Optimizing high-temperature oxidation behaviors of high-Nb-containing TiAl alloys by addition of boron

Abstract The influence of boron addition on oxidation behaviors of high-Nb-containing TiAl alloys was investigated using isothermal oxidation tests at 900 °C in air. The results indicated that boron addition refined the lamellar colony structure and significantly improved the high-temperature oxidation resistance. Fine lamellar colonies were conducive to reducing thermal stress during oxidation, which delayed the cracking of the oxide scale. Furthermore, the generated oxide implants intensified the adhesive strength between the oxide scale and substrate, further enhancing the oxide-scale spallation resistance. In summary, the superior adhesion of the oxide scale resulted in a better oxidation resistance of the boron-containing alloy.