为了研究固溶温度对GH4099合金环锻件显微组织和力学性能的影响，设计了环轧后锻件固溶处理温度为1 080、1 100和1 120 ℃，保温时间均为1 h，时效处理制度为900 ℃条件下保温5 h的热处理试验，并开展相关的组织分析和力学性能测试。采用扫描电子显微镜（SEM）、电子探针显微分析（EPMA）、JMatpro软件计算和力学实验检测等手段研究了不同固溶温度下GH4099合金环锻件的显微组织和力学性能。结果表明，1 080、1 100和1 120 ℃固溶处理后γ′相的平均尺寸分别为47.3、48.5和49.3 nm，体积分数分别为30.1%、31.0%和29.9%，由此可见，固溶温度对γ′相的尺寸、含量及分布影响不大。随着固溶温度的升高，合金硬度呈下降趋势。晶内颗粒状M₂₃C₆随着固溶温度的上升逐渐发生回溶，当温度达到1 120 ℃时，晶内M₂₃C₆几乎完全回溶。固溶温度在1 100 ℃以下时，晶粒细小，组织均匀；固溶温度在1 100 ℃以上时，晶粒尺寸出现明显的长大现象，并且经时效处理后，M₂₃C₆型碳化物呈链状析出于晶界，使晶界由平直状变为弯曲状，弯曲晶界显著提升了合金的持久寿命。持久试样断口附近晶粒组织被拉长，晶界处存在大量的孔洞，该现象表明沿晶断裂为该合金裂纹萌生和扩展的主要机制。此外，1 120 ℃固溶处理时，合金内部组织不均匀，出现混晶现象；由此可知，GH4099合金环锻件的最佳固溶处理温度为1 100 ℃。

In order to study the effect of solution temperature on the microstructure and properties of GH4099 alloy ring forgings, a heat treatment test was designed with solution treatment temperature of 1 080, 1 100 and 1 120 ℃, holding time of 1 h and aging treatment system was 900 ℃ and the holding time was 5 h. Then, the microstructure analysis and mechanical properties test were carried out. The effect of solution temperature on the microstructure and properties of GH4099 alloy ring forgings was investigated by SEM, EPMA, JMatPro software and mechanical experiment detection. The results show that, after the solid solution treatment at 1 080, 1 100 and 1 120 ℃, the average size of the γ′phase is 47.3, 48.5 and 49.3 nm, respectively, and the volume fraction is 30.1%, 31.0% and 29.9%, respectively. It can be seen that the solid solution temperature has little effect on the size, content and distribution of γ′phase. With the increase of solution temperature, the hardness of the alloy decreases. The granular M₂₃C₆ carbide in the crystal gradually dissolved with the rise of solid solution temperature. When the temperature reached 1 120 ℃, the M₂₃C₆ in the crystal almost completely dissolved. The fine and uniform grain can be obtained below 1 100 ℃; when the temperature is above 1 100 ℃, the grain size grows obviously, and the M₂₃C₆ carbide precipitate in a chain shape at the grain boundary after aging, which makes the grain boundary change from flat to curved. The curved grain boundary can effectively improve the rupture life of the alloy. The grain structure near the fracture of the durable specimens is elongated, and there are a lot of voids at the grain boundaries, which indicates that intragranular fracture is the main mechanism of crack initiation and propagation in the alloy. In addition, uneven internal texture and mixed crystal phenomenon occur in the alloy when solution treatment temperature is 1 120 ℃. Therefore, the best solution treatment temperature for GH4099 alloy ring forgings is 1 100 ℃.