Abstract
Various data provided by the slow strain rate technique have been examined to determine the most suitable criteria for quantifying stress corrosion cracking susceptibility of an Al-Zn-Mg alloy in the long transverse direction in a chloride-containing aqueous solution. Fracture energy and elongation at fracture ratios appear to be the most convenient criteria, particularly for showing the effect of aging time on SCC susceptibility. Other criteria such as maximum load ratio and reduction of area appear to be insensitive or inappropriate. A method is proposed for the determination of Stage II crack growth rate (i.e., where crack growth rate is independent of stress intensity factor). This crack growth rate also appears to be a good criterion but insensitive with respect to the lowest SCC susceptibilities.
