Elastic and Anelastic Properties of Forged β-solidifying TiAl Alloys at High Temperatures

TiAl-based alloys are the most promising candidates to replace Ni-based superalloys in advanced aerospace and automotive engines due to their high specific yield strength and good oxidation resistance. In this study, we examined the elastic and anelastic properties of forged Ti–43Al–5V–4Nb (in at.%) alloys with nearly lamellar and triplex microstructures at temperatures between 40 and 760 ℃ using resonant ultrasound spectroscopy. The Young’s modulus of the TiAl alloy with the triplex microstructure was comparable to that of the alloy with the nearly lamellar microstructure. In addition, the triplex-microstructure TiAl alloy exhibited a significant energy loss for shear vibration modes. The ω-phase, which forms in the β-phase due to thermomechanical processing and subsequent heat treatments, is most likely responsible for these results. Internal friction measurements revealed an acoustic loss peak at approximately 200 ℃, which could also be related to the ω-phase. These results suggest that the ω-phase significantly affects the elastic and anelastic properties of forged β-solidifying TiAl alloys.