期刊
ACTA MATERIALIA
卷 76, 期 -, 页码 294-305出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2014.05.033
关键词
Nickel-based single-crystal superalloys; Rhenium effect; Electron microscopy; Creep; Interfacial dislocation networks
资金
- National 973 Project of China [2009CB623701]
- Chinese National Nature Science Foundation [11374174, 50971075, 51390471]
The synergistic action of local elemental distribution, and in particular Re doping, with interfacial dislocations at the gamma/gamma' interface is still one of the most considered and unclear issues during creep of nickel-based single-crystal superalloys. In order to investigate this problem, a detailed characterization of interfacial dislocations in a DD6 superalloy after creep loading for 12 h at high temperature and low stress was carried out using transmission electron microscopy and high-angle annular dark field scanning transmission electron microscopy techniques. In addition, the local elemental distribution near dislocation core regions was determined by energy dispersive X-ray spectroscopy (EDS) mapping. It was found for the first time that three types of interfacial protrusions are formed at the gamma/gamma' interface after creep loading for 12 h under conditions of high temperature and low stress and demonstrated that the formation of these features originates from dislocation motion. Additionally, EDS mapping provides evidence for co-segregation of Re with Cr and Co at the tip of the protrusions. Based on this, a model concerning dislocation core structure and dislocation climb was proposed to explain the different morphology of the protrusions. The observations highlight the importance of the coupling between Re segregation and gamma/gamma' interfacial dislocations for improving creep properties in nickel-based superalloys. The results of the study will be beneficial for the design of new high-temperature materials and for understanding the origin of the effect of Re additions in nickel-based single-crystal superalloys. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据