CM247LC 초내열합금에서 일방향응고에 따른 응고조직 변화

• Published in: 대한금속·재료학회지, 54(11) Vol. 54; no. 11; pp. 838 - 845
• Main Authors: 이정석, Jeongseok Lee, 권석환, Seokhwan Kown, 윤병관, Byunggwan Yoon, 장병문, Byungmoon Chang, 정연길, Yongil Jung, 이재현, Jehyun Lee
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 05.11.2016; 대한금속·재료학회
• Subjects: electron backscattering diffraction(EBSD); Ni base superalloy; solidification; 재료공학
• DOI: 10.3365/KJMM.2016.54.11.838
• ISSN: 1738-8228

Directional solidification of CM247LC was performed at a constant growth velocity (300 mm/h) using a Bridgman type furnace. Microstructural features, including the number of grains, PDAS, and EBSD IPF map, were investigated with progressive positions from the starter block. As directional solidification proceeded, the number of grains decreased and PDAS increased. These results indicate that the thermal gradient decreases with distance from the starter block. Thermal gradient changes were estimated by dendrite spacing change in the directionally solidified rod. The EBSD IPF map showed that almost all of the grains were close to the < 001 > preferred direction, but with heights of about 300 mm from the starter block, some grains at the center of the specimen exhibited quite different crystallographic directions near the gate instead of the preferred direction. (Received October 5, 2015; Accepted May 24, 2016)