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Andrej Atrens - One of the best experts on this subject based on the ideXlab platform.
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Stress Corrosion cracking of EV31A in 0.1 M Na2SO4 saturated with Mg(OH)2
'Elsevier BV', 2018Co-Authors: Yushan Zhou, Zhiming Shi, Jeffrey Venezuela, Akif Soltan, Andrej AtrensAbstract:This paper studied the Stress Corrosion cracking (SCC) of EV31A in 0.1 M Na2SO4 saturated with Mg(OH)2 using linearly increasing Stress tests, compared with pure Mg and WE43B. All three materials were susceptible to SCC. SCC susceptibility increased with decreasing applied Stress rate. The threshold Stress was 0.3 × (yield Stress) for pure Mg, 0.6 × (yield Stress) for EV31A, and 0.8 ×(yield Stress) for WE43B. The SCC velocities at an applied Stress rate of 7.3 × 10 − 4 MPa s−1 were 7.2 × 10 − 8 m s−1 for pure Mg, 5.6 × 10 − 9 m s−1 for WE43B, and 1.5 × 10 − 9 m s−1 for EV31A. Keywords: SCC (Stress Corrosion cracking), Magnesium alloys, LIST (linearly increasing Stress test
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Stress Corrosion cracking of high strength steels
Corrosion Reviews, 2013Co-Authors: Sridhar Ramamurthy, Andrej AtrensAbstract:The mechanisms of Stress Corrosion cracking (SCC) and hydrogen embrittlement were recently reviewed by Lynch in this journal. The present review, in contrast, focuses on the rate-limiting step of the SCC of low-alloy high-strength steels in water and particularly focuses on the influence of the applied Stress rate on the SCC of lowalloy high-strength steels. Linearly increasing Stress tests of low-alloy high-strength steels in distilled water indicated that the Stress Corrosion crack velocity increased with increasing applied Stress rate until the maximum crack velocity, corresponding to v in fracture mechanics tests in distilled water. Moreover, the crack velocity was dependent only on the applied Stress rate and was not influenced by the steel composition. The rate-limiting step could be the rupture of a surface film, which would control the rate of metal dissolution and/or the production and transport of hydrogen to the crack tip or to the regions ahead of the crack tip.
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metallurgical aspects of rock bolt Stress Corrosion cracking
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: Ernesto Villalba, Andrej AtrensAbstract:Abstract This paper reports on the metallurgical influence on rock bolt Stress Corrosion cracking for a range of: (1) existing rock bolt steels and (2) commercial steels. Rock bolt steels 1355, MAC and MA840B displayed SCC when loaded at 0.019 MPa s −1 in the sulphate pH 2.1 solutions at the free Corrosion potential. They had comparable threshold Stresses and comparable Stress Corrosion crack velocities. Rock bolts steel 5152CW10D had the best SCC resistance of the rock bolt steels tested. Cold work increased the resistance of 5152 to SCC. The five commercial steels 1008, X65, X70, 4140 and 4145H were subjected to the linearly increasing Stress test (LIST) in the dilute pH 2.1 sulphate solution at their free Corrosion potential and at increasingly negative applied potential values to −1500 mV. The increasingly negative applied potential increases the aggressivity of SCC conditions because of increasing hydrogen liberated at the specimen surface. The steels 1008, X65, X70 and 4145H resisted SCC for all applied potentials including −1500 mV.
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Review of Stress Corrosion cracking of pipeline steels in "low" and "high" pH solutions
Journal of Materials Science, 2003Co-Authors: Bingyan Fang, Andrej Atrens, En-hou Han, Jinxiu Wang, Z. Y. ZhuAbstract:This paper reviews the current understanding of the mechanisms of Stress Corrosion cracking of pipeline steels. The similarities, the differences and the influencing factors are considered for the “high pH” Stress Corrosion cracking caused by a concentrated bicarbonate-carbonate solution, and for the “low pH” Stress Corrosion cracking due to a diluter solution. For high pH Stress Corrosion cracking, it is well accepted that the mechanism involves anodic dissolution for crack initiation and propagation. In contrast, it has been suggested that the low pH Stress Corrosion cracking is associated with the dissolution of the crack tip and sides, accompanied by the ingress of hydrogen into the pipeline steel. But the precise influence of hydrogen on the mechanism needs to be further studied.
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initiation of Stress Corrosion cracking for pipeline steels in a carbonate bicarbonate solution
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 1996Co-Authors: Zf F Wang, Andrej AtrensAbstract:The linearly increasing Stress test (LIST) was used to study the Stress Corrosion cracking (SCC) behavior of a range of pipeline steels in carbonate-bicarbonate solution under Stress rate control at different applied potentials. Stress Corrosion cracking, at potentials below -800 mV(SCE), was attributed to hydrogen embrittlement. Stress Corrosion cracking, in the potential range from about-700 to -500 mV(SCE), was attributed to an anodic dissolution mechanism. In the anodic potential region, the SCC initiation Stress was larger than the yield Stress and was associated with significant plastic deformation at the cracking site. The relative SCC initiation resistance decreased with in-creasing yield strength. In the cathodic potential region, the SCC initiation Stress was smaller than the yield Stress of steel; it was approximately equal to the Stress at 0.1 pct strain(@#@ Σ0.1pct) for all the steels. The original surface was more susceptible to SCC initiation than the polished surface.
Gary S. Was - One of the best experts on this subject based on the ideXlab platform.
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Accelerated Stress Corrosion Crack Initiation of Alloys 600 and 690 in Hydrogenated Supercritical Water
Metallurgical and Materials Transactions A, 2017Co-Authors: Tyler Moss, Gary S. WasAbstract:The objective of this study is to determine whether Stress Corrosion crack initiation of Alloys 600 and 690 occurs by the same mechanism in subcritical and supercritical water. Tensile bars of Alloys 690 and 600 were strained in constant extension rate tensile experiments in hydrogenated subcritical and supercritical water from 593 K to 723 K (320 °C to 450 °C), and the crack initiation behavior was characterized by high-resolution electron microscopy. Intergranular cracking was observed across the entire temperature range, and the morphology, structure, composition, and temperature dependence of initiated cracks in Alloy 690 were consistent between hydrogenated subcritical and supercritical water. Crack initiation of Alloy 600 followed an Arrhenius relationship and did not exhibit a discontinuity or change in slope after crossing the critical temperature. The measured activation energy was 121 ± 13 kJ/mol. Stress Corrosion crack initiation in Alloy 690 was fit with a single activation energy of 92 ± 12 kJ/mol across the entire temperature range. Cracks were observed to propagate along grain boundaries adjacent to chromium-depleted metal, with Cr_2O_3 observed ahead of crack tips. All measures of the SCC behavior indicate that the mechanism for Stress Corrosion crack initiation of Alloy 600 and Alloy 690 is consistent between hydrogenated subcritical and supercritical water.
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Stress Corrosion cracking of ferritic martensitic steels in simulated boiling water reactor environment
Corrosion, 2015Co-Authors: Parag M Ahmedabadi, Gary S. WasAbstract:Stress Corrosion cracking of advanced powder metallurgy technology (APMT) and T91 (UNS K90901, ferritic-martensitic) steels were investigated in the as-received and proton-irradiated conditions in simulated boiling water reactor environment (2 ppm O2) using constant extension tensile tests at 288°C at a strain rate of 3×10−7 s−1. Significant Stress Corrosion cracking was not observed in the as-received condition. A few cracks, perpendicular the loading direction, were observed in the proton-irradiated (5 dpa) specimen of T91. No intergranular fracture was observed on the fracture surfaces of as-received and proton-irradiated specimens of T91. No cracking was observed for APMT in un-irradiated and proton-irradiated (5 dpa) conditions. Results indicate that both APMT and T91 are highly resistant to Stress Corrosion cracking in a reactor environment and that irradiation to 5 dpa does not appreciably increase susceptibility.
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irradiation assisted Stress Corrosion cracking
Corrosion Reviews, 2011Co-Authors: Gary S. Was, Yugo Ashida, Peter L. AndresenAbstract:Irradiation-assisted Stress Corrosion cracking (IASCC) is aptly named since the effect of irradiation is to enhance an inherent susceptibility to Stress Corrosion cracking (SCC). This chapter introduces the basic SCC dependencies in austenitic stainless steels and nickel alloys under unirradiated conditions and then describes how they are accentuated or diminished as a result of radiation. SCC results from a confluence of Stress, microstructure, and water chemistry, and each is affected by irradiation. With increasing plant operation and improved laboratory capability, it has been concluded that true immunity to SCC growth apparently does not exist in common engineering materials although different conditions can produce large changes in SCC susceptibility. As nuclear power plants operate longer, an increased incidence of SCC can be expected unless active mitigation steps are taken.
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Corrosion and Stress Corrosion cracking in supercritical water
Journal of Nuclear Materials, 2007Co-Authors: Gary S. Was, Pantip Ampornrat, Gaurav Gupta, S Teysseyre, E A West, T R Allen, Kumar Sridharan, Lizhen Tan, Yun Chen, X RenAbstract:Abstract Supercritical water (SCW) has attracted increasing attention since SCW boiler power plants were implemented to increase the efficiency of fossil-based power plants. The SCW reactor (SCWR) design has been selected as one of the Generation IV reactor concepts because of its higher thermal efficiency and plant simplification as compared to current light water reactors (LWRs). Reactor operating conditions call for a core coolant temperature between 280 °C and 620 °C at a pressure of 25 MPa and maximum expected neutron damage levels to any replaceable or permanent core component of 15 dpa (thermal reactor design) and 100 dpa (fast reactor design). Irradiation-induced changes in microstructure (swelling, radiation-induced segregation (RIS), hardening, phase stability) and mechanical properties (strength, thermal and irradiation-induced creep, fatigue) are also major concerns. Throughout the core, Corrosion, Stress Corrosion cracking, and the effect of irradiation on these degradation modes are critical issues. This paper reviews the current understanding of the response of candidate materials for SCWR systems, focusing on the Corrosion and Stress Corrosion cracking response, and highlights the design trade-offs associated with certain alloy systems. Ferritic–martensitic steels generally have the best resistance to Stress Corrosion cracking, but suffer from the worst oxidation. Austenitic stainless steels and Ni-base alloys have better oxidation resistance but are more susceptible to Stress Corrosion cracking. The promise of grain boundary engineering and surface modification in addressing Corrosion and Stress Corrosion cracking performance is discussed.
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Stress Corrosion cracking behavior of alloys in aggressive nuclear reactor core environments
Corrosion, 2007Co-Authors: Gary S. Was, Peter L. AndresenAbstract:Abstract The effects of irradiation on Stress Corrosion cracking occur through changes in the water chemistry and in the alloy microstructure. Considerable reactor experience has shown that a high-temperature water environment and a radiation field combine to produce irradiation-assisted Stress Corrosion cracking (IASCC) in core components of light water reactors. The principal effect of irradiation on water chemistry is through radiolysis, which results in an increase in the Corrosion potential through the formation of radiolytic species consisting of radicals and molecules that can be oxidizing or reducing. In addition, profound effects of irradiation on the microchemistry and alloy microstructure create numerous pathways for IGSCC to occur. Radiation-induced segregation, the formation of a dislocation loop microstructure, irradiation hardening, and irradiation creep all occur simultaneously in space and time. Unfolding these various effects to determine the primary factors governing the observed effect...
M Kumosa - One of the best experts on this subject based on the ideXlab platform.
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resistance to Stress Corrosion cracking of unidirectional ecr glass polymer composites for high voltage composite insulator applications
Composites Part A-applied Science and Manufacturing, 2003Co-Authors: L Kumosa, M Kumosa, D ArmentroutAbstract:Stress Corrosion experiments were performed on unidirectional ECR-glass/polymer composites with the modified polyester, epoxy and vinyl ester resins for the use in high voltage composite insulator applications. Two types of ECR-glass fibers were investigated with low and high counts of gaseous inclusions (seeds) within the glass. The Stress Corrosion tests were performed in nitric acid under four point bending conditions and the resistance to Stress Corrosion cracking (SCC) of the composites was determined for as-supplied and sandblasted surface conditions. In addition, the materials were analyzed for their micro-hardness and surface fiber exposure. The resistance to SCC of the ECR-glass/polymer composites was compared with that of the E-glass/polymer systems. It has been found that the ECR-glass fiber composites vastly out-perform their E-glass counterparts regarding their resistance to SCC in nitric acid. The Stress Corrosion data presented in this work should help composite insulator manufacturers in the selection of composite rod materials with substantially increased resistance to SCC to lower the number of brittle fracture failures among their products.
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an evaluation of the critical conditions for the initiation of Stress Corrosion cracking in unidirectional e glass polymer composites
Composites Science and Technology, 2001Co-Authors: L Kumosa, D Armentrou, M KumosaAbstract:The purpose of this work is to establish the critical surface conditions leading to the initiation of Stress-Corrosion cracks on the as-supplied surfaces of three unidirectional E-glass/polymer composites with modified polyester, epoxy and vinyl ester resins subjected to a nitric acid solution without mechanical loads. The composite materials considered in this study are commonly used in composite high-voltage insulators on overhead transmission lines with the line voltages ranging from 69 to 735 kV. The initiation of Stress-Corrosion cracks in exposed glass fibers on the composite surfaces was observed in the absence of externally applied mechanical loads. However, the crack initiation rates are strongly dependent on the amount of exposed fibers. After the initial stage of crack initiation, no further Stress-Corrosion damage is observed in the composites. The E-glass/vinyl ester system appears to be more resistant to the initiation of Stress-Corrosion cracking in comparison with the other two composite systems investigated. This system exhibits the lowest number of Stress-Corrosion cracks and the lowest total surface area of exposed fibers on the composite surfaces. The E-glass/epoxy composite shows the lowest resistance to Stress Corrosion with the largest areas of exposed fibers. The effect of exposed fibers on the Stress-Corrosion process in unidirectional E-glass/polymer composites used in high voltage insulators has not been previously reported. It is clear that in order to reduce the rates of failure of composite high-voltage insulators by Stress-Corrosion cracking (brittle fracture), the presence of exposed fibers on their rod surfaces should be minimized.
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initiation of Stress Corrosion cracking in unidirectional glass polymer composite materials
Composites Science and Technology, 2001Co-Authors: M Megel, L Kumosa, T Ely, D Armentrout, M KumosaAbstract:The purpose of this research is to determine the resistance to Stress-Corrosion cracking (SCC) of three unidirectional (pultruded) E-glass/polymer composites based on modified polyester, epoxy and vinyl ester resins. The composites have been subjected to a nitric acid solution of pH 1.2 in a newly designed four-point bend fixture. The Stress-Corrosion process was initiated on the as-supplied surfaces of the composites. The process has been monitored for acoustic emissions and the Stress-Corrosion surface damage in the specimens was investigated by the use of scanning electron microscopy. Experimental results indicate that the Stress-Corrosion cracks originate predominantly from exposed glass fibers on the surfaces of the composites. The process can be successfully monitored by means of acoustic emission equipment. Three stages of SCC, crack initiation, sub-critical crack extension and stable crack propagation, can be distinguished by carefully examining the curves of acoustic emission (number of events) versus time. For the first and second stages of SCC, the acoustic emission outputs are linear functions of time. The slopes of the first and second stages of the curves of acoustic emission versus time have been used to determine quantitatively both the resistance of the composites to crack initiation and sub-critical crack extension, respectively. It has been shown in this research that the resistance to the initiation of SCC in nitric acid of the E-glass/vinyl ester composite is approximately 10 times greater than the E-glass/epoxy composite. Furthermore, the E-glass/epoxy system exhibits approximately 5 times higher resistance to the initiation of SCC than the E-glass/modified polyester system. The sub-critical crack extension process is also significantly more rapid in the E-glass/modified polyester than in the E-glass/epoxy composite.
L Kumosa - One of the best experts on this subject based on the ideXlab platform.
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resistance to Stress Corrosion cracking of unidirectional ecr glass polymer composites for high voltage composite insulator applications
Composites Part A-applied Science and Manufacturing, 2003Co-Authors: L Kumosa, M Kumosa, D ArmentroutAbstract:Stress Corrosion experiments were performed on unidirectional ECR-glass/polymer composites with the modified polyester, epoxy and vinyl ester resins for the use in high voltage composite insulator applications. Two types of ECR-glass fibers were investigated with low and high counts of gaseous inclusions (seeds) within the glass. The Stress Corrosion tests were performed in nitric acid under four point bending conditions and the resistance to Stress Corrosion cracking (SCC) of the composites was determined for as-supplied and sandblasted surface conditions. In addition, the materials were analyzed for their micro-hardness and surface fiber exposure. The resistance to SCC of the ECR-glass/polymer composites was compared with that of the E-glass/polymer systems. It has been found that the ECR-glass fiber composites vastly out-perform their E-glass counterparts regarding their resistance to SCC in nitric acid. The Stress Corrosion data presented in this work should help composite insulator manufacturers in the selection of composite rod materials with substantially increased resistance to SCC to lower the number of brittle fracture failures among their products.
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an evaluation of the critical conditions for the initiation of Stress Corrosion cracking in unidirectional e glass polymer composites
Composites Science and Technology, 2001Co-Authors: L Kumosa, D Armentrou, M KumosaAbstract:The purpose of this work is to establish the critical surface conditions leading to the initiation of Stress-Corrosion cracks on the as-supplied surfaces of three unidirectional E-glass/polymer composites with modified polyester, epoxy and vinyl ester resins subjected to a nitric acid solution without mechanical loads. The composite materials considered in this study are commonly used in composite high-voltage insulators on overhead transmission lines with the line voltages ranging from 69 to 735 kV. The initiation of Stress-Corrosion cracks in exposed glass fibers on the composite surfaces was observed in the absence of externally applied mechanical loads. However, the crack initiation rates are strongly dependent on the amount of exposed fibers. After the initial stage of crack initiation, no further Stress-Corrosion damage is observed in the composites. The E-glass/vinyl ester system appears to be more resistant to the initiation of Stress-Corrosion cracking in comparison with the other two composite systems investigated. This system exhibits the lowest number of Stress-Corrosion cracks and the lowest total surface area of exposed fibers on the composite surfaces. The E-glass/epoxy composite shows the lowest resistance to Stress Corrosion with the largest areas of exposed fibers. The effect of exposed fibers on the Stress-Corrosion process in unidirectional E-glass/polymer composites used in high voltage insulators has not been previously reported. It is clear that in order to reduce the rates of failure of composite high-voltage insulators by Stress-Corrosion cracking (brittle fracture), the presence of exposed fibers on their rod surfaces should be minimized.
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initiation of Stress Corrosion cracking in unidirectional glass polymer composite materials
Composites Science and Technology, 2001Co-Authors: M Megel, L Kumosa, T Ely, D Armentrout, M KumosaAbstract:The purpose of this research is to determine the resistance to Stress-Corrosion cracking (SCC) of three unidirectional (pultruded) E-glass/polymer composites based on modified polyester, epoxy and vinyl ester resins. The composites have been subjected to a nitric acid solution of pH 1.2 in a newly designed four-point bend fixture. The Stress-Corrosion process was initiated on the as-supplied surfaces of the composites. The process has been monitored for acoustic emissions and the Stress-Corrosion surface damage in the specimens was investigated by the use of scanning electron microscopy. Experimental results indicate that the Stress-Corrosion cracks originate predominantly from exposed glass fibers on the surfaces of the composites. The process can be successfully monitored by means of acoustic emission equipment. Three stages of SCC, crack initiation, sub-critical crack extension and stable crack propagation, can be distinguished by carefully examining the curves of acoustic emission (number of events) versus time. For the first and second stages of SCC, the acoustic emission outputs are linear functions of time. The slopes of the first and second stages of the curves of acoustic emission versus time have been used to determine quantitatively both the resistance of the composites to crack initiation and sub-critical crack extension, respectively. It has been shown in this research that the resistance to the initiation of SCC in nitric acid of the E-glass/vinyl ester composite is approximately 10 times greater than the E-glass/epoxy composite. Furthermore, the E-glass/epoxy system exhibits approximately 5 times higher resistance to the initiation of SCC than the E-glass/modified polyester system. The sub-critical crack extension process is also significantly more rapid in the E-glass/modified polyester than in the E-glass/epoxy composite.
En-hou Han - One of the best experts on this subject based on the ideXlab platform.
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Stress Corrosion cracking in the heat affected zone of a stainless steel 308L-316L weld joint in primary water
Corrosion Science, 2016Co-Authors: Lijin Dong, Qunjia Peng, Wei Ke, En-hou Han, Lei WangAbstract:Stress Corrosion cracking (SCC) in the heat affected zone (HAZ) of a stainless steel 308L-316L weld joint in primary water of pressurized water reactor was investigated. Stress Corrosion crack growth in the HAZ was observed in off-normal primary water chemistry with dissolved oxygen, but not in normal primary water chemistry with dissolved hydrogen. This suggests that it is unlikely a Stress Corrosion crack propagating in the HAZ could reach the fusion boundary and penetrate into the weld metal under normal primary water chemistry conditions. Microstructure analysis of the crack tip suggests that the SCC follows the slip-oxidation mechanism.
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Review of Stress Corrosion cracking of pipeline steels in "low" and "high" pH solutions
Journal of Materials Science, 2003Co-Authors: Bingyan Fang, Andrej Atrens, En-hou Han, Jinxiu Wang, Z. Y. ZhuAbstract:This paper reviews the current understanding of the mechanisms of Stress Corrosion cracking of pipeline steels. The similarities, the differences and the influencing factors are considered for the “high pH” Stress Corrosion cracking caused by a concentrated bicarbonate-carbonate solution, and for the “low pH” Stress Corrosion cracking due to a diluter solution. For high pH Stress Corrosion cracking, it is well accepted that the mechanism involves anodic dissolution for crack initiation and propagation. In contrast, it has been suggested that the low pH Stress Corrosion cracking is associated with the dissolution of the crack tip and sides, accompanied by the ingress of hydrogen into the pipeline steel. But the precise influence of hydrogen on the mechanism needs to be further studied.
