OUT-OF-VACUUM ELECTRON-BEAM SURFACING OF AN INTERMETALLIC Ti-Al-Cr-Nb-Si COATING ON A TITANIUM ALLOY: STRUCTURE AND PROPERTIES
D.V. Lazurenko1,2,3, G.D. Dovzhenko1,2, A.A. Ruktuev1, R.I. Kuz'min1, N.S. Aleksandrova1,2, E.V. Domarov4, V.S. Shikalov1,5, K.E. Kuper2,3,4
1Novosibirsk State Technical University, Novosibirsk, Russia
2Siberian Circular Photon Source (Synchotron Radiation Facility), Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
3Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
4Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
5Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch of the Russian Academy of Sciences, ovosibirsk, Russia
Keywords: out-of-vacuum electron-beam surfacing, energy-dispersive diffraction, X-ray synchrotron radiation, titanium aluminides, wear resistance, heat resistance
Abstract
A 2.3-mm-thick coating based on titanium aluminides with Cr, Nb, and Si additions is formed on the surface of a VT20 titanium alloy by out-of-vacuum electron-beam surfacing. Energy-dispersive X-ray diffraction combined with energy-dispersive X-ray spectroscopy is used to assess the homogeneity of the coating thickness. The concentrations of aluminum and alloying elements in the deposited layer are found to vary slightly across its thickness, which affects the ratios of the main phases (γ-TiAl, α₂-Ti3Al, Ti5Si3) formed in the coating, while the composition remains qualitatively unchanged. Such variations are not expected to have a significant effect on the coating properties across its thickness. The wear resistance of the deposited layer under dry sliding friction is found to be 2.5-fold higher than that of the base metal, and its mass gain at 1100 °C is 6.5-fold lower than that of the VT20 titanium alloy.
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