Effects of macro-scale corrosion damage feature on fatigue crack initiation and fatigue behavior

Co, Noelle Easter C.; Burns, James T.

doi:10.1016/j.ijfatigue.2017.05.028

Cited by 60 publications

(36 citation statements)

References 79 publications

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“…It was also observed that localized corrosion promoted initiation of multiple cracks, and the presence of the pits causing stress concentration greatly accelerated crack initiation and promoted crack growth. These experimental results are in agreement with the finding reported previously on the fatigue failure of pre‐corroded aluminum alloys 2024 and 7050 . Although the fact that prior localized corrosion causes the degradation of mechanical properties of aluminum alloy and promotes crack initiation although stress concentration is well known, there is still a lack of quantitative analysis of when and where these cracks initiate, and how they evolve and interact leading to final failure, especially for different levels of prior corrosion.…”

Section: Resultssupporting

confidence: 91%

“…Optical microscopy monitoring of pre‐corroded 7075‐T6 aluminum alloy specimen surfaces, to investigate short crack growth, revealed that short crack growth life under salt water conditions was approximately 5 to 8 times lower than in ambient air . A crack surface marker‐band method was used to determine the short crack growth rate of AA7050‐T7451 samples with macro scale corrosion damage; crack growth rates were shown to converge to comparable values for varied corrosion morphologies …”

Section: Introductionmentioning

confidence: 99%

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Effect of pre‐corrosion on damage evolution and crack propagation in aluminum alloy 7050‐T7651

Song

Bai

Zhang

et al. 2018

Fatigue Fract Eng Mat Struct

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This paper investigates the effects of pre‐corrosion on the tensile behavior of aluminum alloy 7050‐T7651. A combined experimental approach involving digital image correlation, scanning electron microscopy, and tensile testing is presented for quantitative and qualitative analysis. A tensile damage model is presented for plasticity‐induced, post‐corrosion mechanical damage for interpretation and identification of damage and cracking thresholds. Although multiple corrosion‐induced cracks evolve simultaneously in diffuse regions, propagation and coalescence of the main cracks, originating from key damage regions, dominate the failure process. A combined corrosion and mechanical damage model was used to successfully predict the effects of pre‐corrosion on the tensile stress‐strain response.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Effect of pre‐corrosion on damage evolution and crack propagation in aluminum alloy 7050‐T7651

Song

Bai

Zhang

et al. 2018

Fatigue Fract Eng Mat Struct

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“…However, it is useful to comment on the fatigue life results presented in Figure 4; there are 4 critical observations. 15,29,75,76 Third, in general, specimens tested in 0.6 M NaCl resulted in shorter fatigue lives than those tested in lab air. However, no clear trend was observed suggesting that this is the expected scatter in fatigue life, consistent with prior observations for fatigue behaviour in various stainless steels.…”

Section: Fatigue Testsmentioning

confidence: 95%

“…47,75,[78][79][80] The local stress/strain fields specific to the corrosion geometry and local microstructure can be used to calculate fatigue indicator parameters, which are micro-mechanical models that aim to capture the local grain-scale driving force for crack formation and small crack propagation. For example, in some instances, a relatively small pit (<90th percentile, with over 100 larger pits existing on the specimen) initiates the cracking.…”

Section: Interpretation and Identification Of The Macro-scale Corromentioning

confidence: 99%

The effect of pit size and density on the fatigue behaviour of a pre‐corroded martensitic stainless steel

McMurtrey

Mills

Burns

2018

Fatigue Fract Eng Mat Struct

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UNS S17400 steel is used in turbines for the aerospace and utility industries. While it is generally corrosion resistant, it is susceptible to pitting when exposed to aqueous chloride environments. Effects of pitting characteristics, such as depth, width, and local density on fatigue life, have been studied in this work to better inform criteria for component replacement or repair. While pit depth correlates well with cracking, the deepest pit never initiated the crack that ultimately led to failure. The clustering of pits, or local pitting density, also correlated well with crack initiation location; however, the densest region of pitting was not always the location where cracking occurred. There is likely no single metric that directly correlates pitting with fatigue cracking, rather there is a combination of pitting characteristics that ultimately lead to cracking. The results from this work suggest that pit depth and local pitting density are among the more important metrics.

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“…47 Image refinement and pit volume calculation was performed using MountainsMaps imaging topography software. [48][49][50] Calculations were made by multiplying the average pit volume by the total number of pits and normalizing for area. The results presented here indicate that the level of resistance (low frequency impedance (Z 0.01 )) afforded by the coating system (where, in this study, any deviation is wholly dependent on the pretreatment as the only variable between the uncoated systems) directly effects the global galvanic protection potential.…”

mentioning

confidence: 99%

Performance of a Magnesium-Rich Primer on Pretreated AA2024-T351 in Full Immersion: a Galvanic Throwing Power Investigation Using a Scanning Vibrating Electrode Technique

Kannan

Glover

McMurray

et al. 2018

J. Electrochem. Soc.

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The scanning vibrating electrode technique (SVET) was employed to examine the effect of 'galvanic throwing power' and the distance over which a Mg-rich primer (MgRP) provided sacrificial anode-based cathodic protection to AA2024-T351. Three systems were investigated in full immersion conditions where the same MgRP was used with three different pretreatments: Non-film forming (NFF), trivalent chromium pretreatment (TCP) and anodization with a chromate seal (ACS). Experiments were conducted with two coating/defect area ratios and three parameters were monitored: 1) the maximum peak height of local anodes, inferring the location and intensity of pits, 2) the current density profile at the coating/defect interface (CDI) region and 3) total integrated anodic and cathodic current density values of defined areas in the defect region moving progressively away from the CDI. The NFF-based system was shown to provide the superior galvanic throwing power and a quasi-steady-state galvanic current distribution was detected in the defect region adjacent to the CDI indicating enhanced cathodic activity in response to the MgRP. High resistance between the MgRP and the substrate, due to the thickness of the pretreatment layer, appeared to mediate galvanic interactions in the case of TCP and ACS-based systems.

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Effects of macro-scale corrosion damage feature on fatigue crack initiation and fatigue behavior

Cited by 60 publications

References 79 publications

Effect of pre‐corrosion on damage evolution and crack propagation in aluminum alloy 7050‐T7651

Effect of pre‐corrosion on damage evolution and crack propagation in aluminum alloy 7050‐T7651

The effect of pit size and density on the fatigue behaviour of a pre‐corroded martensitic stainless steel

Performance of a Magnesium-Rich Primer on Pretreated AA2024-T351 in Full Immersion: a Galvanic Throwing Power Investigation Using a Scanning Vibrating Electrode Technique

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