Stress Corrosion and Hydrogen Embrittlement in an Aluminum Alloy

Gest, R. J.; Troiano, A. R.

doi:10.5006/0010-9312-30.8.274

Cited by 174 publications

(55 citation statements)

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“…AA7xxx alloys are known to be susceptible to intergranular stress corrosion cracking (IGSCC) when subjected to a tensile stress in an aggressive environment [20,21,[31][32][33][34][35]. However, in this study the sharp IGC fissures grew in samples that were unstressed.…”

Section: Sharp Igc Fissure Mechanismmentioning

confidence: 79%

Kinetics of sharp intergranular corrosion fissures in AA7178

Huang

Frankel

2007

Corrosion Science

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During service in structural aircraft applications, AA7178 has been found to develop sharp intergranular corrosion (IGC) fissures, a special form of attack. A new laboratory approach to quantify the kinetics of sharp IGC fissure growth was developed in this work. Sharp IGC fissures, similar to those formed in service, grew in samples that were given an electrochemical pre-treatment and then exposed in a humid environment. The time for the first sharp IGC fissure to penetrate the thin sample was determined by visual observation of the back side of the sample. The depth of the sharp IGC fissure was determined by serial sectioning. The kinetics measured by this approach did not represent the fastest rates, but rather the rates of long sharp IGC fissures. Relative humidity had no measurable effect on fissure kinetics, indicating that there was little connection of the local sharp IGC fissure region with the outside environment. AA7178 in the as-received and T7 conditions exhibited slower sharp IGC fissure rates than in the T6 condition. The sharp IGC fissures were found to be filled with corrosion products, which possibly exert a stress that could play an important role in driving fissure growth. It is suggested that the sharp IGC fissure could be a form of SCC.

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Section: Sharp Igc Fissure Mechanismmentioning

confidence: 79%

Kinetics of sharp intergranular corrosion fissures in AA7178

Huang

Frankel

2007

Corrosion Science

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“…There have been several mechanisms proposed, capable of explaining the SCC behavior of aluminum alloys. Those mechanisms include, but not limited to, anodic dissolution [26][27][28][29][30][31] and hydrogen embrittlement [32][33][34][35][36][37] of grain boundary.…”

Section: Scc Mechanismmentioning

confidence: 99%

“…This is an example of grain boundary hydrogen embrittlement mechanism. [32][33][34][35][36][37] Therefore, the SCC mechanism for the two aluminum alloys must be simultaneous anodic dissolution and hydrogen embrittlement of grain boundaries under slow straining in an aqueous NaCl solution.…”

Section: Scc Mechanismmentioning

confidence: 99%

Stress Corrosion Cracking of Aluminum Alloys

Lee¹,

Taylor²,

Liu³

et al. 2012

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)Naval Air The effects of environment concentration and strain rate on the stress corrosion cracking (SCC) behavior of 5083-H131 and 7075-T6 aluminum alloys were studied, conducting electrochemical measurement and slow strain rate test. The employed environments were pH 7.3 aqueous solutions of 0 to 20% NaCl, and the applied strain rate ranged from 10 -8 s -1 to 10 -4 s -1 . A comparative test was also carried out in air. After the tests, the fracture surface morphology was examined by scanning electron microscopy, and the microstructure in the vicinity of the fracture by light microscopy to clarify the SCC mode. The results indicated: 1. The SCC susceptibility is a little below 0.5% NaCl but it is raised noticeably with increasing NaCl concentration above 0.5% NaCl. 2. Compared to 7075-T6 aluminum alloy, 5083-H131 aluminum alloy has inferior mechanical property and it is highly susceptible to SCC. 3. The corrosion potential is lower and the corrosion rate is greater for higher NaCl concentration. 4. The SCC susceptibility increases with decreasing strain rate. 4. The SCC mode is crack initiation at the junctions of grain boundaries with specimen surface, and crack propagation along grain boundaries into the specimen, attributed to hydrogen embrittlement and anodic dissolution. ii SUMMARY The effects of environment concentration and strain rate on the stress corrosion cracking (SCC) behavior of 5083-H131 and 7075-T6 aluminum alloys were studied, conducting electrochemical measurement and slow strain rate test. The employed environments were pH 7.3 aqueous solutions of 0 to 20% NaCl, and the applied strain rate ranged from 10 -8 s -1 to 10 -4 s -1 . A comparative test was also carried out in air. After the tests, the fracture surface morphology was examined by scanning electron microscopy, and the microstructure in the vicinity of the fracture by light microscopy to clarify the SCC mode. The results indicated: 1. The SCC susceptibility is a little below 0.5% NaCl but it is raised noticeably with increasing NaCl concentration above 0.5% NaCl. 2. Compared to 7075-T6 aluminum alloy, 5083-H131 aluminum alloy has inferior mechanical property and it is highly susceptible to SCC. 3. The corrosion potential is lower and the corrosion rate is greater for higher NaCl concentration. 4. The SCC susceptibility increases with decreasing strain rate. 4. The SCC mode is crack initiation at the junctions of grain boundaries with specimen surface, and crack propagation along grain boundaries into the specimen, attributed to hydrogen embrittlement and anodi...

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“…From early state of chemical engineering hydrogen embrittlement (HE) is a known problem [11,12] in metal industry, which had to be faced already in 1911 during the development of ammonia synthesis by Haber and Bosch. The first attempt to overcome problems due to cracking because of reaction of hydrogen with carbon in the steel at high pressures was performed by coating the inner wall of the reactor with pure iron and drilling narrow holes in the outer steel wall, so that hydrogen could diffuse through the iron and leaf the reactor without causing damage [13].…”

Section: Introductionmentioning

confidence: 99%

Challenges in hydrogen quantification using Kelvin probe technique at different levels of relative humidity

Burgstaller

Schimo

Hassel

2017

J Solid State Electrochem

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Kelvin probe-based contact potential measurements were conducted with in situ electrochemical hydrogen loading of a Pd membrane with a thickness of 100 μm. The theoretical basis of diffusion coefficient calculation based on measured response time of potential drop, arising from hydrogen arriving at the detection side of the Pd membrane, was discussed. In situ hydrogen loading was also utilized for insertion of different amounts of hydrogen into the Pd sample while monitoring the resulting contact potential difference changes. Measurement of contact potential difference at different final values of hydrogen concentration in the Pd membrane was performed at various atmospheric conditions, focusing in this work on increasing relative humidity (4 to 85% rH). Moreover, the effect of humidity changes on hydrogen effusion kinetics at room temperature and low oxygen content (<1%) was studied.

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Stress Corrosion and Hydrogen Embrittlement in an Aluminum Alloy

Cited by 174 publications

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Kinetics of sharp intergranular corrosion fissures in AA7178

Kinetics of sharp intergranular corrosion fissures in AA7178

Stress Corrosion Cracking of Aluminum Alloys

Challenges in hydrogen quantification using Kelvin probe technique at different levels of relative humidity

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