Stress Corrosion Cracking Caused by Passive Film-Induced Tensile Stress Available to Purchase

α-Ti foil with a protective layer formed on one side was deflected as a result of corrosion in a methanol (CH₃OH) solution containing 0.6 mol/L potassium chloride (KCl) because of tensile stresses generated at or near the metal passive film interface. Transmission electron microscopy (TEM) observations showed that the corrosion process could facilitate dislocation emission and motion. A laser moire interferometer measurement indicated that the corrosion process could enhance the plasticity ahead of a notch tip of a thick specimen. The film-induced tensile stress possibly can assist the applied stress to facilitate dislocation emission and motion (i.e., plasticity). TEM observations showed that when the corrosion-facilitated dislocation emission and motion developed to a critical condition, microcracks of stress corrosion cracking (SCC) would nucleate. With 10% H₂O in the methanol solution, the passive film-induced stress decreased from 320 MPa to 0, and the susceptibility to SCC (relative plasticity loss) measured in slow strain rate tests decreased correspondingly from 98% to 0.