Effect of thermal exposure at 1070℃ on microstructure of a single crystal superalloy

doi:10.13228/j.boyuan.issn10010963.20160234

Journal of Iron and Steel Research ›› 2017, Vol. 29 ›› Issue (3) : 235-240. DOI: 10.13228/j.boyuan.issn10010963.20160234

LIU Shizhong,SHI Zhenxue,LI Jiarong

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Abstract

The microstructure evolution of a nickel based single crystal after thermal exposure at 1070℃ for different time was investigated. The results show that the alloy consists of the regular and cube γ′ phase and γ phase after full heat treatment. The γ′ coarsening and the γ matrix channel broadening are observed after thermal exposure at 1070℃. There is no topological closepacked (TCP) phase precipited in matrix after thermal exposure for 200h. Needleshaped TCP phase precipitates in dendritic core of the alloy after thermal exposure for 400h. The microstructure of alloy presents full γ′ rafting structure after thermal exposure for 800h. With increasing thermal exposure time, the amount of TCP phase increases and it grows from the dendritic core to the interdendritic region. TCP phase consists of σ phase containing Re, W, Mo and Co, etc, and TCP phase precipitates and grows along fixed direction of ［012］σ∥［001］γ and (11-0)σ∥(22-0)γ.

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single crystal superalloy / microstructure stability / thermal exposure / TCP phase

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LIU Shizhong,SHI Zhenxue,LI Jiarong. Effect of thermal exposure at 1070℃ on microstructure of a single crystal superalloy[J]. Journal of Iron and Steel Research, 2017, 29(3): 235-240 https://doi.org/10.13228/j.boyuan.issn10010963.20160234

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