Abstract: Different parameters such as deformation temperature and deformation rate were set for thermal compression tests， using the Thermecmastor-Z thermal simulation testing machine. The stress-strain curves and metallographic structures were analyzed to systematically study the high-temperature thermal deformation behavior and morphological evolution of the GH500 superalloy. The results showed that the stress-strain curves exhibited characteristics of work hardening， dynamic recovery， and dynamic recrystallization， with stress significantly increasing as the deformation temperature decreased and the deformation rate increased. At a deformation rate of 1 s^-1， as the deformation temperature increased， the microstructure of the alloy evolved from deformed grains and small clusters of grains into fully recrystallized grains. When the deformation temperature was ≥1 130 ℃， the volume fraction and size of the dynamic recrystallized grains of the alloy significantly increased with the rise in deformation rate. At a deformation temperature of 1 180 ℃ and a deformation rate of 1 s^-1， the alloy underwent complete dynamic recrystallization with no deformed grains， resulting in fine and uniform grains. Based on the stress-strain curves and microstructural evolution obtained from hot compression tests， suitable forging processes have been explored. The heating temperature was set between 1 130 ℃ and 1 150 ℃， and the reduction speed was 10 mm/s to 15 mm/s with the deformation rate betweem 0.04s^-1  and 0.06 s^-1 during the forging process. The produced disc alloy exhibit a basically uniform grain structure. After standard heat treatment， the room temperature tensile strength， hardness， and high-temperature durability of disc alloy meet the standard requirements.

Key words: Deformation Temperature, Deformation Rate, Dynamic Recrystallization, Microstructure

摘要： 采用Thermecmastor-Z热模拟试验机，设置不同变形温度、应变速率等参数进行热压缩试验，结合应力应变曲线和金相组织进行分析，系统研究GH500高温合金高温热变形行为及组织形貌演变规律。结果表明：应力应变曲线呈现出加工硬化、动态回复和动态再结晶特点，应力随变形温度的降低和应变速率的升高显著增加。应变速率为1 s^-1，随着变形温度的提升，合金的微观组织由变形晶粒加细小团簇的晶粒演变成完全再结晶晶粒。当变形温度≥1 130 ℃，随着应变速率的提升，合金的动态再结晶晶粒体积分数及尺寸明显增加。变形温度1 180 ℃、应变速率1 s^-1，合金动态再结晶充分、无变形晶粒，晶粒细小均匀。根据热压缩试验得到的应力应变曲线和组织演变规律，摸索出合适的模锻工艺，加热温度1 130~1 150 ℃、压下速度10~15 mm/s，锻造过程应变速率为0.04~0.06 s^-1，生产出的圆饼合金晶粒基本均匀，圆饼合金经标准热处理后室温拉伸、硬度及高温持久性能满足标准要求。

关键词: 变形温度, 应变速率, 动态再结晶, 微观组织