Simplified Exfoliation Testing of Aluminum Alloys

Sprowls, D. O.; Walsh, J. D.; Shumaker, M. B.

doi:10.1520/stp35415s

Cited by 12 publications

(2 citation statements)

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“…The most common accelerated corrosion test used for the aluminum alloys of the 2xxx and 7xxx alloy series is the exfoliation corrosion (EXCO) test according to ASTM G34. It has been reported that 24 h exposure of the aluminum alloy 2024-T4 to the EXCO solution corresponds to nearly 6 years of natural exposure of the same structural element regarding its surface exfoliation [24]. Various mechanical tests had been carried out on AA2024-T3 to assess the effect of the corrosion damage on the material's structural integrity.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the corrosion-induced damage on aluminum alloy 2024 specimens with equivalent surface notches

Alexopoulos

Siskou

Charalampidou

et al. 2019

Frattura Ed Integrità Strutturale

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The effect of corrosion environment aggressiveness on the tensile mechanical properties degradation of AA2024-T3 was investigated. Tensile specimens were pre-corroded for various exposure times to different corrosive solutions, i.e., exfoliation corrosion (EXCO) and 3.5 wt. % NaCl. Then they were tested mechanically. In non-corroded specimens, surface notches of various depths were machined to simulate the degradation of the tensile mechanical properties due to the presence of artificial surface defects. A mechanical model was developed to correlate the corrosion-induced tensile ductility degradation due to pitting and possible hydrogen embrittlement with the equivalent artificially induced surface notches. The cases studied for this physical correlation were: a) EXCO exposure with artificial notches, b) EXCO with 3.5 wt.% NaCl exposure and c) 3.5 wt.% NaCl exposure with artificial notches. Higher correlation was noticed for short exposure times for all cases where the dominant degradation mechanism is slight pitting formation. It was found that 1 h EXCO exposure is equivalent to 92 h exposure to NaCl solution regarding the tensile ductility degradation while 24 h EXCO exposure has the same effect on ductility decrease with a 240 μm surface notch or 4000 h exposure to NaCl solution.

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Section: Introductionmentioning

confidence: 99%

Simulation of the corrosion-induced damage on aluminum alloy 2024 specimens with equivalent surface notches

Alexopoulos

Siskou

Charalampidou

et al. 2019

Frattura Ed Integrità Strutturale

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“…Numerous procedures have been proposed to assess the susceptibility of aluminum alloys to this type of corrosion (e.g. ASSET, MASTMAASIS, EXCO...) 5,6 . Most of them, even widely accepted, give only qualitative results.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Testing of Exfoliation Corrosion Sensitivity of Aluminum Alloys

Marlaud¹,

Malki²,

Deschamps³

et al. 2007

ECS Trans.

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This paper presents an investigation of exfoliation corrosion (EFC) of 7000 series aluminum alloys using a new electrochemical test. For this study two metallurgical states, namely T6 (peak hardness) and T76 (over-aged) of a new high strength 7XXX alloy have been investigated. The experimental protocol consists in a galvanostatic test in an optimized NaCl- NaNO3-AlCl3 electrolyte at pH~4, chosen less aggressive than that used in the standard EXCO test1. The real time fluctuations of the measured potentials, which are expected to contain relevant information on the exfoliation corrosion processes, have been analyzed. SEM observations in the early stages suggest that the measured potential transients are directly related to fracture of surface blisters, commonly evoked in the literature as the predominating mechanism in exfoliation corrosion. This new test opens a new way for quantifying the susceptibility to exfoliation corrosion in aluminum alloys.

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