ZrLavesphaseswithternaryadditions:ADFTstudy EnergeticsofatomichydrogenabsorptioninC15-Fe ScienceDirect

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Review Article

Energetics of atomic hydrogen absorption in

C15-Fe ₂ Zr Laves phases with ternary additions: A DFT study

L. Rabahi

^a,b,^*

, M. Gallouze

^c

, T. Grosdidier

^d

, D. Bradai

^a

, A. Kellou

^c,d

aLaboratoire de Physique des Materiaux, Faculte de Physique, USTHB, BP 32 El Alia, 16111, Bab Ezzouar, Alger, Algeria

bResearch Center in Industrial Technologies CRTI, P.O. Box 64, Cheraga, 16014, Algiers, Algeria

cLaboratoire de Physique Theorique, Faculte de Physique, USTHB, BP 32 El Alia, 16111, Bab Ezzouar, Alger, Algeria

dLaboratoire d'Etude des Microstructures et de Mecanique des Materiaux (LEM3), Laboratoire d'Excellence Design des Alliages Metalliques pour Allegement de Structures (Labex DAMAS), Ile du Saulcy, F-57045, MetzeCedex 01, France

a r t i c l e i n f o

Article history:

Received 28 July 2016 Received in revised form 14 November 2016

Accepted 18 November 2016 Available online xxx Keywords:

Laves phases Hydrogen absorption Atomic defects Relative stability DFT

a b s t r a c t

The pseudo-potential Density Functional Theory (DFT) method using the Generalized Gradient Approximation (GGA) was applied to investigate hydrogen absorption trends in the cubic C15-ZrFe2Laves phase in the presence of several ternary additions. The effect of the ternary addition on the stability of the Laves phase was investigated. The relative stability of atomic hydrogen at various interstitial sites was determined taking into account the type of ternary addition for different H contents in the hydrides. The results were analyzed and particular attention was given to the formation and binding energies of hydrogen. It was found that hydrogen prefers the96gsite in the clean C15-Fe2Zr, and its absorption leads to decrease the heat of formation of the formed hydrides with occurrence of phase separation around 6H/fu.This effect was enhanced by the presence of ternary additions. Moreover, alloys with Be, V, Cr, Mn, Y and Tc elements at the Fe sites were found to absorb hydrogen up to 6H/fu.More interestingly, the cohesion of hydrogen atoms was found to be very sensitive to the third element nature. The hydrides with V, Y, and more particularly Tc and Ru have exhibited interesting energetics which would be very attractive for practical applications.

ScienceDirect

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / h e i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 6 ) 1e1 0

http://dx.doi.org/10.1016/j.ijhydene.2016.11.131

Please cite this article in press as: Rabahi L, et al., Energetics of atomic hydrogen absorption in C15-Fe2Zr Laves phases with ternary additions: A DFT study, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.11.131