THE INFLUENCE OF NIOBIUM ION-IMPLANTATION ON THE HIGH-TEMPERATURE OXIDATION BEHAVIOR OF TI-48AL-2CR

The effect of niobium addition by ion implantation on the corrosion be haviour of a gamma-TiAl-based intermetallic alloy Ti-48Al-2Cr in air a t 800 degrees C was studied. Comparison was made with a material in wh ich niobium was added by alloying. Some experiments were carried out i n which niobium was implanted into the oxide scale of pre-oxidized Ti- 48Al-2Cr. The addition of niobium to the alloy appeared to improve the oxidation resistance significantly in both isothermal and cyclic oxid ation tests. Possible mechanisms for the effect of niobium on the oxid ation resistance of TiAl-based intermetallics are discussed in view of the results obtained for the implanted material.