Role of Ru on the Microstructural Evolution During Long-Term Aging of Ni-Based Single Crystal Superalloys
来源期刊：Acta Metallurgica Sinica2020年第12期
论文作者：Wei Song Xin-Guang Wang Jin-Guo Li Ye-Shun Huang Jie Meng Yan-Hong Yang Jin-Lai Liu Ji-De Liu Yi-Zhou Zhou Xiao-Feng Sun
摘 要：Two experimental alloys containing diff erent contents of Ru were investigated to study the eff ect 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 diff erent time.Based on the classical model by Lifshitz, Slyozov, and Wagner, the coarsening of γ′ phase of the alloy containing 2.5 and3.5 wt.% Ru during the long-term aging was controlled by the interface reaction and diff usion, respectively. The γ/γ′ lattice misfi t 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 diff usion coeffi cient,which could restrain the γ′ phase coarsening. The lower γ/γ′ lattice misfi t 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 eff ective 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.
Wei Song，Xin-Guang Wang，Jin-Guo Li，Ye-Shun Huang，Jie Meng，Yan-Hong Yang，Jin-Lai Liu，Ji-De Liu，Yi-Zhou Zhou，Xiao-Feng Sun
Superalloys Division,Institute of Metal Research ,Chinese Academy of Sciences
摘 要：Two experimental alloys containing diff erent contents of Ru were investigated to study the eff ect 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 diff erent time.Based on the classical model by Lifshitz, Slyozov, and Wagner, the coarsening of γ′ phase of the alloy containing 2.5 and3.5 wt.% Ru during the long-term aging was controlled by the interface reaction and diff usion, respectively. The γ/γ′ lattice misfi t 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 diff usion coeffi cient,which could restrain the γ′ phase coarsening. The lower γ/γ′ lattice misfi t 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 eff ective 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.
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