Methodology for a mechano-electrochemical evaluation of the coupling at the crack tip. Application of halide-induced Stress Corrosion Cracking of Zircaloy-4

• Digital Image Correlation controlled pre-cracking and pre-oxidation were carried out to study Stress Corrosion Cracking.
• Localized dissolution at crack tip for Zircaloy-4 in halide solutions was evaluated.
• Synergetic processes at crack tip were studied by Digital Image Correlation and electrochemical methods.
• The evaluation of the dissolved metal at the crack tip allowed validating the proposed approach.

In order to evaluate the relative contribution of both mechanical and electrochemical processes at the crack tip during Stress Corrosion Cracking propagation, an original combination of controlled pre-cracking followed by thermal pre-oxidation of SCC specimens was developed. It allowed localizing dissolution at the crack tip for Zircaloy-4 tested in halide solutions under potentiostatic polarization. Digital Image Correlation and electrochemical methods were then carried out to study correlations between the stress intensity factor, the crack length and the measurements of dissolution current.