摘要
γ′相是镍基单晶高温合金中主要强化相,研究γ′相的热稳定性对于优化合金的高温服役性能具有重要指导作用。本文采用扫描电镜和透射电镜,研究了长期时效过程中镍基单晶高温合金中γ′相的粗化行为。研究发现在长期时效过程中γ′相的尺寸逐渐增加,γ′相的尺寸由初始的方块状演变为长条状。结合定量化分析,发现γ′相尺寸的粗化速率逐渐降低、γ′相体积分数先降后增。γ′相尺寸在时效初始阶段遵循Ostwald熟化规律,粗化到一定程度会发生γ′相合并,合并后便不再按Ostwald熟化规律增加。γ′相尺寸体积分数变化规律是由外界温度升高及时间延长所引起的先回溶后脱溶所导致。
Theγ′phase is the main strengthening phase in Ni⁃base single crystal superalloy.The study of the thermal stability ofγ′phase plays an essential ro1e in optimizing the service properties of alloy at high temperatures.This paper studied the coarsening behavior ofγ′phase in Ni⁃base single crystal superalloy during long⁃term aging by scanning electron and transmission electron microscopes.It is found that the size ofγ′phase increases with time,and the morphology ofγ′phase evolves from cubic to long strip shape during long⁃term aging.Combined with quantitative analysis,it is found that the coarsening rate ofγ′phase size decreases gradually,and the volume fraction ofγ′phase decreases at first and then increases.In the initial stage of aging,the size ofγ′phase follows the law of Ostwald aging.It will merge when coarsening to a certain extent,and it will no longer increase according to the law of Ostwald aging after the merge.The variation of the volume fraction ofγ′phase is caused by the increase of external temperature and the prolongation of time,which produces the first dissolution and then the re⁃dissolution process.
作者
周慧
龙海波
毛圣成
张泽
韩晓东
ZHOU Hui;LONG Hai-bo;MAO Sheng-cheng;ZHANG Ze;HAN Xiao-dong(Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124;School of Materials Science and Engineering,Zhejiang University,Hangzhou Zhejiang 310027,China)
出处
《电子显微学报》
CAS
CSCD
北大核心
2022年第5期491-498,共8页
Journal of Chinese Electron Microscopy Society
基金
国家自然科学基金资助项目(Nos.91860202,52171001,52071003)
国家重点研发计划(No.2021YFA1200201)
北京新星计划资助(No.Z2111000021211701).
关键词
镍基单晶高温合金
γ′相热稳定性
长期时效
显微结构
Ni⁃based single crystal superalloys
thermal stability ofγ′phase
long⁃term aging
microstructure
