Phase-field simulation of Suzuki segregation in Co-Ni-based superalloy with Nb-addition

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• 作者：Yuichiro Koizumi ; Shou Suzuki ; Takuma Otomo ; ^{takuma.otomo@sii.co.jp} ; Shingo Kurosu ; Yunping Li ; Hiroaki Matsumoto ; Akihiko Chiba
• 关键词：Suzuki effect ; Phase-field method ; Co&ndash ; Ni-based alloy ; Stacking fault ; B. Strain-aging
• 刊名：Intermetallics
• 出版年：2012
• 期刊代码：36_09669795
• 类别：ms
• 出版时间：August, 2012
• 卷：27
• 期：Complete
• 页码：52-57
• 文件大小：811 K

摘要

In this study, segregation at stacking faults (SFs) in a Co-Ni superalloy with the composition of Co-33Ni-20Cr-10Mo-xNb [wt%] (x聽=聽0,1,2) has been investigated by phase-field simulation for clarifying the roles of each element in the Suzuki effect which is believed to be responsible for strain-aging. The simulation result suggested that Ni-depletion can be very significant in the absence of Nb, and the deviation in concentration can exceed 4聽wt%. The stacking fault energy (SFE) was decreased from 35聽mJ/m² to聽鈭?75聽mJ/m² as a result of the segregation. Nb-addition enhanced the Cr-segregation significantly, however, it resulted in increase in SFE although the strain-aging can be enhanced by Nb-addition. The reasons for the discrepancy are discussed from the viewpoint of the effect of Nb-addition on the kinetics and energetics of Cr-segregation.