Hydrogen solubility, diffusion and trapping in high purity aluminum and selected Al-base alloys

A review of experimental measurements of hydrogen solubility, diffusivity, and trapping in polycrystalline aluminum and selected Al-base precipitation age hardened materials is presented. There is widespread variability in experimentally measured effective diffusion coefficients and apparent solubilities in high purity aluminum and Al-alloys due to the sensitivity of test methods to surface oxides and hydrogen trapping at microstructural defects. Therefore, few measurements yield perfect lattice diffusivities and solubilities. This paper provides a compilation of available literature and presents some new data. Specifically, hydrogen interactions in high purity Al, AI-Li and AI-Cu binary alloys, Al-Li-Cu-Zr (AA 2090), Al-Cu-Mg (AA 2024), Al-Zn-Mg-Cu (AA 7075), and Al-Zn-Mg-Cu-Zr (AA 7050 and a low copper variant of AA 7050) alloys are reported. Several hydrogen trapping states are identified including dislocations, the distorted zone around vacancies, Li in solid solution, and specific precipitate phases.