Effect of scratch on crack initiation of alloy 690TT in high temperature high pressure water

Full text of publication follows: This paper aims to investigate the effect of scratch on crack initiation of Alloy 690. The corrosion and stress corrosion of scratched Alloy 690 were studied using scanning electrochemical microscopy (SECM) and scanning electron microscopy (SEM). The results showed that scratch caused residual compressive stress underneath the scratch, dissolution was preferentially active at scratches and intergranular cracks initiated at the bottom of scratch after immersion in high temperature water. At the macro-compressive stressed area, localized tensile stress caused by oxide jacking could initiate crack. (authors)