Multiscale correlative characterization of environmentally assisted crack initiation, propagation and failure in a high strength AA5083 H131 alloy

Environmentally assisted cracking in a high strength AA5083 H131 alloy has been investigated using a multiscale correlative characterization approach to understand the surface intergranular corrosion to environmentally assisted crack (EAC) transition. Time-lapse 3D synchrotron X-ray tomography was employed during slow strain testing of a sensitized AA5083 sample sensitized at 80 °C for 250 h. In addition, several of the specimens tested were pre-exposed to a chloride containing environment to induce corrosion sites which could act as ‘realistic’ stress raisers in the subsequent straining. Reconstructed volumes of the X-ray CT time-lapse series allowed us to track and follow crack propagation in the material during slow strain rate testing at high resolution \u3c5 µm. Volumes of interest from the test samples identified from the X-ray CT reconstructions were further analyzed post-mortem using electron microscopy and spectroscopy based techniques to study the presence and chemistry of secondary phases such as those based on Mg-Si, and their role in the initiation, propagation and/or arrest of crack tips/fronts