A review of microstructure control and mechanical performance optimization of γ-TiAl alloys

Upgrading and developing metallic materials are bases for improving the performance of aircraft. As one of the new structural metallic materials used in aerospace, lightweight and high-strength γ-TiAl alloys have been successfully used as high-risk structural parts in aircraft engines. Nonetheless, intrinsic embrittlement is the main factor limiting applications of γ-TiAl alloys. To further enlarge the application fields of γ-TiAl alloys, it is urgent to improve mechanical properties, like strength and ductility. This paper first introduces phase constituents and precipitates of γ-TiAl alloys, summarizes microstructure control measures of γ-TiAl alloys, and presents texture evolutions of γ-TiAl alloys. Then, based on four strength mechanisms, this review paper summarizes factors influencing mechanical properties of γ-TiAl alloys during compression, tension, creep and fatigue as well as tribology tests. It also includes the fracture mechanisms of γ-TiAl alloys. Finally, this paper proposes some future development directions for studying γ-TiAl alloys, like screening chemical compositions via machine learning technology, and developing microstructure evaluation software.