Nucleation and transition sequences of TCP phases during heat-exposure in a Re-containing Ni-based single crystal superalloy  

作　　者：Chen Liu Wenchao Yang Jiarun Qin Pengfei Qu Haitao Fu Qiang Wang Jun Zhang Lin Liu 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China

出　　处：《Journal of Materials Science & Technology》2024年第35期165-173,共9页材料科学技术(英文版)

基　　金：supported by the National Natural Science Foundation of China(Nos.51771148,52071263,52031012,and 52322410);the Science Center for Gas Turbine Project(No.P2021-A-IV-001-001);the Key Research and Development Program of Shaanxi Province(No.2023-YBGY-432);the Natural Science Ba-sic Research Plan in Shaanxi Province of China(No.2021JC-13);the Science and Technology Funding Key R&D Industry Foresight and Key Technologies of Jiangsu Province(No.BE2022124);the Re-search Fund of the State Key Laboratory of Solidification Processing(NPU),China(No.2021-QZ-03).

摘　　要：The nucleation and transition sequences of topologically close-packed(TCP)phases in a Re-containing Ni-based single crystal superalloy were systematically investigated using in-situ transmission electron microscopy(TEM)and three-dimensional atom probe technology(3D-APT).During the initial stage of heat-exposure at 1100℃,the TCP phase forming elements(Re,Co,Cr,etc.)segregated at theγ/γin-terface near theγmatrix side to provide the concentration undulations for the nucleation sites of TCP phases,following which theσand P phase coherently nucleated along the(111)γand(022)γplanes from theγ/γinterface near theγmatrix side,respectively.With prolonged heat-exposure time,transitions fromσphase to P phase,σphase toμphase,and P phase toμphase occurred.Besides,the orientation relationships of TCP phase intergrowth structures indicated that the P phase grew along the(¯101)σplane of theσphase by co-lattice precipitation,meanwhile,theμphase grew with smaller lattice misfits along the(0¯40)σplane of theσphase and the(400)P plane of the P phase.Additionally,the result by first-principles calculation evidenced that theμphase had the lowest system energy to make the transition ofσphase and P phase toμphases inevitable,therefore,the TCP phase ultimately existed as the most stableμphase.Finally,the transition sequences of TCP phase during heat-exposure could be summarized into three types:γmatrix→σ→μ,γmatrix→P→μ,andγmatrix→σ→P→μ.

关 键 词：Ni-based single crystal superalloy TCP phase NUCLEATION INTERGROWTH 

分 类 号：TG1[金属学及工艺—金属学]