The evaluation of the critical electrochemical potentials influencing environmentally assisted cracking of Al-Li-Cu alloys in selected environments

Wall, F. D.; Stoner, G. E.

doi:10.1016/s0010-938x(97)81154-7

Cited by 28 publications

(23 citation statements)

References 7 publications

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“…For the Al-Li-Cu alloy 2090, two key features were proposed: stress-assisted anodic dissolution of the T 1 phase being active with respect to the region near subgrain boundaries and the formation of passive films along crack walls [125]. In a further study built upon these data conducting constant extension-scratching electrode experiments, similar results were obtained for Al-Li-Cu and Al-Cu-Mg alloys, supporting the assumption that the electrochemistry of the copper depleted region along grain boundaries is the active path in an anodic dissolution mechanism [129].…”

Section: +mentioning

confidence: 65%

Environmentally assisted cracking of aluminium alloys

Braun

2007

Materialwissenschaft Werkst

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Dedicated to Prof. Wolfgang Bunk on the occasion of his 80 th birthdayA short review of the stress corrosion cracking (SCC) behaviour of aluminium alloys is given. Mechanisms of environmentally assisted cracking are outlined. For aluminium alloys, in which stress corrosion cracks propagate predominantly along grain boundaries, anodic dissolution and hydrogen embrittlement have been proposed. Transgranular stress corrosion cracking occurring at severe loading conditions has found particular interest concerning localised corrosion-deformation interactions. Accelerated test methods for assessing the SCC behaviour are described, including the slow strain rate testing technique and the breaking load method. Results of recent studies on environmentally assisted cracking of aluminium alloys are summarised. Most of the work published in the last two decades has been on aluminium-lithium based alloys and improved high strength Al-Zn-Mg-Cu alloys in corrosion resistant retrogressed and re-aged tempers.Keywords: aluminium alloys, stress corrosion cracking, anodic dissolution, hydrogen embrittlement, testing methods

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Section: +mentioning

confidence: 65%

Environmentally assisted cracking of aluminium alloys

Braun

2007

Materialwissenschaft Werkst

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“…For Al-Li-Cu alloys, results of electrochemical studies supported an anodic dissolution mechanism of environmentally assisted cracking. Susceptibility was attributed to selective dissolution of T 1 phase precipitated on grain and subgrain boundaries as well as of a copper depleted zone along grain boundaries [14,25]. In tempers being sensitive to stress corrosion cracking, Al-Li-Cu-Mg alloys, such as 8090 and 2091, were found to be also sensitive to intergranular corrosion [23,28].…”

Section: Discussionmentioning

confidence: 99%

Stress corrosion cracking behaviour of Al‐Li alloy 8090‐T8171 plate exposed to various synthetic environments

Braun¹

2004

Materials & Corrosion

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The stress corrosion cracking (SCC) behaviour of 8090‐T8171 plate material was investigated in short transverse direction performing constant load tests and constant extension rate tests under permanent immersion conditions. At an applied stress of 100 MPa, smooth round tensile specimens were exposed to synthetic environments containing chlorides and various nonhalide anions. Environment‐induced cracking was not observed in aqueous solutions of 0.6 M NaCl, LiCl, NH4Cl, or MgCl2. In 0.6 M NaCl solutions containing 0.06 M Na2SO4 or Na3PO4, the SCC behaviour of 8090‐T8171 plate was similar to that observed in pure 0.6 M NaCl solution. Sodium chloride solutions with additions of nitrate, hydrogen carbonate, or carbonate promoted stress corrosion cracking. Threshold stresses below 100 MPa were obtained from constant load tests using the latter environments. When sodium sulfite or sodium hydrogen phosphate was added, values being 100 MPa or slightly higher were determined. Lithium and ammonium present as cations in mixed salt electrolytes accelerated SCC failure. Lithium chloride solutions containing nitrate, hydrogen carbonate, carbonate, or sulfite were highly conducive to stress corrosion cracking. Very low SCC resistance was found for alloy 8090‐T8171 exposed to synthetic environments with additions of ammonium salts. Constant extension rate tests were carried out using notched tensile specimens. Displacement rates were in the range 2 × 10−6 − 2 × 10−5 mms−1. Aqueous 0.6 M NaCl solutions with additions of 0.06 M NH4HCO3, (NH4)2SO4, or Li2CO3 promoted environment‐induced cracking with 8090‐T8171 plate, as indicated by severe degradation of notch strength. The constant extension rate testing technique did not indicate SCC susceptibility using sodium chloride solutions containing sodium sulfate or lithium sulfate. For specimens exposed to substitute ocean water a slight degradation of notch strength was found at the lowest displacement rate applied.

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“…However, the alloy is susceptible to various forms of localized corrosion in chloride environments, such as pitting, crevice, intergranular corrosion and exfoliation corrosion. Localized corrosion of Al alloys in aqueous chloride solutions has been investigated using different techniques [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Investigation of corrosion behaviour of hydrogenated 7075-T6 aluminum alloy

El-Amoush¹

2007

Journal of Alloys and Compounds

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The evaluation of the critical electrochemical potentials influencing environmentally assisted cracking of Al-Li-Cu alloys in selected environments

Cited by 28 publications

References 7 publications

Environmentally assisted cracking of aluminium alloys

Environmentally assisted cracking of aluminium alloys

Stress corrosion cracking behaviour of Al‐Li alloy 8090‐T8171 plate exposed to various synthetic environments

Investigation of corrosion behaviour of hydrogenated 7075-T6 aluminum alloy

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