Two experimental alloys containing different contents of Ru were investigated to study the effect of Ru on the microstructural evolution during long-term thermal exposure. The increase in Ru promoted the formation of cubical, tiny, and even γ′ phase after full heat treatment. Moreover, the samples after full heat treatment were exposed at 1100 °C for different time. Based on the classical model by Lifshitz, Slyozov, and Wagner, the coarsening of γ′ phase of the alloy containing 2.5 and 3.5 wt.% Ru during the long-term aging was controlled by the interface reaction and diffusion, respectively. The γ/γ′ lattice misfit was more negative with the increment of Ru addition, which induced the formation of stable rafted γ′ phase in the alloy containing 3.5 wt.% Ru at the initiation of long-term aging. Besides, the increase in Ru reduced the diffusion coefficient, which could restrain the γ′ phase coarsening. The lower γ/γ′ lattice misfit of the alloy containing 2.5 wt.% Ru promoted the interface reaction, which induced the rapid coarsening of γ′ phase. Therefore, the increase in Ru improved the microstructural stability of the alloys. On the other hand, the raise of Ru induced “reverse partitioning” behavior, which was effective in suppressing the emergence of the topologically close-packed phase (TCP phase). The TCP phase occasionally occurred in the alloy containing 2.5 wt.% Ru, which was attributed to the high temperature and the supersaturation of the γ matrix. Moreover, the TCP phase was determined as μ phase, which had a high concentration of Co, Re, Mo, and W. A sketch map describing the evolution of the TCP phase was also constructed.

研究了两种含Ru含量不同的实验合金，以研究Ru对长期热暴露过程中微观组织演变的影响。充分热处理后，Ru的增加促进了立方相，微小相，甚至γ ′相的形成。此外，将完全热处理后的样品在1100°C下暴露不同的时间。根据Lifshitz，Slyozov和Wagner的经典模型，在长期老化过程中，含2.5和3.5 wt％的Ru的合金的γ '相的粗化分别通过界面反应和扩散来控制。的γ / γ '晶格错配是更负的与钌添加的增量，从而诱发稳定筏形成γ长期时效开始时，合金中含有3.5 wt。％Ru的′相。另外，Ru的增加降低了扩散系数，这可以抑制γ ′相的粗化。含2.5％（重量）Ru的合金较低的γ / γ ′晶格失配促进了界面反应，从而引起γ的快速粗化'相。因此，Ru的增加改善了合金的微观结构稳定性。另一方面，Ru的增加引起“反向分配”行为，这在抑制拓扑紧密堆积阶段（TCP阶段）的出现方面是有效的。在含2.5％（重量）Ru的合金中偶尔会出现TCP相，这归因于高温和γ基过饱和。此外，TCP相被确定为μ相，其中Co，Re，Mo和W的浓度很高。还绘制了描述TCP相演变的示意图。