| Title |
Effects of Initial Nucleation Condition at the Start Block on the Grain Size and Growth Direction in Directionally Solidified CM247LC Superalloy |
| Authors |
윤혜영(Hye Young Yoon); 이재현(Je Hyun Lee); 정형민(Hyeong Min Jung); 서성문(Seong Moon Seo); 조창용(Chang Young Jo); 권석환(Seok Hwan Gwon); 장병문(Byeong Moon Chang) |
| DOI |
https://doi.org/10.3365/KJMM.2011.49.1.058 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
directional solidification; cooling condition; nucleation condition; EBSD; DSC; CM247LC |
| Abstract |
The grain size and growth direction of a directionally solidified turbine blade were evaluated by the initial nucleation condition at the start block of directional solidification. The initial nucleation condition was controlled by inserting a Ni foil on the directional solidification plate of the directional solidification furnace. Fine grains with good orientation were obtained in the faster cooling condition at the start block. The nucleus number was compared with the cooling rate of the start block by electron back scattered diffraction (EBSD). DSC (differential scanning calorimeter) analysis was performed to compare the melting point and undercooling for nucleation of the coarse nuclei and fine nuclei of the start block. The faster cooling condition at the start block showed more undercooling for nucleation and smaller size of nuclei which resulted in a fine grain with good orientation in the directional turbine blade. |