Isothermal compression of HIPed (Hot Isostatic Pressed) FGH4096 superalloy in the temperature range 1080 ～ 1140℃ and strain rate range 0.02 ～ ls -1 with deformation from 15％ to 50％ have been conducted on Gleeble-1500D simulator, Recrystallization nucleation and microstructure evolution during the hot deformation have been revealed by TEM (transmission electron microscopy) and MO( metallographie observation). When compressed with the deformation of 35％ or blow, a not fully recrystallized mierostrueture called "Link" microstructure received. Fully recrystallized microstructure obtained when the deformation reached 50％, grain size of which grows as the temperature rise and strain rate decrease. Primary recrystallization nucleation sites could be summarized as follows:PPB (Previous Particle Boundaries), grain boundaries of the recrystallized grain and twin sourse. A fine structure with average 8rainsize of 4p, m obtained by the effect of multiaxial hot deformation as a result.%使用Gleeble-1500D热模拟试验机对热等静压态FGH4096合金进行变形温度1080～1140℃,应变速率0.02～1s-1,变形量15%,35%和50%的等温压缩实验.通过观察微观组织,分析了粉末高温合金动态再结晶的组织演化规律,并通过透射电镜研究了再结晶的形核位置.当变形量在35%及以下时,得到不完全再结晶组织,即"项链"组织;当变形量大于50%时,得到完全的动态再结晶组织.动态再结晶晶粒尺寸随变形温度的升高和应变速率的降低而增大.再结晶形核主要在以下三个位置,即原始颗粒边界,再结晶晶粒边界以及孪晶源.最后利用多方向热变形对晶粒的破碎和细化,得到平均品粒尺寸为4μm的细晶坯料.
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