【摘要】 探究了一级时效热处理温度对两种不同成分镍基单晶高温合金微观组织退化及拓扑密堆相（TCP相）析出行为的影响。结果表明，随着一级时效热处理温度的升高，两种合金中γ′相的尺寸均呈现增大的趋势，而γ′相的体积分数先增大后减小，并在温度为1 100℃时达到峰值。此外，随着温度的升高，γ′强化相的立方度逐渐提升，但其边缘开始出现回溶现象，同时基体通道逐渐拓宽。在难熔元素总量较高的合金中，当一级时效热处理温度为1 140℃时，γ基体通道中出现了细小的二次γ′相；且由于长时间的热暴露，合金中的γ′相开始粗化，形成筏形组织。此外，合金中逐渐析出有害TCP相，且随着温度的升高，TCP相的数量逐渐增多。而在难熔元素总量较低的合金中，未观察到TCP相的析出，γ′相的粗化-筏化过程及基体通道宽化过程减缓，表明该合金具有更加优异的组织稳定性。更多还原

【Abstract】 The effect of primary aging treatment temperature on microstructure degradation and formation of topological close-packed phases(TCP phases) in two Ni-based single crystal superalloys with various element compositions was studied. The results showed that with the increase of primary aging treatment temperature, the γ′ phase size of two alloys exhibited the increasing trend. Additionally, the γ′ phase volume fraction initially increased and subsequently decreased as the primary aging treatment temperature increased, both reaching the peak at 1 100 ℃. As the temperature increased, the γ′ phase exhibited better cubic shape.However,the resolution at the edge of γ′phase occurred,which also resulted in the extension in the width of γ phase channel.In the alloy with higher content of refractory elements,formation of secondaryγ′phase could be observed in the γ channel at 1 140℃.Meanwhile,the γ′phase started to coarsen due to the prolonged thermal exposure,forming rafted γ′phase structure.In addition,TCP phase gradually formed during the primary aging treatment,and the content of harmful TCP phase increased as the temperature increased.While,in the alloy with lower refractory elements,formation of TCP phase was not observed,coarsen-raft process and extension in the width of γ channel were slowed and delayed,which indicated the better microstructure stability.更多还原