Evaluation of Lifetime of FGMs Disilicide Coatings for γ-TiAl Intermetallic Compound
The NbSi2/Nb/-TiAl and NbSi2/Nb functionally graded materials (FGMs) were prepared and their tolerances tested by exposing them to temperatures from 1050 °C to 1250 °C under vacuum and in air. Oxygen resistivity was estimated from metallographic investigations. The FGM lifetime was estimated by using a diffusion equation that considers the disappearance of the NbSi2 and Nb interlayer. These occurred during NbSi2 oxidation and Si diffusion from NbSi2 to Nb and interdiffusion between Nb and -TiAl. The results were validated by diffusion equations.
Akira Kawasaki, Akinaga Kumakawa and Masayuki Niino
M. Ohshima et al., "Evaluation of Lifetime of FGMs Disilicide Coatings for γ-TiAl Intermetallic Compound", Materials Science Forum, Vols. 631-632, pp. 495-500, 2010