High-Temperature Structural Stabilities of Ni-Based SingleCrystal Superalloys Ni–Co–Cr–Mo–W–Al–Ti–Ta with Varying Co Contents
来源期刊：Acta Metallurgica Sinica2018年第2期
论文作者：Yu Zhang Qing Wang Hong-Gang Dong Chuang Dong Hong-Yu Zhang Xiao-Feng Sun
文章页码：127 - 133
摘 要：It has been recently pointed out that the compositions of industrial alloys are originated from cluster-plus-glueatom structure units in solid solutions. Specifically for Ni-based superalloys, after properly grouping the alloying elements into Al, Ni-like（■）, r-forming Cr-like（■） and c-forming Cr-like（■）, the optimal formula for single-crystal superalloys is established [Al–Ni12](Al1■<sub>0:5 ■1:5). The Co substitutions for Ni at the shell sites are conducted on the basis of the first-generation single-crystal superalloy AM3, formulated as [Al–■12Cox](Al1Ti0.25Ta0.25Cr1W0.25Mo0.25), with x = 1.5, 1.75, 2 and 2.5（the corresponding weight percents of Co are 9.43, 11.0, 12.57 and 15.71, respectively）. The900 ℃ long-term aging follows the Lifshitz–Slyozov–Wagner theory（LSW theory）, and the Co content does not have noticeable influence on the coarsening rate of c0. The microstructure and creep behavior of the four（001） single-crystal alloys are investigated. The creep rupture lifetime is reduced as Co increases. The alloy with the lowest Co（9.43 Co） shows the longest lifetime of about 350 h at 1050 ℃/120 MPa, and all the samples show N-type rafting after creep tests.
Yu Zhang1，Qing Wang1，Hong-Gang Dong1，Chuang Dong1，Hong-Yu Zhang2，Xiao-Feng Sun2
1. Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education2. Superalloys Division, Institute of Metal Research, Chinese Academy of Sciences
摘 要：It has been recently pointed out that the compositions of industrial alloys are originated from cluster-plus-glueatom structure units in solid solutions. Specifically for Ni-based superalloys, after properly grouping the alloying elements into Al, Ni-like（■）, r-forming Cr-like（■） and c-forming Cr-like（■）, the optimal formula for single-crystal superalloys is established [Al–Ni12](Al1■<sub>0:5 ■1:5). The Co substitutions for Ni at the shell sites are conducted on the basis of the first-generation single-crystal superalloy AM3, formulated as [Al–■12Cox](Al1Ti0.25Ta0.25Cr1W0.25Mo0.25), with x = 1.5, 1.75, 2 and 2.5（the corresponding weight percents of Co are 9.43, 11.0, 12.57 and 15.71, respectively）. The900 ℃ long-term aging follows the Lifshitz–Slyozov–Wagner theory（LSW theory）, and the Co content does not have noticeable influence on the coarsening rate of c0. The microstructure and creep behavior of the four（001） single-crystal alloys are investigated. The creep rupture lifetime is reduced as Co increases. The alloy with the lowest Co（9.43 Co） shows the longest lifetime of about 350 h at 1050 ℃/120 MPa, and all the samples show N-type rafting after creep tests.
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