3D time-resolved observations of corrosion and corrosion-fatigue crack initiation and growth in peak-aged Al 7075 using synchrotron X-ray tomography

Stannard, Tyler; Williams, Jason; Singh, Sudhanshu S.; Singaravelu, Arun Sundar S.; Xiao, Xianghui; Chawla, Nikhilesh

doi:10.1016/j.corsci.2018.04.029

Cited by 49 publications

(20 citation statements)

References 79 publications

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“…Both laboratory-based and synchrotron XCT have been used to study pit growth under immersed and atmospheric conditions, for galvanic couples and the evolution of environmentally-assisted cracking 2,[4][5][6][7][8][9][10][11][12][13][14][15] . Several recent studies utilized X-ray microtomography to directly measure the rate and morphology of intergranular corrosion of AA7075 and AA2024 during the initial stages of atmospheric corrosion under millimeter-sized chloride salt droplets 3,16,17 .…”

Section: Introductionmentioning

confidence: 99%

Revealing the growth kinetics of atmospheric corrosion pitting in aluminum via in situ microtomography

Noell

Schindelholz

2020

npj Mater Degrad

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Understanding the mechanistic relationship between the environment, microstructure, and local kinetics of atmospheric corrosion damage remains a central challenge. To address this challenge, this study used laboratory-based X-ray tomography to directly observe attack in-operando over an extended period, enabling insights into the evolving growth kinetics and morphology of individual pits over months of exposure. Damage progression associated with nine pits in a 99.9% pure aluminum wire exposed to chloride salts in humid air was characterized. Most pits grew at a nominally linear rate up until pit death, which occurred within 12–24 h of nucleation. Exceptions to this were observed, with three pits exhibiting bimodal growth kinetics and growing for 40 or more hours. This was explained by secondary droplets that formed near the pits, increasing the cathode area. A corrosion-driven drying mechanism likely contributed to pit death in both cases. Pits first grew into the material followed by lateral expansion.

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Section: Introductionmentioning

confidence: 99%

Revealing the growth kinetics of atmospheric corrosion pitting in aluminum via in situ microtomography

Noell

Schindelholz

2020

npj Mater Degrad

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“…What's more, there also exists several deep secondary cracks. It has been testified that the corrosion products and secondary cracks have close relation with the crack propagation behavior [37][38]. Therefore, the phenomena in crack propagation is remarkable and the overall improvement effect of Zn exceeds that of Cr coating.…”

Section: Mechanism Of Zn and Cr Coating On Corrosion Fatiguementioning

confidence: 99%

Durability method on corrosion fatigue performance of AH 32 steel

Huang

Wang

2019

Frattura Ed Integrità Strutturale

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A durability method in view of cathodic protection is proposed to improve the corrosion fatigue resistance of AH 32 steel in seawater. By aid of corrosion fatigue tests, the effects of thermal spraying Zn (zinc) and Cr (chromium) coating corrosion fatigue lives are quantitatively determined, respectively, and electrochemical measurement and fracture analysis are used to analyze the life-prolonging mechanism of these two coatings on corrosion fatigue. The results show that both Zn and Cr coating improve the corrosion fatigue resistance of AH 32 steel, and the effect enhances with the decrease of stress. The effect of Cr coating on corrosion fatigue of AH 32 steel mainly reflects in extending the crack initiation life for its better corrosion resistance. While the effect of Zn coating on corrosion fatigue lies in not only inhibiting the initiation of corrosion fatigue but also restraining crack propagation as cathodic protection materials. To sum up, Cr coating has a better durability effect than Zn coating at higher stress level, while Zn exceeds Cr at low stress level.

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“…There are a number of works concerning the development of fatigue cracks in various aluminium alloys subjected to corrosion [ 14 , 15 , 16 ], but they usually concern one particular type of environment with strictly defined physicochemical parameters, and the analysed parameter is only the crack development rate, without direct reference to fatigue life. There is also a large number of works describing experimental fatigue strength, but mainly in tension or compression conditions [ 17 , 18 , 19 , 20 , 21 ]. Relatively few of them concern bending or multiaxial conditions, and these are mainly in specialised applications.…”

Section: Introductionmentioning

confidence: 99%

Incorporation of Corrosion Effects into the Life-Cycle Analysis of AW-2017A-T4 Aluminium Alloy under Bending Moment

2020

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The paper presents the results of fatigue tests of corroded AW-2017A-T4 aluminium alloy samples subjected to an alternating (symmetrical) bending load. Although there are a number of works describing pre-corrosion fatigue in aluminium alloys, relatively few of them concern bending fatigue effects, in some selected alloys only. Here, the AW-2017A-T4 samples were exposed to electrochemical preliminary corrosion by immersion in an electrolyte, a 3.5% solution of NaCl in water. Several variants of series of samples differing in immersion time were tested. Based on the analysis of the results obtained, Basquin’s fatigue characteristics were developed and compared to the characteristics of the material in its nominal state, which allowed for conclusions on the influence of corrosion effects. The characteristic curves show the susceptibility of the test material to corrosive processes, which results in a decrease in fatigue life along with the increase of pre-corrosion time. The samples with longer immersion duration revealed larger surface losses and widespread corrosion pits.

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3D time-resolved observations of corrosion and corrosion-fatigue crack initiation and growth in peak-aged Al 7075 using synchrotron X-ray tomography

Cited by 49 publications

References 79 publications

Revealing the growth kinetics of atmospheric corrosion pitting in aluminum via in situ microtomography

Revealing the growth kinetics of atmospheric corrosion pitting in aluminum via in situ microtomography

Durability method on corrosion fatigue performance of AH 32 steel

Incorporation of Corrosion Effects into the Life-Cycle Analysis of AW-2017A-T4 Aluminium Alloy under Bending Moment

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