为系统揭示FGH96合金静态再结晶机制，指导其固溶处理工艺制定，本工作在1100~1260 ℃温度范围内对锻态FGH96合金进行固溶处理，采用EBSD及TEM等手段研究了FGH96合金静态再结晶过程中的显微组织演化规律，分析了FGH96合金静态再结晶机制及Σ3孪晶界的形成机理。结果表明，固溶温度会影响FGH96合金的晶粒尺寸及晶界特征(小角度晶界、大角度晶界和Σ3孪晶界)，且随着固溶温度提高，晶粒尺寸及晶界特征呈现出特定的演化规律。FGH96合金的静态再结晶机制以亚晶形核长大机制为主，且在静态再结晶过程中，平行于(\mathrm{11}\overline{\mathrm{1}})密排面的原子堆垛出现错排而形成层错，为了降低体系的自由能，后续在(\mathrm{11}\overline{\mathrm{1}})密排面上堆垛的原子应以与该层错呈晶面对称的方式进行堆垛，以提高体系的对称性，降低体系能量，从而形成了Σ3孪晶界。

FGH96 alloy is a nickel-based superalloy that is commonly used in fabricating the turbine disks of aero engines owing of its excellent mechanical properties. Because the properties of nickel-based superalloys are determined based on their microstructure, researchers have been studying the evolution of microstructure in FGH96. However, most studies have focused on FGH96 superalloys that have undergone a hot isostatic pressing (HIP) process or a combination of HIP and hot isostatic forging. Recently, hot extrusion (HEX) has been widely used for manufacturing FGH96 superalloys; however, the research on alloys manufactured via HEX is scarce. In this study, FGH96 superalloys were solution heat-treated at temperatures ranging from 1100 ^oC to 1260 ^oC, and the evolution of their microstructure was analyzed via OM, EBSD, and TEM techniques. The mechanism of static recrystallization and the formation mechanism of Σ3 twin boundaries were also investigated. The results showed that the static recrystallization grain size and grain boundaries, including small angle boundaries, large angle boundaries, and Σ3 twin boundaries, were substantially influenced by the solution temperature. Furthermore, a distinct correlation existed between the microstructure evolution and solution temperature. The static recrystallization in the FGH96 alloy mainly occurs through the nucleation and growth of subgrains at temperatures ranging from 1100 ^oC to 1260 ^oC. During the static recrystallization process, a large number of stacking faults formed at the (\mathrm{11}\overline{\mathrm{1}}) close-packed plane, which improved the free energy. Therefore, to reduce the free energy, subsequent atoms were stacked symmetrically to the stacking faults, leading to the formation of Σ3 twin boundaries.