Cyclic Oxidation Behaviour of Halogen Implanted Ti-46.5Al-4(Cr, Nb, Ta, B)

摘要

Intermetallic alloys based on titanium aluminides, especially γ-TiAl (Ti-50at.%Al), are of great attraction for structural high temperature applications e.g. in aero engines because of their low specific weight (about 4g/cm~3) and their good mechanical properties at elevated temperatures. However, the use of TiAl alloys is still limited to a temperature of approximately 750℃ due to their poor oxidation resistance at higher temperatures. The oxidation behaviour of TiAl alloys has to be improved before these alloys can be used at temperatures of 800℃ and above. The improvement of the oxidation resistance of γ-TiAl can be achieved by small amounts of halogens F, Cl, Br and I (so called halogen effect). The halogens can be incorporated in several ways e.g. by ion implantation. In this paper results of a technical TiAl alloy called γ-MET [Ti-46.5Al-4(Cr, Nb, Ta, B)] with and without implantation are presented.