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In this paper, the calculation and experiments on solidification behavior were investigated in single crystal superalloys with different content of Ru. The solidification paths and phase composition were calculated by Scheil model in Thermo-Calc software.
The results calculated by Scheil model show that liquid, gamma, gamma prime, NiAl and P phase would occur sequentially during solidification, while the equilibrium phases calculated by Thermo-Calc software include liquid, gamma, gamma prime, mu, P-phase in single crystal superalloys with different content of Ru. The testing results show that the single crystal superalloys with different content of Ru were solidified with dendritic structure. Except for γ/γ' eutectics, some NiAl based β phase enriched in Ru element with blocky morphology formed in the interdendrtic region. With the increase of Ru, the amount of NiAl based b phase will be enlarged. During long term thermal exposure for 500 h, mu-phase with needle-like shape was found in these alloys. It was found that the transformation temperatures measured by DSC has the same tendency to the results calculated by Scheil model in Thermo-Calc software. |
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