3D time-resolved observations of corrosion and corrosion-fatigue crack initiation and growth in peak-aged Al 7075 using synchrotron X-ray tomography

摘要

Corrosion fatigue crack initiation and growth from corrosion pits in 7075 aluminium alloys was observed in situ using 3D x-ray synchrotron tomography. Peak-aged Al 7075 was corroded by soaking in 3.5 wt.% NaCl solution, then fatigue tested in situ in the solution using synchrotron X-ray tomography to analyse the corrosion fatigue crack initiation and growth from the pits. Hydrogen bubbles were observed within the intergranular corrosion fatigue cracks, indicating chemical changes in the sample during corrosion fatigue. In situ crack growth, the effect of microstructural constituents on dissolution and growth, and multimodal observations of the fracture surface were conducted and are discussed.