Ion implantation technique as research tool for improving oxidation behaviour of tial based intermetallic alloys

Abstract

The effect of various elements added by ion implantation on the isothermal (up to 150 h) and cyclic (up to 1500 h) oxidation behaviour of γ-TiAl based intermetal lic alloys at 800 and 900°C in air has been studied. At 800°C ion implantation of Si, Nb, Ta, W, and Al showed a large beneficial effect on the oxidation behaviour of Ti–48Al–2Cr. A minor effect was found for Ti, Mo, Y, Mn, Pt, Rh, and Cr. More important was the oxidation of specimens implanted with Si or Nb, which revealed similar results to those for the intermetallic materials alloyed with these elements, i.e. Ti–47Al–2Cr–0·2Si and Ti–48Al–2Cr–2Nb. From this point of view it was concluded that the ion implantation technique can be employed as a ‘screening’ test for evaluating the effect of possible alloying additions. As a followup this technique was used as a research tool to study the effect of Nb, Pt, Rh, Si, Ta, and W on the oxidation behaviour of two types of Nb bearing TiAl based intermetallic alloys, i.e. Ti–48Al–2Cr–2Nb and Ti–48Al–2Mn–2Nb, at 900°C in air. In this case, no significant effect of the implanted elements on the isothermal and cyclic oxidation behaviour was found.