First-principles study of the insertion and diffusion of interstitial atoms (H, C, N and O) in nickel

Matthieu David (1) , Aurélien Prillieux (2) , Daniel Monceau (1) , Damien Connétable (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 School of Materials Science and Engineering

Solubility and diffusivity of interstitials in Ni is of prime importance to understand and quantify reactivity of Ni-base structural alloysat high temperature. We thus present a first-principles study of the insertion and diffusivity of interstitial species in nickel. We put an emphasis on carbon, nitrogen and oxygen atoms and compare our results with those found for hydrogen and in the literature. The interactions with the metal and the relative stability of sites are discussed in detail in terms of phonon, electronic, elastic, magnetic properties and charge transfers. As a result, we identified one new stable interstitial position for C and N atoms, and we also showed that the tetrahedral site can be considered as unstable from an elastic standpoint for carbon. In the light of these new results, diffusion mechanisms were reviewed and diffusion coefficients were calculated. The effects of temperature on enthalpy and migration energies were investigated. We thus showed that C and N atoms on one hand, H and O atoms on the other hand, show the same behavior.

Mots clés: Nickel; interstitial species; DFT; diffusion; solubility

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Matthieu David, Aurélien Prillieux, Daniel Monceau, Damien Connétable. First-principles study of the insertion and diffusion of interstitial atoms (H, C, N and O) in nickel. Journal of Alloys and Compounds, 2020, 822, pp.153555. ⟨10.1016/j.jallcom.2019.153555⟩. ⟨hal-02417210⟩