Cyclic Oxidation of Aluminide Coated Two Phase α2-Ti3Al/γ-TiAl Alloys at 1000oC

Titanium aluminide alloys have been considered as the candidates to substitute nickle-base superalloys for high temperature applications in aircraft turbine engines, as the alloys has lower density. For such applications, the alloys should exhibits both strength and high temperature oxidation or corrosion. Therefore, external protective scale of Al2O3 has to be easily developed in the alloys, and the scale should resist for cyclic thermal operations. Recently, pack aluminide coatings have been developed on two phase α2-Ti3Al/γ-TiAl alloys of Ti-47Al-2Nb-2Cr-0.5Y-0.5Zr, to provide TiAl3 based coatings capable in providing external scale of Al2O3. Nevertheless, no cyclic oxidation test has been conducted in this system. This paper reports the cyclic oxidation behavior of un-coated and pack aluminide coated α2-Ti3Al/γ-TiAl alloys at 1000oC.