著者

齊藤 拓馬 原田 広史 横川 忠晴 大澤 真人 川岸 京子 鈴木 進補

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.86, no.9, pp.157-171, 2022-09-01 (Released:2022-08-25)

参考文献数

80

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Series of Ni-base single-crystal superalloys with superior thermal durability have been developed to improve thermal efficiency of gas turbine systems. Microstructural transition during creep so called “raft structure” formation enhances creep properties at lower stress and higher temperature condition. Furthermore, larger perfection degree of the raft structure contributes to better creep properties under the same creep condition. To control the perfection degree of the raft structure, magnitude of a lattice misfit and an elastic misfit between γ and γ′ phases should be controlled. In the current situation, the lattice misfit can be controlled by using alloy design program NIMS has developed. In this review, we focused on the role of the raft structure in alloy design. Observation results and predicted mechanisms about strengthening by the microstructural transition, in addition to the mechanism about microstructural transition itself during creep, were summarized and explained. Finally, under these recognitions mentioned above, our effort to establish a new alloy design approach to control the perfection degree of the raft structure by modifying the elastic misfit was introduced.

著者

木村 智人 鈴木 崇宣 小泉 裕 横川 忠晴 原田 広史 今井 八郎

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.71, no.11, pp.1041-1045, 2007 (Released:2007-11-02)

参考文献数

4

被引用文献数

8 9

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A post service examination of a turbine blade from a civil aeroengine has been carried out to ascertain the degree of microstructural coarsening and the distribution of crack damage induced during service. This was with the purpose to elucidate their correlation with the actual operating conditions. Samples were sectioned from different parts of the turbine blade for detailed examination by optical microscope and scanning electron microscope. The average length of cracks was used as one of the parameters to quantitatively illustrate the distribution of cracks on the turbine blade. Experimental results suggested that cracks were mainly concentrated on certain area of the pressure side. Leading edge of the suction side of the turbine blade consisted of mostly coarsened microstructure due to higher temperature exposure. In conclusions, there was no clear correlation between the crack damage distribution and the degree of microstructure evolution.

著者

横川 忠晴 谷 月峰 崔 傳勇 小泉 裕 藤岡 順三 原田 広史 福田 正 三橋 章

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.74, no.3, pp.221-225, 2010 (Released:2010-03-01)

参考文献数

18

被引用文献数

1 3

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New kinds of cast and wrought (C & W) Ni-Co base superalloys (TMW alloys) have been developed based on the innovative concept of combining two kinds of γ-γ′ two-phase alloys, Ni-base and Co-base alloys, for the applications of turbine disks and high-pressure compressor blades. The results based on testing 20 kg ingots indicate that TMW alloys show excellent high temperature strength and formability, may provide 50°C temperature advantage in 630 MPa/100 h creep performance over C & W alloy U720Li.    In this paper, we report our new results on the full-scale pancakes manufactured through the C & W process for real components. The results indicate that TMW alloys had good process-ability in the ingot making and forging into disk pancakes. Pancake disks with fine grain size of about 10 μm were successfully obtained for TMW alloys. TMW alloys provide 58°C to 76°C temperature advantages in 0.2% creep strain life under the 630 MPa condition, over alloy U720Li.