Enhanced high-temperature mechanical behavior of an in situ TiAl matrix composite reinforced with alumina

A Ti-45Al-3Cr-2.5Nb alloy reinforced with in situ formed alumina has been produced by means of centrifugal casting by adding zirconium oxide in the crucible. The dispersion-strengthened alloy has been characterized to verify its microstructure and particle distribution. Mechanical tests carried out over the temperature range 850-950 degrees C highlighted that in situ formed alumina allows to increase the alloy yield stress by 21% at 850 degrees C and by 35% at 900 degrees C. Moreover, the in situ formed oxide particles produced an increase of the Young's modulus of about 10% at 850 degrees C and of about 8% at 900 degrees C. Considering that the tested alloy has a density that is about a half of nickel superalloys, obtaining high specific mechanical properties over the temperature range 850-950 degrees C can boost its application in the production of turbine blades.