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Macrostructure and Micro chemistry Analysis on Stress Corrosion Cracking (SCC) of Alloy 690

Geda, Lemi Gemechu
http://rave.ohiolink.edu/etdc/view?acc_num=osu1374161228

Abstract Details

2013, Master of Science, Ohio State University, Mechanical Engineering.
Stress Corrosion Cracking (SCC) is a failure that results from the combination of tensile stress, corrosive environment, and material susceptibility. SCC is a serious metallurgical problem with an impact on current and future designs of structural components and nuclear reactors. The initiation of SCC is difficult to detect and control because of highly localized nature of chemical and mechanical conditions. SCC mechanism is dependent on the microstructure and grain boundaries for a given alloy composition. Alloy 690 is used in a pressurized water reactor (PWR) and steam engines due to its extreme resistance to common corrosion in high temperature and aggressive environment. Although alloy 690 has a great tendency to withstand corrosion and aggressive environment SCC has been associated with significant replacement of power and downtime in its application. Alloy 690 has been studied to understand, predict, and avoid costly and dangerous failures that could occur due to SCC. The main goal of the present study is to study the relationship between the structural nature, chemical properties and mechanical properties on and near grain boundaries in alloy 690 to identify their role in the resistance and susceptibility to SCC. The microstructure and microchemistry of alloy 690 at the SCC surface and crack fronts has been studied to improve the fundamental understanding of primary water stress corrosion cracking (PWSCC). The alloy 690 was chosen as the material of interest for this study because of its relevance in current application in nuclear industries and application on different structural component at extreme environmental conditions. An integrated approach to study the structural, mechanical and chemical information at nano-scale in selected grain boundaries was developed. Microstructural and micro chemical examinations were conducted using field emission scanning electron microscope (FESEM). High resolution SEM observation were obtained by backscatter electron (BSE) imaging and in-lens FESEM which provide topographical information with virtually unlimited depth of field and less distorted images with special resolution. Also line profiling and mapping were performed using energy dispersive X-ray spectroscopy (EDS) to define the local features and chemical composition.
Jinsuo Zhang, Dr (Advisor)
Prasad Mokashi, Dr (Advisor)
79 p.
Mechanical Engineering
Stress Corrosion Cracking

Recommended Citations

Citations

  • Geda, L. G. (2013). Macrostructure and Micro chemistry Analysis on Stress Corrosion Cracking (SCC) of Alloy 690 [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1374161228

    APA Style (7th edition)

  • Geda, Lemi. Macrostructure and Micro chemistry Analysis on Stress Corrosion Cracking (SCC) of Alloy 690 . 2013. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1374161228.

    MLA Style (8th edition)

  • Geda, Lemi. "Macrostructure and Micro chemistry Analysis on Stress Corrosion Cracking (SCC) of Alloy 690 ." Master's thesis, Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1374161228

    Chicago Manual of Style (17th edition)

osu1374161228
923
© 2013, some rights reserved.Creative Commons License Macrostructure and Micro chemistry Analysis on Stress Corrosion Cracking (SCC) of Alloy 690 by Lemi Gemechu Geda is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.