A new high-temperature, oxidation-resistant Ti-based material

Ti3Al(O)-Al2O3 composites were fabricated in situ using a mechanical-alloying and reaction-sintering technique. Their oxidation behaviors were studied in air at 700-900degreesC. The oxidation rates were much lower than those of Ti3Al. The behaviors of isothermal and cyclic oxidation were very similar. The oxide scales that formed exhibited excellent spallation resistance under all testing conditions. No scale cracking or spallation could be observed, even along the edges or corners of the samples, implying that growth and thermal stresses generated during heating and cooling periods had been effectively released. The mechanisms of the decrease in oxidation rate and the improvement on spallation resistance are discussed based on microstructure studies. This composite has advantages of light-weight, simple fabrication from inexpensive materials, and superior high-temperature oxidation resistance; it may provide opportunities to be used in some high-temperature structural applications.