期刊
ENGINEERING FAILURE ANALYSIS
卷 46, 期 -, 页码 76-91出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.engfailanal.2014.08.007
关键词
Turbine blades; Ni-base superalloys; Microstructure; Creep; Fatigue
资金
- King Abdulaziz City for Science and Technology (KACST) through the Science & Technology Unit at King Fahd University of Petroleum & Minerals (KFUPM) [12-ADV2398-04]
First-stage turbine blades made of different grades of Ni-base superalloys and environmentally protected by the same Cr-modified aluminide coating are examined after exposure to the same service conditions in an electric power plant. Emphasis is placed upon microstructural changes, which can degrade the blade performance. Various electron-optical techniques are used to characterize the microstructures of unused and used blades. Three types of microstructural changes, which can lead to intergranular creep failure, are identified. These changes include: (i) coarsening, agglomeration, and rafting of the strengthening gamma'-phase, (ii) formation of gamma'-denuded zones alongside grain boundaries, and (iii) precipitation of intermetallic compounds. However, fatigue failure is also observed particularly in cases where higher than normal temperature is encountered. Although the same microstructural changes are found to occur in the blades included in the study, the respective kinetics appear to be influenced by at least two parameters: (i) exact superalloy composition and (ii) actual operating temperature. It is concluded that the life expectancy of blades used in such applications can be realized by appropriate selection of superalloy composition and adherence to design specifications. (C) 2014 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