This work aims at determining the influence of hydrogen on the corrosion damage of 2024 aluminum alloy (AA 2024), a commonly used alloy in aeronautics. A powerful way to study hydrogen embrittlement at a local scale is by Scanning Kelvin Probe Force Microscopy (SKPFM). This technique by measuring the surface potential at the nanometer scale allows the detection and localization of hydrogen in the alloy. Firstly SKPFM measurements were taken on an AA 2024 alloy H-charged by cathodic charging in H2SO4. SKPFM images taken on the side perpendicular to the charging side revealed a surface potential gradient over a few hundreds of microns due to a hydrogen gradient in the material. After heat treatment at 130 °C, the gradient disappeared suggesting the complete desorption of hydrogen. The SKPFM technique was then used to detect hydrogen in the corrosion defect of the 2024 aluminum alloy exposed to a 1 M NaCl solution. By imaging heat treated corroded samples by SKPFM, the presence of hydrogen trapped at different energy sites was confirmed. These results show the potential of SKPFM as an innovative method to study the mechanisms of hydrogen embrittlement at the corrosion defect scale.

Subject
Materials, Polishing, Sodium chloride, Corrosion detection, Desorption, Mechanical properties, Sodium chloride solution, Defects, Immersion, Aluminum alloys, Grain boundary, Heat treatment, Hydrogen
Keywords:
Aluminum alloys, Hydrogen desorption, Scanning Kelvin Probe Force Microscopy (SKPFM), Intergranular corrosion, Hydrogen embrittlement
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2017
Association for Materials Protection and Performance (AMPP)
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