摘要
The effect of cobalt on chemical segregation and solution process in three nickel base single crystal superalloys was investigated. Three alloys containing the mass fraction 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.
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.
出处
《中国有色金属学会会刊:英文版》
CSCD
2006年第A03期1978-1981,共4页
Transactions of Nonferrous Metals Society of China
关键词
钴
单晶高温合金
化学偏析
有色金属
single crystal superalloy
cobalt
chemical segregation