浇注温度对DD419单晶高温合金组织及持久性能的影响  

Effect of pouring temperature on microstructure and durability of DD419 single crystal superalloy

作　　者：张辉[1] 丁强 刘纪德[2] ZHANG Hui;DING Qiang;LIU Jide(Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education),Northeastern University,Shenyang 110819,China;Department of Superalloys,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]东北大学材料电磁过程研究教育部重点实验室,沈阳110819 [2]中国科学院金属研究所高温合金部,沈阳110016

出　　处：《航空材料学报》2025年第1期70-79,共10页Journal of Aeronautical Materials

基　　金：国家重点研发计划项目(2020YFA0714900)。

摘　　要：研究不同浇注温度的DD419单晶高温合金在850℃/650 MPa、1050℃/190 MPa、1100℃/130 MPa下的持久性能,并采用SEM、EDS和TEM分析不同浇注温度下的组织形态和成分偏析,研究其对持久性能的影响。结果表明:浇注温度降低,合金一次枝晶间距增大,共晶含量和显微孔洞增多,同时γ′相尺寸减小。在高温低应力(1100℃/130 MPa)下持久性能受γ′相尺寸的影响大于显微孔洞和残余共晶含量,细小弥散的γ′相有利于合金的持久性能,因此1500℃浇注的合金持久性能最佳。中温高应力下γ′相被大量位错切割,弥散的γ′相更利于位错塞积。同时不同浇注温度下的合金均保持了良好的伸长率,但随着浇注温度的降低,3种测试条件下的断面收缩率下降。浇注温度对合金的断口形貌影响不大,850℃/650 MPa持久断口附近的γ′相依旧保持立方形态,断裂机制为混合断裂,其他条件下γ′相均发生了筏化,断裂机制均为微孔聚集型断裂。The creep rupture properties of DD419 single crystal superalloys,fabricated at varying pouring temperatures were examined under conditions of 850℃/650 MPa,1050℃/190 MPa and 1100℃/130 MPa.SEM,EDS and TEM were used to analyze the microstructure and component segregation to study their effects on the durability.The results show that as the pouring temperature decreases,the primary dendrite spacing of the alloy widens,the eutectic content and the number of micropore increase,and the γ′phase size diminishes.Under high temperature/low stress(1100℃/130 MPa),the γ′phase size exerts a more pronounced influence on durability than do micropore and residual eutectic content.The finely dispersed γ′phase enhances the alloy’s durability under all three test scenarios,with the alloy poured at 1500℃exhibiting optimal durability.At intermediate temperature/high stress condition(1050℃/190 MPa),the γ′phase is intersected by numerous dislocations,and dispersed γ′phase may contribute to dislocation pile-ups.Concurrently,the alloy maintains good elongation at different pouring temperatures;however,as the pouring temperature decreases,section shrinkage decreases under all three test conditions.Pouring temperature has a negligible impact on the the alloy’s fracture morphology.Specifically,the γ′phase near the fracture surface of the specimen tested under 850℃/650 MPa condition remains cubic morphology,with a mixed-mode fracture mechanism.Under other durability parameters,the γ′phase assumes a rafted configuration,leading to an all-micropore aggregation fracture mechanism.

关 键 词：DD419 浇注温度 持久性能 显微孔洞 断裂机制 

分 类 号：V261.31[航空宇航科学与技术—航空宇航制造工程] TB332[一般工业技术—材料科学与工程]