This work reports an electrochemical investigation of corrosion and repassivation in NaCl solutions of structural Al 7075-T6 and Al 2024-T3 as a function of permanent load in bending by means of single-cycle anodic polarization. Experimental variables other than the load level were the extent of corrosion, chloride ion concentration and initial pH of the test solution, in addition to the pre-exposure in the aggressive environment and of the viscosity of the test solution for Al 7075-T6. The susceptibility to local stress during corrosion and repassivation depends on the alloy microstructure and corrosion mechanisms. In the case of Al 2024-T3, the mechanical activation is driven by cathodically controlled dissolution of this alloy at open circuit in concentrated NaCl, being indicative of a chemomechanical effect. Conversely, for Al 7075-T6, the effect of applied load is better discerned from the repassivation response. Film rupture/formation sequence and related interfacial (electro)chemical processes determine the stress-enhanced metastable repassivation of this alloy.

Electrochemical investigation of corrosion and repassivation of structural aluminum alloys under permanent load in bending / M. Ferri, M. Trueba, S.P. Trasatti, M. Cabrini, A. Lo Conte. - In: CORROSION REVIEWS. - ISSN 0334-6005. - 35:4-5(2017 Oct), pp. 225-239. ((Intervento presentato al convegno International Symposium on Environmental Degradation under Static and Cyclic Loads in Structural Metallic Materials at Ambient Temperatures IV : 29th May - 3rd June tenutosi a Cork (Ireland) nel 2016.

Electrochemical investigation of corrosion and repassivation of structural aluminum alloys under permanent load in bending

M. Ferri;M. Trueba
;
S.P. Trasatti;
2017

Abstract

This work reports an electrochemical investigation of corrosion and repassivation in NaCl solutions of structural Al 7075-T6 and Al 2024-T3 as a function of permanent load in bending by means of single-cycle anodic polarization. Experimental variables other than the load level were the extent of corrosion, chloride ion concentration and initial pH of the test solution, in addition to the pre-exposure in the aggressive environment and of the viscosity of the test solution for Al 7075-T6. The susceptibility to local stress during corrosion and repassivation depends on the alloy microstructure and corrosion mechanisms. In the case of Al 2024-T3, the mechanical activation is driven by cathodically controlled dissolution of this alloy at open circuit in concentrated NaCl, being indicative of a chemomechanical effect. Conversely, for Al 7075-T6, the effect of applied load is better discerned from the repassivation response. Film rupture/formation sequence and related interfacial (electro)chemical processes determine the stress-enhanced metastable repassivation of this alloy.
Al alloys; bending load; electrochemistry; repassivation
Settore ING-IND/22 - Scienza e Tecnologia dei Materiali
Settore ING-IND/23 - Chimica Fisica Applicata
15-ago-2017
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/551203
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