Effect of prior deformation and heat treatment on the corrosion-induced hydrogen trapping in aluminium alloy 2024

• The nature of hydrogen trapping during corrosion in 2024 alloy has been revealed.
• The high temperature (500 °C) trap state is associated with the S-phase (Al2CuMg).
• In the absence of the S-phase, hydrogen is being trapped at vacancies.
• The 400 °C trap state is associated with dislocations.
• High plastic strains lead to a reduction of hydrogen trapped at dislocations and the S-phase.

The nature of the corrosion-induced hydrogen trapping in Al-alloy 2024-T351 was studied by thermal desorption spectroscopy. The microstructure was altered by solution treatment and plastic deformation, prior to corrosion. The results showed that the high temperature, 500 °C, trap state (T4 state) is associated with the S-phase. In the absence of S-phase, hydrogen is trapped at vacancies, which liberate hydrogen at higher temperatures. Plastic deformation prior to corrosion revealed that the trap state at 400 °C (T3 state) is associated with dislocations. High plastic strains (above 0.06) lead to a reduction of hydrogen trapped in both dislocations and the S-phase.