Stability and mobility of vacancy-H complexes in Al

Benediktsson, MagnúsChalmers tekniska högskola,Chalmers University of Technology (författare)

The effect of hydrogen loading on the stability and mobility of vacancy-H complexes in aluminum is determined by applying DFT and the minimum-mode-following method. The binding energy per H-atom within a complex is found to range from -0.36 eV/atom to -0.34 eV/atom for an occupancy of, respectively, a single and eight H-atoms. When eight H-atoms are neighboring the vacancy the total binding energy becomes -2.72 eV. However, already at a load level of two H-atoms the total binding energy reaches -0.70 eV, which fully compensates the vacancy creation energy. It is observed that for complexes with four or more H-atoms the vacancy gets pinned, as the diffusion barrier increases by a factor of two, reaching a value of 1.03 eV or more. The explanation for the increased energy barrier is that at the higher hydrogen load levels the system must traverse an energetically unfavorable configuration where two or more H-atoms are separated from the vacancy. As a possible consequence of the decreased mobility and increased stability, highly loaded vacancy-H complexes are likely to act as nucleation sites for extended defects.

Myrdal, Kjartan K. G.Lund University,Lunds universitet,Matematikcentrum,Institutioner vid LTH,Lunds Tekniska Högskola,Centre for Mathematical Sciences,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)extLU-29 (författare)
Maurya, PramodIndian Institute of Technology,Háskóli Íslands,University of Iceland (författare)
Pedersen, AndreasHáskóli Íslands,University of Iceland (författare)
Chalmers tekniska högskolaMatematikcentrum (creator_code:org_t)

Ingår i:Journal of Physics Condensed Matter: IOP Publishing25:37, s. 375401-0953-89841361-648X

Av författaren/redakt...: Benediktsson, Ma ...; Myrdal, Kjartan ...; Maurya, Pramod; Pedersen, Andrea ...

Om ämnet

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.