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Vol.56, No.10, 745 ~ 755, 2018
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| Title |
| Microstructural Evolution with Solidification Rate and Heat-Treatment of Single Crystal Superalloy CMSX-4 Grown using Seed |
| 권순철 Suncheol Kwon , 신종호 Jongho Shin , 임근영 Geunyoung Rim , 성기태 Gitae Sung , 윤병관 Byunggwan Yoon , 정의석 Euisuk Jung , 이재현 Jehyun Lee |
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| Abstract |
| The CMSX-4 superalloy including refractory elements was directionally solidified using the seed of a [001] single crystal to control the growth direction to [001], where solidification velocity was changed from 25 to 160 μm/s. In the log-log plot between spacing and solidification velocity, the primary dendrite arm spacing and secondary dendrite arm spacing linearly decreased with slopes of -0.288 and -0.318, respectively, as solidification velocity increased. A γ/γ′ eutectic structure was observed in the interdendritic region and the size linearly decreased with increasing solidification velocity. However, the volume fraction of the γ/γ′ eutectic structure did not change significantly with solidification velocity. Micro-segregation of the refractory elements was found in the primary dendrite arm region. These elements were not uniformly distributed even after solid-solution heat treatment, and an irregularly coarse γ′ -phase was observed in the interdendritic region after heat-treatment.
(Received July 11, 2018; Accepted August 16, 2018) |
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| Key Words |
| superalloy, directional solidification, seed, single crystal |
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