Effect of cobalt on chemical segregation and solution process in Re-containing single crystal superalloys

• Published in: Transactions of Nonferrous Metals Society of China Vol. 16; no. A03; pp. 1978 - 1981
• Main Author: 王文珍 金涛 赵乃仁 王志辉 孙晓峰 管恒荣 胡壮麒
• Format: Journal Article
• Language: English
• Published: Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China 01.12.2006; School of Graduate, Chinese Academy of Sciences, Beijing 100039, China%Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
• Subjects: 化学偏析; 单晶高温合金; 有色金属; chemical segregation; single crystal superalloy; cobalt
• ISSN: 1003-6326

The effect of cobalt on chemical segregation and solution process in three nickel base single crystal superalloys was investigated. Three alloys containing the mass fi＇action of cobalt of 12% （named Alloy 1 ）, 3% （named Alloy 2） and 0 （named Alloy 3）, respectively were studied, in which the contents of other elements were same. The results show that the segregation extent of W, Re, Ta, Al between dendrite and interdendritic region rises with the increase of cobalt content. The incipient melting points decrease by 10 ℃ and 20 ℃ respectively when the content of cobalt increases from 0 through 3% to 12%. During solid solution at 1 340 ℃, the solid solution of large gamma prime in interdendritic region and the dissolution of eutectic in alloy 1 become easier than in other two alloys. After heat-treatment at 1 340℃ for 8 h, the segregation extent of elements in alloy 1 decreases dramatically, while in alloy 2 and alloy 3, the segregation ratios decrease slowly. It suggests that the higher content of cobalt can accelerate the diffusion process at high temperature.