Influence of hydrogen vacancy interactions on natural and artificial ageing of an AlMgSi alloy

Hydrogen delaying the formation of Guinier-Preston zones in aluminium alloys

“…Complementary information is detailed in Appendix A where DSC measurements have been performed on this alloy differently aged. Hydrogen strongly interacts with excess vacancies [33,[38][39][40], and thus seems to delay the formation of GP zones probably by reducing the diffusion of copper or/and by increasing the energy barrier of GP zones nucleation. Ab initio calculations are then carried out to get a deeper understanding of fundamental mechanisms leading to the delayed formation of GP zones when hydrogen is introduced on the alloy.…”

“…This difference can be due to hydrogen reducing the diffusion of copper or/and an increase of the energy barrier to form GP zones, locking copper agglomerates as clusters. Since hydrogen strongly interacts with the excess vacancies [33,[38][39][40], our numerical study focused on the effect of hydrogen on the diffusion of the copper in aluminium through ab initio calculations. .…”

“…Previous studies focusing on the hydrogen/vacancy interactions in metals have shown that hydrogen decreases the formation energy of vacancy clusters containing hydrogen [33,37] and the vacancy migration energy [39]. Hydrogen may also delay the clustering of solutes and the coarsening of precipitates in some Al alloys [35,40]. Therefore, it is critical to understand how these interactions impact the kinetic and thermodynamic of precipitates in aluminium alloys (which may evolve even at room temperature) to predict microstructural evolutions and eventually to reduce the damaging effect of hydrogen.…”