| This investigation is focused on the evaluation of stress corrosion cracking (SCC), hydrogen embrittlement (HE) and localized corrosion (pitting and crevice) susceptibility of zircaloy-2 and zircaloy-4 in neutral and acidic solutions at 30, 60, 90°C. Constant-load and slow-strain-rate (SSR) testing methods were used to evaluate the SCC and HE behavior of both alloys by use of smooth and notched tensile specimens. Controlled cathodic potentials were applied to evaluate the hydrogen effect on the cracking behavior. Cyclic potentiodynamic polarization technique was used to determine the localized corrosion susceptibility. The metallography and morphology of failure were analyzed by optical microscopy and scanning electron microscopy (SEM), respectively. No cracking was observed under constant loading. However, the SSR testing revealed enhanced ductility and reduced failure stresses with increasing temperature. These effects were more pronounced under cathodic charging. All polarization specimens showed signs of general dissolution but no classical pits or crevices. Fractographic evaluations by SEM revealed dimpled microstructure indicating ductile failures. |
