Investigation of formation of hardened layer on titanium alloys by the method of ion-plasma nitriding
| Autor: | A. N. Drobov, I. G. Oleshuk, I. L. Pobol, Sun Feng, Wang Lin |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Metallurgy chemistry.chemical_element Titanium alloy 02 engineering and technology General Medicine Tribology Microstructure 01 natural sciences Indentation hardness Fatigue limit 010305 fluids & plasmas Corrosion 020303 mechanical engineering & transports 0203 mechanical engineering chemistry 0103 physical sciences Nitriding Titanium |
| Zdroj: | Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series. 64:25-34 |
| ISSN: | 2524-244X 1561-8358 |
| Popis: | Various methods are applied in the world practice to increase wear resistance, fatigue strength and corrosion resistance of aviation equipment, machinery and medicine parts made of titanium and its alloys. Ion-plasma nitriding provides the ultimate effect making it possible to obtain hardened layers with hardness of HV0.01 650–1000 with a thickness of 0.07–0.20 mm for 3–6 hours, depending on the grade of the titanium alloy.Technological factors effecting on the efficiency of ion-plasma nitriding of materials are the process temperature, duration of saturation, pressure, composition and flow rate of the working gas mixture. The effect of these technological parameters on the microstructure, microhardness and depth of hardened layers is investigated in the work. It is shown that hardness and depth of the nitrided layer can be controlled by changing the composition, volume and periodicity of the gaseous medium (nitrogen and argon) supply at the stages of heating and holding time of the samples from titanium and its alloys under ion-plasma nitriding. The tribological characteristics of titanium alloys as-received and the same ones subjected to ion-plasma nitriding under friction conditions without a lubricant were studied. For VT1-0 and VT6 alloys in the as-received state during the tests there is a monotonous decrease of the friction coefficient from 0.35–0.40 to 0.25, after nitriding the friction coefficient monotonically increases from 0.14 up to 0.30 when removing the hardened layer.Studies of corrosion resistance of titanium VT1-0, carried out in a 10 % solution of sulfuric acid, showed that after ion-plasma nitriding at a temperature of 830 °C for 6 hours, the corrosion resistance increases, as the positive polarization potential of the sample shows. |
| Databáze: | OpenAIRE |
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