Abstract
This study was aimed at investigating the intergranular attack near a stress corrosion crack (SCC) of alloy 690 in simulated pressurized water reactor (PWR) primary water environment. Solution annealed alloy 690 was evaluated for its SCC initiation susceptibility in 360, °C hydrogenated pure water using slow strain rate tensile technique. After the test, a grain boundary showing SCC initiation was sampled with Focused Ion Beam (FIB) milling. The microstructure and elemental distribution near the crack tip were studied using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The results show that intergranular oxidation occurs ahead of the crack tip and is preceded by diffusion induced grain boundary migration. The oxides at the crack tip are mainly composed of NiO and Cr2O3 which maintain rigid orientations with the neighboring grains. The adjacent migration zone is free of oxidization as a compact layer of Cr2O3 dominates at the oxide/substrate interfaces and the very tip region.
Original language | English |
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Title of host publication | Proceedings of the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems – Water Reactors |
Editors | Denise Paraventi, Michael Wright, John H. Jackson |
Publisher | Springer International Publishing |
Pages | 535-545 |
Number of pages | 11 |
ISBN (Print) | 9783319672434 |
DOIs | |
State | Published - 2018 |
Event | 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, 2017 - Portland, United States Duration: Aug 13 2017 → Aug 17 2017 |
Publication series
Name | Minerals, Metals and Materials Series |
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Volume | Part F9 |
ISSN (Print) | 2367-1181 |
ISSN (Electronic) | 2367-1696 |
Conference
Conference | 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, 2017 |
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Country/Territory | United States |
City | Portland |
Period | 08/13/17 → 08/17/17 |
Funding
Notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). The authors gratefully acknowledge financial support through the DOE I-NERI program contract 2011-01-K. The authors would like to thank Young Suk Kim and Sung Soo Kim from Korea Atomic Energy Research Institute for providing the materials for this study, and Alex Flick from the University of Michigan for his assistance with preparation of the high temperature autoclave systems. This research was performed, in part, using instrumentation provided by the Department of Energy, Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities.
Keywords
- Alloy 690
- Boundary migration
- Intergranular oxidation
- PWR
- SCC