(1. 西安科技大學(xué) 機械工程學(xué)院，西安 710054；
2. 西北工業(yè)大學(xué) 凝固技術(shù)國家重點實驗室，西安 710072)
摘 要: 借助光學(xué)顯微鏡(OM)、X射線衍射儀(XRD)、掃描電鏡(SEM)以及電子探針X射線顯微分析儀(EPMA)等方法，系統(tǒng)研究鎳基高溫合金電磁場下液相線等溫處理后的凝固組織與傳統(tǒng)鑄造組織析出相以及微觀偏析的差異、有無電磁場下不同溫度(1420 ℃、1400 ℃和1390 ℃)等溫處理后凝固組織。結(jié)果表明：電磁場下近液相線等溫處理后得到的組織為細(xì)小等軸晶，晶粒圓整度較好。與傳統(tǒng)鑄造組織相比，細(xì)晶鑄造組織中碳化物含量少于傳統(tǒng)鑄造組織的，且碳化物更為細(xì)小，分布更彌散。電磁場下近液相線等溫處理得到組織偏析系數(shù)更接近于1，微觀偏析較小。電磁場可通過均勻溫度場和溶質(zhì)場的方式使凝固組織細(xì)化。
關(guān)鍵字: 鎳基高溫合金；電磁場；近液相線；微觀偏析；等軸晶
（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
