TiAl 合金具有低密度、高比刚、高比强、优异的高温力学性能等优点，在航空航天领域极具广阔的应用前景。 然而，由于该合金低的室温塑性、损伤容限及加工性能，导致其制造成本较高，限制了应用领域。 均匀细小的显微组织可以显著改善 TiAl 合金的室温塑性及加工性能。 本文综述了高温淬火获得亚稳组织转变并细化 TiAl 合金组织的相关研究，如块状 γM 相、马氏体 α′相及全 B2 相转变等。 在回火过程中，亚稳组织的分解可以细化合金组织，亚稳组织过冷度越大，析出相形核率越高，晶粒细化效果更为显著。 讨论了各种组织细化方法存在的问题和对力学性能的影响。

TiAl alloy has the advantages of low density, high specific stiffness, high specific strength, excellent high temperature mechanical properties, and has a broad application prospect in the aerospace field. However, due to the low room temperature plasticity, damage tolerance and machining properties of the alloy, the high manufacturing cost of the alloy limits its application field. The uniform and fine microstructure can significantly improve the room temperature ductility and machining properties of TiAl alloy. The metastable microstructure transformation, such as massive γM phase, martensite α′ phase and full B2 phase transformation, obtained by high temperature quenching and refined TiAl alloy microstructure were reviewed. In the tempering process, the decomposition of metastable microstructure can refine the alloy microstructure. The higher the subcooling degree of metastable microstructure, the higher the nucleation rate of precipitated phase, and the grain refinement effect is more significant. The problems existing in various methods of microstructure thinning and their effects on mechanical properties were discussed.