Cyclic-Oxidation Behavior of Ti3Al0.7Si0.3C2 Compounds Between 900 and 1100 A degrees C in Air

Abstract

Dense, monolithic Ti3Al0.7Si0.3C2 compounds were cyclically oxidized between 900 and 1100 A degrees C in air for 100 h. Ti3Al0.7Si0.3C2 oxidized into rutile-TiO2, alpha-Al2O3, and amorphous SiO2, accompanied by the evaporation of carbon. Ti3Al0.7Si0.3C2 had good thermal shock resistance, so that adherent oxide scales formed, regardless of their thickness. The cyclic oxidation resistance of Ti3Al0.7Si0.3C2 was poorer than that of Ti3SiC2, Ti3AlC2, and Cr2AlC. The thermal cycling did not affect the scale morphology or the oxidation mechanism that was identified in the isothermal oxidation tests, due mainly to the formation of the adherent oxide scales.