Cyclic oxidation behavior of TiAl composites incorporated with TiB2 dispersoids

TiAl alloys incorporated in (0,3,5,10) wt.% TiB2 dispersoids were manufactured via mechanical alloying-spark plasma sintering (MA-SPS), and their cyclic oxidation characteristics were studied at 800, 900 and 1000 degreesC in air. The cyclic oxidation resistance of the prepared TiAl-TiB2 composites effectively increased with increases in TiB2 content. The oxide scale formed consisted of an outer TiO2 layer, an intermediate Al2O3 layer, and an inner (Al2O3+TiO2) mixed layer. The scale adherence was relatively good, and much thinner oxide scales, when compared to TiB2-free TiAl alloys, were formed on the prepared composites. The incorporated TiB2 dispersoids oxidized to TiO2 and B2O3 which evaporated during oxidation.