Oxidation behaviour of Ag-containing TiAl-based intermetallics

摘要

The effect of alloy composition on the oxidation behaviour of gamma-TiAl alloys with silver additions was studied during exposure at 800 deg C in air. For this purpose, a number of Ti-Al-Ag alloys with systematic variation of the chemical composition was prepared by levitation induction melting. Subsequently, the alloys were isothermally and/or discontinuously oxidised at 800 deg C in air. The results showed that suitable silver additions can promote and stabilise formation of an alumina scale on gamma-TiAl up to the maximum test times of 12,000 h. An oxidation map was derived which allows defining which type of surface oxide is formed on various TiAl-Ag alloy compositions. This result can be applied in further work for development of oxidation resistant coatings for gamma-TiAl or/and Ti-based alloys.