Through-thickness SCC susceptibility of 2024-T351 and 7050-T7451 extrudates in 3.5% NaCl solution

The through-thickness stress corrosion cracking (SCC) behaviors of thick 2024-T351 and 7050-T7451 extrudates in 3.5% NaCl solution were studied at both anodic and cathodic applied potentials using a slow strain rate test method. The SCC susceptibilities of 2024-T351 extrudate tended to change in the throughthickness direction, with the lowest susceptibility for the surface specimen. 7050-T7451 specimens, on the other hand, did not show a notable change in the through-thickness SCC susceptibility. The fractographic analysis suggested that the grain boundary played an important role in determining the SCC susceptibility. The SCC process of each alloy was discussed based on the microscopic and fractographic examinations.