Analysis of interface reactions of TiAl/Al2O3 and TiAl/TiO2 by the use of chemical potential diagram

Interface reactions for the diffusion couples of TiAl/Al2O3 and TiAl/TiO2 were investigated and the reaction paths were analyzed by the use of chemical potential diagram. No essential reaction was observed at 1273 K for the diffusion couple of TiAl/Al2O3, but Ti3Al(O) was formed between TiAl(O) and Al2O3 phases at 1373 K. In the case of TiAl/TiO2, Ti3Al(O) and Al2O3 were formed between TiAl(O) and TiO2 phases. These reaction paths were reasonably elucidated by the use of chemical potential diagram of the Ti-Al-O system, which was constructed using the data of Gibbs energy of formation for the compounds composed of Ti, Al and O. The reaction paths for the diffusion couple of Ti/Al2O3 and oxidation of TiAl obtained from the literature data were also reasonably elucidated by the use of the same chemical potential diagram.