers, thermochemical treatment, oxidation, nitriding, phase composition.

Cite as

Student М. М., Luk’yanenko A. G., Student О. Z., Hvozdetskyi V. М., Veselivska H. H., and Proskurnyak R. V. Surface hardening of VT6 titanium alloy in a gaseous environment in the dynamic vacuum mode. Physicochemical Mechanics of Materials. 2026. 62(2), 070-077.

https://doi.org/10.15407/pcmm2026.02.070

Abstract

Based on the results of thermodynamic calculations, the most favorable conditions for the formation of diffusion-hardened layers on the surface of titanium alloys were substantiated. The surface layers of the specimens were modified by saturating them with oxygen or nitro­gen in a reaction chamber with precise control of their content (dynamic vacuum mode). In particular, after holding samples of VT6 titanium alloy for 5–7 h at a temperatu­re of 700–800°C in a reaction chamber with varying pressure of the oxygen-containing medium in it from 1.33´10^–3 to 0.133 Pa, layers with a thickness of 40–100 mm and a hardness of 3–7 GPa were obtained on their surface. Moreover, there was practically no external brittle phase film on such diffusion coatings. During diffusion saturation of tita­nium alloy specimens in nitrogen at a pressure of 0.133–10⁵ Pa for 5–10 h at a temperature of 750–850°C, a titanium nitride film 2–5 mm thick and with a hardness of 7–10 GPa was formed on their surface. Beneath this film, a diffusion layer 25–50 mm thick was formed, showing clear signs of gradient hardening.

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