GH4800镍基高温合金具有良好的高温强度和组织稳定性，但其铸态组织不均匀及热变形过程中动态再结晶规律尚不明确，制约了热加工参数的合理制定。为了阐明铸态GH4800合金在不同热变形条件下的流变行为、组织演变及动态再结晶机制，并确定适宜的热加工窗口，本工作系统探究了一种新型镍基高温合金GH4800在不同热变形条件下的微观结构特征及其行为，重点揭示动态再结晶机制。借助OM、SEM和EBSD技术对样品进行表征，并构建了热加工图和动态再结晶临界应变模型、体积百分比模型。结合所构建的模型，获得了最佳热加工参数，并分析了显微组织演变过程，包括晶粒尺寸变化、晶界特征等指标。结果表明，该合金的再结晶机制主要受变形量、变形温度、应变速率等因素的共同影响。

Study systematically investigates the microstructural characteristics and evolution behavior of the nickel-based high-temperature alloy named GH4800 alloy under different hot deformation conditions, with a focus on elucidating dynamic recrystallization behavior and grain refinement mechanisms. Using optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) techniques, the microstructural samples were thoroughly characterized. To gain a deeper understanding of the dynamic recrystallization process, a thermal processing map and a mathematical model of dynamic recrystallization volume fraction for the alloy were established to reveal the recrystallization behavior of the GH4800 alloy under various deformation conditions. By combining the constructed model, optimal hot processing parameters were obtained, and the evolution of the microstructure was analyzed, including changes in grain size, grain boundary characteristics, and recrystallization fraction. The study found that the recrystallization mechanisms of the GH4800 alloy are mainly influenced by the combined effects of deformation amount, deformation temperature, and strain rate. This work provides a theoretical foundation for optimizing the hot processing parameters of GH4800 alloy and offers guidance for the design of alloy heat treatment processes.