两种高代次镍基单晶高温合金热机械疲劳中的再结晶行为  

Recrystallization During Thermo-Mechanical Fatigue of Two High-Generation Ni-Based Single Crystal Superalloys

作　　者：赵鹏 谢光[3] 段慧超[1] 张健 杜奎[1] ZHAO Peng;XIE Guang;DUAN Huichao;ZHANG Jian;DU Kui(Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China;Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所沈阳材料国家研究中心,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016 [3]中国科学院金属研究所师昌绪先进材料创新中心,沈阳110016

出　　处：《金属学报》2023年第9期1221-1229,共9页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.91960202,52171020,51901229,51911530154,91860201和52271042;国家科技重大专项项目No.P2022-C-IV-001-001。

摘　　要：通过SEM和TEM等手段研究了经热机械疲劳变形后的第三代和第四代单晶高温合金的显微组织,了解高温合金在近服役条件下的变形组织,分析单晶高温合金近服役条件下的变形机制。结果表明,第三代和第四代单晶高温合金样品中在不同{111}面上产生了大量的变形孪晶,且在平行的孪晶片层中或者孪晶片层交截周围发现大量再结晶晶粒。再结晶晶粒的界面主要由变形后的孪晶界、小角度晶界以及孪晶相交产生的大角度晶界组成。借助像差校正透射电镜解析了变形后的孪晶界结构以及孪晶诱发动态再结晶的过程,揭示了单晶高温合金热机械疲劳断裂机制。Ni-based single crystal superalloys are widely used for turbine engine blades because of their excellent high-temperature mechanical properties.Thermo-mechanical fatigue(TMF) is a complex deformation process that combines strain and temperature effects.This process is also considered as a deformation method related to the working conditions of aviation turbine blades.Therefore,understanding the deformation mechanism of materials undergoing TMF is important for extending the service life of aviation turbine blades.Here,third-generation and fourth-generation single crystal superalloys that experienced TMF deformation are investigated by SEM and TEM,including aberration-corrected STEM.The results show the formation of deformation twins on different {111} planes of the single crystal superalloys.In addition,a large number of recrystallized grains are found in parallel twin lamellae or around the intersection of twin lamellae.The grain boundary of recrystallized grains is primarily composed of twin boundaries,low-angle grain boundaries,and large-angle grain boundaries generated by twin intersections.Furthermore,the twinning boundaries after deformation are analyzed using aberration-corrected TEM.Consequently,the process of twinning-induced dynamic recrystallization is comprehensively understood,which improved the TMF fracture mechanism of single crystal high-temperature alloys.These results improve the understanding of the deformation mechanism of single crystal superalloys under service conditions.

关 键 词：镍基单晶高温合金 热机械疲劳 像差校正透射电镜 孪晶 再结晶 

分 类 号：TG111.8[金属学及工艺—物理冶金]