Abstract
Intergranular stress corrosion cracking in the Al–Mg alloy AA5456-H116 is suppressed via cathodic polarization in 0.6 M NaCl, saturated (5.45 M) NaCl, 2 M MgCl2, and saturated (5 M) MgCl2. Three zones of intergranular stress corrosion cracking (IG-SCC) susceptibility correlate with pitting potentials of unsensitized AA5456-H116 and pure β phase (Al3Mg2) in each solution. These critical potentials reasonably describe the influence of α Al matrix and β phase dissolution rates on IG-SCC severity. Complete inhibition occurred at applied potentials of −1.0 V and −1.1 V versus saturated calomel electrode (V SCE) in 0.6 M NaCl. Whereas only partial mitigation of IG-SCC was achieved at −0.9 V SCE in 0.6 M NaCl and at −0.9, −1.0, and −1.1 V SCE in the more aggressive environments. Correlation of pitting potentials in bulk environments with IG-SCC behavior suggests an effect of bulk environment [Cl−] and pH on the stabilized crack tip chemistry.
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22 June 2017
An erratum to this article has been published.
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Acknowledgement
Funding was provided by the Office of Naval Research (N000 14-15-1-2491) with Dr. Airan Perez as the Scientific Officer.
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An erratum to this article is available at https://doi.org/10.1007/s11837-017-2432-5.
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McMahon, M.E., Scully, J.R. & Burns, J.T. Mitigation of Intergranular Stress Corrosion Cracking in Al–Mg by Electrochemical Potential Control. JOM 69, 1389–1397 (2017). https://doi.org/10.1007/s11837-017-2362-2
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DOI: https://doi.org/10.1007/s11837-017-2362-2