(1. 西安科技大学 机械工程学院，西安 710054；
2. 西北工业大学 凝固技术国家重点实验室，西安 710072)
摘 要: 借助光学显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)以及电子探针X射线显微分析仪(EPMA)等方法，系统研究镍基高温合金电磁场下液相线等温处理后的凝固组织与传统铸造组织析出相以及微观偏析的差异、有无电磁场下不同温度(1420 ℃、1400 ℃和1390 ℃)等温处理后凝固组织。结果表明：电磁场下近液相线等温处理后得到的组织为细小等轴晶，晶粒圆整度较好。与传统铸造组织相比，细晶铸造组织中碳化物含量少于传统铸造组织的，且碳化物更为细小，分布更弥散。电磁场下近液相线等温处理得到组织偏析系数更接近于1，微观偏析较小。电磁场可通过均匀温度场和溶质场的方式使凝固组织细化。
关键字: 镍基高温合金；电磁场；近液相线；微观偏析；等轴晶
（1. School of Mechanical Engineering, Xi’an University of Science and Technology, Xi’an 710054, China;
2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:The differences of macrostructure, microstructure, precipitate and microsegregation of solidification structure by isothermal treatment near the liquids in electromagnetic field and traditional casting of Ni-based superalloy were investigated by optical microscope (OM), X-ray diffractometer (XRD), scanning electron microscopy (SEM) and electron probe X-ray microanalyzer (EPMA). The results show that the microstructure is small and uniform equiaxed grain by isothermal treatment near the liquidus and electromagnetic field. Compared with traditional microstructure, the content of carbide in fine grained casting is less than that of traditional casting, and the carbide is smaller and more dispersed than that of traditional casting. The segregation coefficient of the microstructure by isothermal treatment near the liquidus and electromagnetic field is closer to 1. The electromagnetic field can refine microstructure by making the temperature field and the solute field become more uniform.
Key words: Ni-based superalloy; electromagnetic field; near liquidus; microsegregation; equiaxed grain
