| Title |
Microstructural Evolution with Solidification Rate and Heat-Treatment of Single Crystal Superalloy CMSX-4 Grown using Seed |
| Authors |
권순철(Suncheol Kwon); 신종호(Jongho Shin); 임근영(Geunyoung Rim); 성기태(Gitae Sung); 윤병관(Byunggwan Yoon); 정의석(Euisuk Jung); 이재현(Jehyun Lee) |
| DOI |
https://doi.org/10.3365/KJMM.2018.56.10.745 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
superalloy; directional solidification; seed; single crystal |
| 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) |