Titanium aluminides are particularly interesting for high temperature applications because they offer good high temperature strength combined with low density.
A major limitation of their use has been their poor oxidation resistance, since they form mixed oxide scales (TiO2/Al2O3).
Solution: Halogen effect (F, Cl, Br, I) → Formation of a protective Al2O3 layer
Top: Metallographic cross-sections
Bottom: TiAl turbocharger rotors after high temperature exposure
An innovative contribution to the economy: