中文摘要：

采用真空感应熔炼法冶炼出镍基合金K4169,通过电解萃取结合原位SEM分析法研究夹杂物的物相组成、尺寸形貌及成分,并分析夹杂物的分布、来源及形成机理。结果表明：K4169合金中的单相夹杂物主要为氧化物、碳化物和氮化物（以TiN、Al2O3、SiO2、TiO2、SiC等为主）,复合夹杂物主要有硅铝酸盐（Al2O3-SiO2、Al2O3-MgO）、钛的碳、氮、氧化物（TiC-TiN、TiC-TiO2-TiN）及金属复合氧化物夹杂物（Mo-Ni-Fe-O、Ni-Nb-O）。TiN多分布在Laves相周围;SiC多分布在棒材边缘;其余各类氧化物多见于棒材心部缩孔内部及周围。硅铝酸盐复合夹杂物由硅铝氧化物的单相夹杂碰撞形成;金属复合氧化物夹杂于凝固后期的偏析液中氧化析出;碳氮化物复合夹杂物的形成机理有两类：一类为自发形核（TiC-TiN、TiC-TiO2-TiN）,另一类为以MgO-Al2O3为核心异质形核（TiN）。

英文摘要：

A method of electrolytic extraction combined with in-situ SEM analysis was utilized to characterize the inclusions in K4169 Ni-based superalloy prepared by vacuum induction melting （VIM）. The phases, compositions, morphologies, distribution and formation mechanism of the inclusions were analyzed by SEM in situ analysis. The results indicate that the inclusions of single phase in K4169 include mainly oxide, nitride and carbide（TiN, AL2O3, SiO2, TiO2 and SIC）. The inclusions of composite phases include mainly Al2O3-SiO2, A1203-MgO, TiC-TiN, TiC-TiO2-TiN, Mo-Ni-Fe-O and Nb-Ni-O. TiN inclusions mainly distribute near the Laves phase. SiC inclusions distribute in the edge of the cast ingots. Most oxide inclusions distribute in the shrinkage cavities which locate at the center of the cast ingots. The inclusions of Si and A1 oxides become a new aluminosilicate complex composition inclusion by chemical reaction or mechanical combination in K4169 by the VIM. The composite metal oxide inclusions are precipitated from liquid segregation oxidized during the solidification process. There are two types of nitride inclusions. The one is the TiC-TiN and TiC-TiO2-TiN inclusion which grow by means of spontaneous nucleation. The other one is MgO-Al2O3 which provide a heterogeneous nucleus for the growth of TiN. The composite metal oxide inclusions precipitated from liquid segregation are oxidized during the solidification process.