Correlations between stress corrosion cracking susceptibility and grain boundary microstructures for an Al-Zn-Mg alloy

The correlations between grain boundary precipitates (GBPs) area fraction and stress corrosion cracking (SCC) susceptibility for an Al-Zn-Mg alloy have been studied using TEM statistical investigations and image analysis. The results reveal that SCC susceptibility of the Al-Zn-Mg alloy first decreases and then increases with the increase of GBPs area fraction, which does not agree with Dix's anodic dissolution theory, suggesting that SCC of the Al-Zn-Mg alloy is dominated by hydrogen induced cracking when GBPs area fraction is relatively low and is dominated by anodic dissolution when GBPs area fraction is relatively high. (C) 2013 Elsevier Ltd. All rights reserved.