TiAl合金是一种新型轻质耐高温金属结构材料，其优势在于低密度、高比强以及优异的高温性能。然而，由 于TiAl 合金具有热加工窗口窄、高温变形能力不佳等问题，这导致合金构件成形困难。 添加β稳定元素可以引入高温 下无序的β相，显著增强合金的热变形能力，但元素对合金热变形行为的具体影响机制尚不明晰。 基于此，以Ti-43Al 0.5Re-xCr（x=1、1.5、2，原子分数，%）合金为研究对象，分别在 1150、1200、1250℃温度下热压缩。 分析不同条件下的流 变曲线，并研究温度及Cr含量对合金热变形组织及动态再结晶行为的影响，同时阐明了Ti-43Al-0.5Re-1.5Cr合金 在1200℃/0.01 s-1 热变形条件下的微观组织演变。 结果表明，合金整体流变应力随温度和Cr含量的升高而降低。 合金 在1150℃热变形，组织中存在大量残余片层团，主要发生片层团的弯曲扭折破碎，因此变形抗力较高；而在1200 和1250℃热变形，合金组织大部分为高温无序α相，主要发生α相的连续动态再结晶，因此变形抗力低。随着Cr含量 提高，高温下为BCC结构的β相含量提高，因此变形抗力降低。在1200℃/0.01s-1/40%变形条件下，合金再结晶程度随 β 相含量提高而增加， 因此Cr含量的增加会提高合金中β相的含量进而促进合金的动态再结晶过程。 在Ti-43Al 0.5Re-1.5Cr 合金 1 200 ℃/0.01 s-1/40%条件下的变形组织中发现细小 β 相周围分布有大量小角晶界，其相连形成大量小 尺寸亚晶，因此形成更加细小的再结晶晶粒，β相起到了细化再结晶晶粒的作用。 通过研究Ti-43Al-0.5Re-1.5Cr合金不 同应变量条件下的微观组织，最终得出合金在1200℃/0.01s-1热变形条件下的微观组织演变规律。

TiAl alloys, novel lightweight, high-temperature metal structural materials, feature low density, high specific strength, and excellent high-temperature performance. However, its narrow hot working window and poor deformation at high temperatures make the formation of alloy components difficult. Adding β-stabilizing elements enhances hot deformation by introducing a disordered β-phase, but the mechanism is unclear. Therefore, Ti-43Al-0.5Re-xCr (x=1, 1.5, 2, at.%) alloys were used as the research objects, and thermal mechanical compression experiments were conducted at 1 150, 1 200 and 1 250 ℃. Flow curves under different conditions were analysed, the effects of temperature and Cr content on the thermal deformation microstructure and dynamic recrystallization were studied, and the microstructural evolution of the Ti-43Al-0.5Re-1.5Cr alloy at 1 200 ℃/0.01 s-1 was clarified. The results indicate that the overall flow stress of the alloy decreases with increasing deformation temperature and Cr content. When the alloys are deformed at 1 150 ℃, many residual lamellar colonies exist in the microstructure that primarily fragment through bending, twisting, and breaking, leading to high deformation resistance. When the alloys are deformed at 1 200 or 1 250 ℃, most of the alloy microstructure is the α phase, which undergoes continuous dynamic recrystallization, resulting in low deformation resistance. Under deformation conditions of 1 200 ℃, a 0.01 s-1 strain rate, and 40% deformation, the degree of recrystallization in the alloy increases with increasing β phase content. Thus, an increase in the Cr content enhances the content of the β phase in the alloy, which promotes the dynamic recrystallization process of the alloy. In the deformed microstructure of the Ti-43Al 0.5Re-1.5Cr alloy at 1 200 ℃, a strain rate of 0.01 s-1, and 40% deformation, many low angle grain boundaries (LAGBs, 2° ~15° misorientation) are distributed around the fine β phases, which interconnect to form numerous small-sized subgrains, resulting in the formation of fine recrystallized grains. Thus, the β phase plays a role in refining the recrystallized grains. The microstructures of the Ti-43Al-0.5Re-1.5Cr alloy samples subjected to different strains were studied, revealing their microstructure evolution at 1 200 ℃/0.01 s-1 hot deformation.