摘要
A new insight into the microstructural stability was proposed in Ni-based single crystal superalloys with Ru addition,and the element segregation behavior atγ/γ′interface was investigated by three-dimensional atom probe technology(3D-APT).After standard heat treatment,it was found that Ru addition barely altered the element partitioning coefficient betweenγmatrix andγ′phase,and no element-segregation layer was observed atγ/γ′interface.During the heat exposure at 1100°C,Ru addition obviously promoted the rafting of theγ′precipitates and inhibited the precipitation of topological close-packed(TCP)phases.It was more important that an element-segregation layer containing Re,Co,and Cr was formed in theγmatrix close to theγ/γ′interface due to an“uphill diffusion”effect,and its concentration was obviously reduced after Ru addition.Finally,the microstructural stability based on the element segregation behavior atγ/γ′interface was discussed.This element-segregation layer increased theγ/γ′interfacial energy by increasing the absolute value of the lattice misfit ofγ/γ′interface to promote the rafting of theγ′precipitates after Ru addition.On the other hand,the decrease of the segregation concentration of Re,Co,and Cr elements as TCP phase-forming elements near theγ/γ′interface due to a“reverse partitioning”effect inhibits the precipitation of TCP phases in Ni-based single crystal superalloys after Ru addition.
基金
funded by the National Science and Technol-ogy Major Project(Nos.2017-VI-0002-0072,2019-VI-0020-0135)
the National Natural Science Foundation of China(Nos.51771148,52071263,52031012)
the Key Research and Development Program of Shaanxi Province(Nos.2020ZDLGY13-02,2023-YBGY-432)
the Natural Science Basic Research Plan in Shaanxi Province of China(No.2021JC-13)
the Research Fund of the State Key Labora-tory of Solidification Processing(NPU),China(No.2021-QZ-03).
