(1. 西北工业大学 凝固技术国家重点实验室，西安 710072；2. 西北工业大学 航空学院，西安 710072)
摘 要: 采用循环过热与熔融玻璃净化相结合的方法使K4169 高温合金获得了14~232 K过冷度。采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)和光学显微镜等手段研究过冷K4169高温合金枝晶形貌以及相组成。研究发现，枝晶形貌、晶粒尺寸和晶间相都会随着过冷度的增加而发生明显改变。同时，系统研究过冷K4169高温合金凝固组织与力学性能之间的关系。实验结果表明，晶粒尺寸和晶间相含量的减小以及Laves相的均匀分布提高了合金的抗拉强度和伸长率，并且当过冷度达232 K时，合金具有最优力学性能，抗拉强度为932.2 MPa，伸长率为6.5%。
关键字: K4169高温合金；深过冷；Laves相；力学性能；显微组织
（1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
2. School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:Various undercoolings 14-232 K of bulk K4169 superalloys were obtained by the method of molten glass fluxing combined with superheating cycling and the mechanical properties of undercooled K4169 with as-solidified state were tested. Microstructures and phases composition in undercooled bulk K4169 superalloy were identified by transmission electron microscope (TEM), scanning electron microscope (SEM) and optical microscopy (OM). The morphology of dendrites, grain size and intergranular phase all change with the increased undercooling. Meanwhile, the relationship between microstructure of undercooled K4169 superalloy and tensile properties was investigated. The experimental results show that the uniform distribution of Laves phase and the decrease of grain size and intergranular phase content are favorable for the improvement of mechanical properties. The maximum tensile strength and elongation obtained at undercooling of 232 K are 932.2 MPa and 6.5 %, respectively.
Key words: K4169 superalloy; undercooling; Laves phase; mechanical properties; microstructures
