Research progress on high-temperature coupling damage in TiAl alloys

• The influence rules of coupled damage on TiAl alloys at high-temperature conditions are systematically summarized for the first time. • The core development directions for regulating coupled damage in TiAl alloys are put forward for the first time. • The challenges and new solutions in TiAl alloys are prospected for the first time. • The multi-type damage mechanisms of TiAl alloys are systematically sorted out. The titanium aluminide (TiAl) alloys hold significant application potential in aerospace and related fields due to their low density, high specific strength, good thermal resistance, as well as excellent high-temperature creep resistance and oxidation resistance. In practical high-temperature service environments, the TiAl alloys frequently experience synergistic interactions among various damage mechanisms, including creep, fatigue, and oxidation, which can severely impair their mechanical integrity and reduce component lifetime. This review presents a critical overview of the predominant high-temperature damage modes in TiAl alloys, focusing on the mechanisms and research advancements related to creep damage, fatigue damage, and oxidation damage. This paper further explores coupled damage mechanisms such as thermomechanical fatigue, creep-fatigue interaction, creep-oxidation interaction and environmental hydrogen embrittlement. Additionally, it discusses strategies for enhancing damage resistance through the design of alloying elements and the application of coating technologies in detail. Currently, understanding of the coupled damage mechanisms in high-temperature TiAl alloys remains incomplete, and further research is hindered by the complexity of multi-field coupling and the limitations of the intrinsic properties of material. Future efforts should concentrate on achieving a more profound understanding of the microscopic mechanisms underlying coupled damage, as well as on the development of more effective alloying and coating technologies. These advancements are essential to meet the increasing performance demands for high-temperature TiAl alloys in aerospace applications.