Inconsistent creep between dendrite core and interdendritic region under different degrees of elemental inhomogeneity in nickel-based single crystal superalloys

Wanshun Xia ¹Xinbao Zhao ¹Liang Yue ¹Quanzhao Yue ¹Jiangwei Wang ²Qingqing Ding ¹Hongbin Bei ¹Ze Zhang¹

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作者信息

1. Institute of Superalloys Science and Technology,School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,China
2. Zhejiang Univ,Ctr Electron Microscopy,Hangzhou 310027,China
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Abstract

The creep inconsistency between dendrite core and interdendritic region is investigated in a nickel-based single crystal superalloy under 1373 K and 137 MPa.Two specimens with higher and lower degree of el-emental inhomogeneity on dendritic structures are compared.For specimen with higher inhomogeneity,stronger segregation of refractory elements reinforces the local strength in dendrite core,but damages the strength in interdendritic region.Creep strain is accumulated faster in interdendritic region giving rise to promoted dislocation shearing in γ'phase,faster degradation of dislocation networks and facili-tated topological inversion of rated structures.Although the segregation of refractory elements produces a high density of topologically close-packed(TCP)phase in dendrite core,faster accumulation of creep strain forms microcracks prior in interdendritic region that gives rise to final rupture of the specimen.In another specimen,increased solid solution time gives rise to overall reduced inhomogeneity.Creep in-consistency is relieved to show more uniform evolution of dislocation substructures and rafting between dendrite core and interdendritic region.The second specimen is ruptured by formation and extension of microcracks along TCP phase although the precipitation of TCP phase is relatively restricted under re-duced inhomogeneity.Importantly,the balance of local strength between dendrite core and interdendritic region results in over 40％increase of creep rupture life of the second specimen.

Key words

Nickel-based single crystal superalloys/Dendritic structure/Inhomogeneity/Creep/Rafting/Dislocation networks

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基金项目

National Natural Science Foundation of China(91960201)

National Natural Science Foundation of China(51988101)

Key Basic Research Program of Zhejiang Province(2020C01002)

Zhejiang Provincial Natural Science Foundation of China(LY20E010004)

Fundamental Research Funds for the Central Universities(2019QNA4012)

Innovation Fund of the Zhejiang Kechuang New Materials Research Institute(ZKN-18-Z01)

supports of equipment and guidance of experiments of researchers in Centre of Electron of Microscopy of Zhejiang University()

出版年

2021

材料科学技术(英文版)

中国金属学会中国材料研究学会中国科学院金属研究所

材料科学技术(英文版)

CSTPCDCSCDSCI

影响因子：0.657

ISSN：1005-0302

参考文献量84

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