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Title: Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water

Abstract

Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 (UNS N06690) materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for either the 21% or 31%CW CLT specimens loaded at their yield stress after ~9,220 hours, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showed DCPD-indicated crack initiation after 10,400 hours of exposure at constant stress intensity, which was resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and discusses their effects on crack initiationmore » in CW alloy 690.« less

Authors:
 [1];  [1];  [1];  [1]
  1. Pacific Northwest National Laboratory, 622 Horn Rapids Road, P.O. Box 999, Richland, Washington 99352.
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1378041
Report Number(s):
PNNL-SA-125212
Journal ID: ISSN 0010-9312; 49618; 830403000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Corrosion; Journal Volume: 73; Journal Issue: 10
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; intergranular stress corrosion cracking; crack initiation; alloy 690; cold work; creep cavities; grain boundary microstructure; Environmental Molecular Sciences Laboratory

Citation Formats

Zhai, Ziqing, Toloczko, Mychailo, Kruska, Karen, and Bruemmer, Stephen. Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water. United States: N. p., 2017. Web. doi:10.5006/2470.
Zhai, Ziqing, Toloczko, Mychailo, Kruska, Karen, & Bruemmer, Stephen. Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water. United States. doi:10.5006/2470.
Zhai, Ziqing, Toloczko, Mychailo, Kruska, Karen, and Bruemmer, Stephen. Mon . "Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water". United States. doi:10.5006/2470.
@article{osti_1378041,
title = {Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water},
author = {Zhai, Ziqing and Toloczko, Mychailo and Kruska, Karen and Bruemmer, Stephen},
abstractNote = {Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 (UNS N06690) materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for either the 21% or 31%CW CLT specimens loaded at their yield stress after ~9,220 hours, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showed DCPD-indicated crack initiation after 10,400 hours of exposure at constant stress intensity, which was resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and discusses their effects on crack initiation in CW alloy 690.},
doi = {10.5006/2470},
journal = {Corrosion},
number = 10,
volume = 73,
place = {United States},
year = {Mon May 22 00:00:00 EDT 2017},
month = {Mon May 22 00:00:00 EDT 2017}
}