TiAl 金属间化合物定向技术研究进展

TiAl alloys with low density and good high-temperature properties, are regarded as a new type of structural material with great application potential in the aerospace field. The fully lamellar TiAl alloy with columnar/single crystal structure exhibits excellent comprehensive mechanical properties at high temperatures. This paper first introduces the basic concepts of directional TiAl alloys, such as development background, directional structure, and mechanical property anisotropy. Then, based on the three aspects including working principle, key technology, and structural characteristics, the directional technologies such as traditional Bridgman method, optical floating zone method, electromagnetic constraint, and electromagnetic cold crucible are discussed. Furthermore, combined with the latest research results, the work of preparing TiAl alloys by directional annealing is elaborated. Finally, the research direction of directional technology in TiAl alloys is prospected, and it is pointed out that new principles and technologies need to be developed in terms of optimizing composition design, controlling microstructure/phase transformation, and stably producing large-scale directional crystals.