55 Application of Kelvin Force Microscopy Measurements and Secondary Ion Mass Spectroscopy to Evidence Hydrogen Embrittlement for the 2024 Aluminum Alloy

The present study focuses on the application of Kelvin Force Microscopy (KFM) measurements combined to Secondary Ion Mass Spectroscopy (SIMS) to the detection and localization of hydrogen in a pre-corroded 2024-T351 aluminum alloy. To demonstrate the role of hydrogen on cyclic corrosion damage (cold cycling corrosion test, CC test, corresponding to 3 cycles constituted of a 8 h immersion in 1M NaCl followed by a 16 h air exposure period at -20°C), KFM measurements were performed; the results obtained on CC samples were compared to those obtained on a cathodically hydrogen charged sample. Results showed the hydrogen penetration along the grain boundaries and the subgrain boundaries of the pre-corroded CC samples. SIMS analyses corroborated the results so that the combination of KFM measurements and SIMS analyses was helpful in showing the contribution of hydrogen to the 2024 alloy damage following exposure to a corrosive medium.