The stress corrosion cracking (SCC) of underaged, peakaged and overaged Al 7010 in either water vapour saturated air (WVSA) or in salt water has been investigated using transmission electron microscopy (TEM). The crack tip and near crack tip regions formed in Double Cantilever Beam (DCB) samples are described. A range of behaviours will be outlined in relation to the observed grain boundary microstructures and it will be shown that fracture is caused by either pure mechanical
rupture, pure corrosion or SCC. Keywords: stress corrosion cracking, 7XXX series, aluminium alloys, water vapour saturated air, salt water, NaCl, transmission electron microscopy, double cantilever beam.