Abstract
The effects of hydrogen impurities in the bulk and on the surface of aluminum are theoretically investigated. Within the framework of density-functional theory, we have obtained the dependence on H concentration of the stacking fault energy, the cleavage energy, the Al/H surface energy, and the Al/H/Al interface formation energy. The results indicate a strong dependence of the slip energy barrier in the direction, the cleavage energy in the [111] direction and the Al/H/Al interface formation energy, on H concentration and on tension. The dependence of the Al/H surface energy on H coverage is less pronounced, while the optimal H coverage is ⩽0.25 ML. The calculated activation energy for diffusion between high-symmetry sites in the bulk and on the surface is practically the same, 0.167 eV. From these results, we draw conclusions about the possible effect of H impurities on mechanical properties and, in particular, on their role in embrittlement of Al.
- Received 6 September 2001
DOI:https://doi.org/10.1103/PhysRevB.65.064102
©2002 American Physical Society