(1. 西北工業(yè)大學 凝固技術(shù)國家重點實驗室，西安 710072；2. 西北工業(yè)大學 航空學院，西安 710072)
摘 要: 采用循環(huán)過熱與熔融玻璃凈化相結(jié)合的方法使K4169 高溫合金獲得了14~232 K過冷度。采用透射電子顯微鏡(TEM)、掃描電子顯微鏡(SEM)和光學顯微鏡等手段研究過冷K4169高溫合金枝晶形貌以及相組成。研究發(fā)現(xiàn)，枝晶形貌、晶粒尺寸和晶間相都會隨著過冷度的增加而發(fā)生明顯改變。同時，系統(tǒng)研究過冷K4169高溫合金凝固組織與力學性能之間的關(guān)系。實驗結(jié)果表明，晶粒尺寸和晶間相含量的減小以及Laves相的均勻分布提高了合金的抗拉強度和伸長率，并且當過冷度達232 K時，合金具有最優(yōu)力學性能，抗拉強度為932.2 MPa，伸長率為6.5%。
關(guān)鍵字: K4169高溫合金；深過冷；Laves相；力學性能；顯微組織
（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
