Effect of static mechanical load on intergranular stress-corrosion cracking of 7050-T7451 C-Ring specimens

摘要

In this paper, 7050-T7451 C-Ring stress-corrosion alternate immersion test in neutral 3.5% NaCl solution was conducted to investigate the mechanism of stress-corrosion cracking (SCC). The SCC sequence was proved to comprise dealloying, pitting, micro-cracks, and intergranular (IG) cracks. Besides, anodic dissolution characterised by reticular IG cracks within pitting zones and IG Dimple Rupture is suggested to be the main operative mechanism during this static stress-corrosion process. Since pitting originates from coarse constituents whose number can be reduced by optimised solution treatment, the formation of pitting can, therefore, be delayed by adopting more effective solution treatment before artificial aging to enhance the SCC resistance.