Advances in phase relationship for high Nb-containing TiAl alloys

Yong-Feng Liang¹，Xiang-Jun Xu²，Jun-Pin Lin¹

1. State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing2. Materials and Chemistry School,Zhongyuan University of Technology

摘 要：γ-TiAl alloys,including two categories（the conventional TiAl and the high Nb-containing TiAl（high Nb-TiAl））,are technologically intriguing because of their applications at high temperatures.Specifically,the service temperature of the high Nb-TiAl alloys is 60-100℃higher than that of conventional TiAl alloys.Recently developed TiAl alloys,for example TNB,TNM,β-γ alloys,belong to the high Nb-TiAl alloys,displaying similar behavior in phase transformation,strengthening,oxidation at high temperatures,and relationships between composition,microstructure,and mechanical properties.This work presents an in-depth review of the high Nb-TiAl alloys regarding the advances in phase diagram,formation mechanism of the new γ₁ phase,microsegregation induced by adding a high content of alloying element Nb,and the mechanism of the B2/ω phase formation.Some challenges in developing the high Nb-TiAl alloys are also discussed.

关键词：