Tailoring Microstructure and Microsegregation in a Directionally Solidified Ni-Based SX Superalloy by a Weak Transverse Static Magnetic Field  

作　　者：Yong Zhao Haijun Su Guangrao Fan Chenglin Liu Taiwen Huang Wenchao Yang Jun Zhang Lin Liu Hengzhi Fu 

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

出　　处：《Acta Metallurgica Sinica(English Letters)》2022年第7期1164-1174,共11页金属学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.51690163,52130204,52174376,51822405);the Science and Technology Innovation Team Plan of Shaan Xi Province(No.2021TD-17);the Joint Research Funds of the Department of Science&Technology of Shaanxi Province and NPU(No.2020GXLH-Z-024);the Fundamental Research Funds for the Central Universities(No.D5000210902);the Key R&D Program of ShaanXi Province(No.2019ZDLGY 04-04);the Research Fund of the State Key Laboratory of Solidification Processing(NPU)(No.2019-QZ-02)。

摘　　要：A weak transverse static magnetic field(WTSMF,0–0.5 T)is applied to the directional solidification process of a DD3 Ni-based SX superalloy,aiming to tailor the microstructure and microsegregation of alloys.The mechanisms of microstructural refinement and microsegregation distribution caused by a WTSMF during directional solidification are discussed.It is shown that the primary dendrite arm spacing is rapidly reduced from 181 to 143μm,and the average size ofγ′phase is significantly refined from 0.85 to 0.25μm as the magnetic field increases from 0 to 0.5 T.At the same time,the volumefractions ofγ/γ′eutectic and the segregation coefficient are also gradually decreased.The 3D numerical simulations of the multiscale convection in liquid phase show that the modifications of the microstructure and microsegregation in DD3 are mainly attributed to the enhanced liquid flow caused by thermoelectric magnetic convection(TEMC)at dendrite/sample scale under the WTSMF.The maximum of the TEMC increases with increasing the magnetic field intensity.This work paves a simple way to optimize the microstructure and microsegregation in directionally solidified Ni-based SX superalloys without changing the processing parameters and composition.

关 键 词：Transverse static magnetic field MICROSTRUCTURE Segregation coefficient Ni-based single-crystal superalloy Thermoelectric magnetic convection 

分 类 号：TG132.3[一般工业技术—材料科学与工程]