在多道次热包套轧制变形后，冷却速率对TiAl合金板材的显微组织演变及其宏观力学性能具有显著的调 控作用。 以Ti-43Al-4Nb-1Mo-0.2B(原子分数，%，简称 TNM 合金)合金为研究对象，通过炉冷及空冷两种冷却方式调控 轧后冷却速率，系统研究了不同冷速下TNM合金板材显微组织形貌、相变过程及再结晶行为，进而对合金室温力学性 能进行测试并阐明其变形机制。 研究结果表明，缓冷促进了α2 /γ片层团内部及边界处α2 →βo相变，同时有利于片层团 周围等轴γ再结晶形核以及长大。 而快冷促进了α2 →γ相变，α2 /γ片层间距由缓冷条件下的140nm减小至60nm。 此 外， 快冷条件下形成非均匀厚度的γ板条以及片层团周围少量的γ再结晶使得TNM合金板材的室温强塑性同时提 高，抗拉强度达到1140MPa，断裂应变超过1%。

 Cooling rate significantly influences the microstructural evolution and mechanical properties of TiAl sheets following multipass hot-pack rolling. In this study, Ti-43Al-4Nb-1Mo- 0.2 B (at.% , TNM) sheets were prepared through furnace-cooling and air-cooling methods after rolling. The microstructural morphology, phase transformation, and recrystallization behavior of TNM sheets were systematically investigated at different cooling rates. Furthermore, the mechanical properties of the alloy at room temperature were evaluated, and the underlying deformation mechanisms were clarified. The results indicate that slow cooling facilitates the α2 →βo phase transition both within and at the boundaries of α2 /γ lamellar colonies while also promoting the nucleation and growth of equiaxed γ recrystallized grains surrounding these colonies. However, compared with slow cooling, rapid cooling promotes the α2 →γ phase transition, resulting in a decrease in the α2 /γ interlamellar spacing from 140 nm to 60 nm. In addition, the strength and plasticity of the TNM sheets are simultaneously enhanced because the γ laths have heterogeneous thicknesses and few γ recrystallized grains surround the α2 /γ lamellar colonies under rapid cooling conditions, achieving a tensile strength of 1 140 MPa and an engineering strain exceeding 1%.