ResearchProgress on the Ductilization Mechanisms of TiAl Alloys
Author of the article:ZHEN Zhonghao1,2,3, CHANG Chen1,2,3, WEI Daixiu1,2,3, WANG Xianghui1,2,3, ZHU Demin1,2,3, LIU Xu1,2,
Author's Workplace:1. State Key Laboratory of Light Superalloys, Nanjing Research Base, Nanjing University of Science andTechnology, Nanjing 210094, China; 2. National Key Laboratory of Advanced Casting Technologies, Nanjing University of Science and Technology, Nanjing 210094, China; 3. Nanjing Belight Laboratory, Nanjing 210094, China
Key Words:TiAl alloys; room-temperature plasticity; alloying; microstructure; manufacturing technology
Abstract:
Aspivotal lightweight high-temperature structural materials in the aerospace field, TiAl alloys face major bottlenecks that restrict their engineering applications because of the poor workability resulting from their intrinsic room-temperature brittleness. A systematic review of recent research progress regarding the ductilization mechanisms of
TiAl alloys is provided in this paper. It elucidates the underlying mechanisms by which alloying elements (such as V, Cr, and Mn) and trace elements (such as B, C, and Y) influence ductility. The influence of microstructural evolution on mechanical properties is analysed in depth, with a particular focus on the critical roles of long-period stacking ordered (LPSO) structures and polysynthetic twinned (PST) single crystals in achieving synergistic strength and ductility enhancement. With respect to fabrication processes, the breakthroughs achieved by techniques such as investment casting, canned forging/rolling, and selective electron beam melting (SEBM) in mitigating forming defects and optimizing solidification microstructures are comparatively analysed. Finally, integrated precision control based on the multiscale correlation of "composition-microstructure-process" is proposed as the core direction for the future development of TiAl alloys.