Microstructure and properties of titanium aluminides on Ti6A14V titanium alloy produced by chemical vapor deposition method

摘要

Microstructure, phase composition, and properties of the titanium aluminide diffusion layers produced on Ti6A14V by Chemical Vapour Deposition (CVD) at various process parameters were investigated. It was found that the layers produced by CVD contain a mixture of the Ti_2AlN + TiAl_2+Ti_3Al phases, while the additional heat treatment step after CVD changes the composition of the layers into the TiN + Ti_2AlN + TiAl + Ti_3Al mixture. The layers are characterized by high hardness of about 800 HV0.05 after CVD aluminizing and about 850 HV0.05 after CVD aluminizing followed by heat treatment, and by good adhesion to the substrate. Their corrosion resistance is only slightly lower than that of the Ti6A14V alloy substrate and is fully adequate to a wide range of applications.