【摘要】 采用Gleeble-3500热模拟试验机研究了核电站用Fe-Cr-Ni基合金热变形特征。利用电子背散射衍射（EBSD）技术研究了合金热变形微观组织演化规律。结果表明：流变应力曲线表现出典型的动态再结晶（DRX）特征。EBSD分析发现，DRX晶粒主要在晶界处形核长大。在1100℃/0.01 s^-1条件下发生完全DRX，晶粒明显细化。合金的主要形核机制是晶界弯曲形核。因此，核电站用Fe-Cr-Ni基合金的软化机制是动态恢复和DRX的结合。建立了具有应变补偿的Arrhenius本构模型。预测值与实验值的相关系数为0.9947。得到了临界应力（应变）和Z参数的可靠数学模型。DRX的临界应力（应变）随温度的降低或应变速率的增大而增大。通过Avrami模型建立了DRX动力学模型，并得到了典型的S型曲线。随着应变速率的降低和温度的升高，DRX的体积分数增加。更多还原

【Abstract】 Thermal deformation characteristics of Fe-Cr-Ni-based alloys for nuclear power plants were investigated using a Gleeble-3500 thermal simulation tester. The microstructure evolution law of alloy heat deformation was investigated using the electron backscatter diffraction（EBSD） technique. Results demonstrate that the flow stress curves show typical dynamic recrystallization（DRX） characteristics. According to EBSD analysis, the nucleation and growth of DRX grains are mainly at grain boundaries. The complete DRX occurs at 1100 ℃/0.01 s^-1 condition, and the grains are refined. The main DRX nucleation mechanism of the alloy is the grain boundary bowing nucleation. Therefore, the softening mechanism of Fe-Cr-Ni-based alloys for nuclear power plants is the combination of dynamic recovery and DRX. The Arrhenius constitutive model with strain compensation is developed. The correlation coefficient between the predicted and experimental values is 0.9947. The reliable mathematical model of critical stress（strain） and Z parameter is obtained. The critical stress（strain） of DRX increases as the temperature decreases or the strain rate increases. The DRX kinetic model is established by the Avrami model, and a typical S-type curve is obtained. As the strain rate decreases and the temperature increases, the volume fraction of DRX increases.更多还原