준안정 액상의 상분리에 미치는 냉각속도의 영향 = The Effect of Cooling Rate on Metastable Liquid Phase Separation

다국어 초록 (Multilingual Abstract)

The effect of cooling rate on the metastable liquid phase separation(MLPS) in Cu-Fe binary and Cu-Fe-Co ternary alloys was investigated using an electromagnetic levitation technique. The cooling rate during phase separation was controlled by dropping the specimens to copper substrate which was in 15 ㎝ apart from levitation coil. The cooling rate in levitation state was 5-20 Ｋ/sec, and those of free falling and after splash were 130 Ｋ/sec and 2300 Ｋ/sec respectively. In the specimen solidified at medium cooling rate(about 130 Ｋ/sec), secondary phase separation was observed in both L1(Fe- or Fe, Co-rich phase) and L2(Cu-rich phase) phases that have been formed by primary phase separation. In this case the phase separation occured by nucleation and growth. Spinodal decomposition is considered as a dominent phase separation mechanism in L1 droplets solidified at fast cooling rate (about 2300 K/sec). There was no evidence of spinodal decomposition in L2 phase.

목차 (Table of Contents)

• 1. 서론
• 2. 실험 방법
• 3. 결과
• 냉각속도 변화
• 상분리 조직
• 4. 고찰
• 냉각속도가 중간(95-152 K/sec) 일 때의 상분리-자유 낙하 과정에서의 MLPS
• 냉각속도가 빠를 때(2360K/sec)의 상분리-충돌후의 MLPS
• 5. 결론