Microstructures and Wear Resistance of Si-Al-Y Co-Deposition Coatings on γ-TiAl Alloy

Abstract

Si-Al-Y co-deposition coatings on γ-TiAl alloy were prepared by pack cementation process at 1050°C for 3 h, Scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS), X-ray diffractometer(XRD) and microhardness tester were employed to investigate the surface morphologies, surface element distributions, microstructures, phase constitutions and microhardness of the coatings. Friction-wear tests of the γ-TiAl alloy substrate and the coatings were conducted in air at ambient temperature. The results show that the coating prepared by co-depositing Si-Al-Y had a multiple layer structure: the outer layer was composed of TiSi2, TiSi, Ti5Si4, Ti5Si3, the middle layer was composed of TiAl3, TiAl2, and the inner layer was Al rich layer. The microhardness of the surface is up to 1538HK0.49.The wear mass loss is only one half as much as that of γ-TiAl matrix, and the wear resistance increases significantly.