A correlative multidimensional study ofγ’precipitates with Ta addition in Re-containing Ni-based single crystal superalloys  

作　　者：Jiachen Zhang Taiwen Huang Kaili Cao Jia Chen Huajing Zong Dong Wang Jian Zhang Jun Zhang Lin Liu 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Poly technical University,Xi'an,710072,PR China [2]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Shenyang,110016,PR China

出　　处：《Journal of Materials Science & Technology》2021年第16期68-77,共10页材料科学技术（英文版）

基　　金：the financial support by the National Natural Science Foundation of China(51631008);the National Key Research and Development Program of China(No.2016YFB0701400);Natural Science Foundation of Shaanxi Province2020JM-122。

摘　　要：The microstructural evolution in Re-containing Ni-based single crystal superalloys with different Tantalum(Ta)content(2 Ta,5 Ta and 8 Ta in wt%)was investigated.Ta addition significantly affected theγ’precipitate morphology,γ/γ’lattice misfit and microstructural stability during long-term aging.Results showed that the partitioning behaviors of solutes were enhanced by Ta addition,meanwhile,the reversal partitioning behavior of W was triggered which partitioned fromγ’precipitate to matrix.The elemental concentration redistribution caused variations in lattice misfit from positive to negative,the values of lattice misfit were measured to be 0.16%for 2 Ta alloy,then decreased to-0.07%for 5 Ta alloy and negatively increased to-0.23%for 8 Ta alloy.These variations in the lattice misfit were reflected on the transition ofγ’morphology from round-cornered cuboidal shape to cuboidal with sharp corners,accomplished with increasing shape parameter ratioη.Consequently,the optimalγ’shape could be obtained at lattice misfit of approximately 0.3%.Theγ’coarsening investigation at 900℃(up to 2000 h)indicated that Ta addition was beneficial for improving the microstructural stability by reducing the coarsening rate and interfacial energy,accompanied by the enhanced capability of resistingγ’coalescence.By incorporating the calculated interfacial energy,computational modeling,Thermo-Calc and PrecipiCalc,were employed to elucidate theγ’kinetic pathways,the simulation results agreed with experiments,indicating that the model and parameters were reasonable.Additionally,it was found that there was no overlap betweenγ’nucleation and coarsening when theγ/γ’interfacial energy increased to a critical value.

关 键 词：TANTALUM Ni-based superalloys Atom probe tomography Lattice misfit Coarsening kinetics 

分 类 号：TG132.3[一般工业技术—材料科学与工程]