【摘要】 采用Thermo-Calc热力学模拟软件，计算了Nimonic 80A合金中不同元素含量的平衡相图，分析平衡状态下合金主要元素对析出相种类、析出温度和析出含量的影响。为验证热力学计算的可靠性，采用SEM、TEM、XRD等分析方法，对时效态合金试样进行组织特征与定性、定量分析。结果表明，Nimonic 80A合金的平衡析出相为γ、γ′、M₂₃C₆、MX和M₇C₃相。降低C含量，既能提高M₇C₃相的析出温度，又能促进γ′相的析出量；提高Al、Ti含量使M₇C₃、γ′和M₂₃C₆相的析出温度升高，促进了γ′和M₂₃C₆相的析出，其中单一Al元素的影响要高于Ti元素；提高Ti+Al总含量使M₂₃C₆与γ′相的析出温度升高，γ′相析出含量显著增加；Ti/Al比的增加使γ′相的析出含量逐渐降低。在1060℃×8 h空冷+845℃×24 h空冷+700℃×16 h空冷双时效工艺下，M₇C₃、M₂₃C₆与γ′相大量析出，其不同尺寸γ′相加强了合金的析出强化，碳化物加强了合金的晶界强化，在规定合金成分范围内内，C含量取下限（0.05%～0.075%）,Al含量取中限（1.3%～1.6%）,Ti含量取上限（2.3%～2.7%）,Ti+Al总量取上限（3.65%～4.46%）,Ti/Al比取中限（1.76）可获得良好的析出相成分配比。更多还原

【Abstract】 Variation of equilibrium phases with temperature of Nimonic 80A alloy with different element contents was calculated by Thermo-Calc thermodynamic simulation software, and the effects of main elements on the types of precipitates, precipitation temperature and precipitation content were analyzed. In order to verify the reliability of thermodynamic calculation, the microstructure characteristics, qualitative and quantitative analysis of aged alloy samples were carried out by means of SEM, TEM, XRD and so on. The results show that the equilibrium precipitates of Nimonic 80A alloy are γ, γ′, M₂₃C₆, MX and M₇C₃ phases. Decreasing C content cannot only increase the precipitation temperature of M₇C₃ phase, but also promote the precipitation amount of γ′phase; increasing the content of Al and Ti increases the precipitation temperature of M₇C₃, γ′ and M₂₃C₆ phases, and promotes the precipitation of γ′and M₂₃C₆ phase, in which the effect of single Al element is higher than that of Ti element; increasing the total content of Ti+Al increases the precipitation temperatures of M₂₃C₆ and γ′ phases, and the precipitation content of γ′ phase increases significantly. With the increase of Ti/Al ratio, the precipitation content of γ′ phase decreases gradually. Under 1060 ℃×8 h air cooling, 845 ℃×24 h air cooling and 700 ℃×16 h air cooling double aging process, a large number of M₇C₃, M₂₃C₆ and γ′ phases are precipitated. The γ′ phases of different sizes strengthened the precipitation strengthening of the alloy, and the carbides strengthened the grain boundary strengthening of the alloy. Within the prescribed range of alloy composition, the lower limit of C content（0.05%-0.075%）, the middle limit of Al content（1.3%-1.6%） and the upper limit of Ti content（2.3%-2.7%） were selected. The upper limit of the total amount of Ti+Al（3.65%-4.46%） and the middle limit of the specific content of Ti/Al（1.76） can obtain a good distribution ratio of precipitated phase.更多还原