Study of multivacancies in alpha Fe

Dmytro Kandaskalov (1) , Claude Mijoule (1) , Damien Connétable (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

Formation and migrations energies were calculated for multi-vacancies Vn(n= 1–15) in bcc Fe bulk and its surfaces using density functional theory. In this work, we analyze the evolution of the formation energy, the migration processes and the stable configurations ofVn. For small clusters (mono- and divacancies), our results are in agreement with those from the literature. We also focused on the study of the interactions between surfaces (Fe(1 0 0) and Fe(1 1 0)) and a vacancy, which enabled an assessment of the interactions the between vacancy and free surfaces. For V3, we found that the more compact structure (labeled (11 2)) is a more stable configuration than that ofV4(111122). The migration mechanisms of V2andV3are decomposed to identify the position of the transition states, and to thus explain the low migration energy ofV3. An analysis of the structure of different clusters shows that for n610, the more stable structures are built from 2NN and 1NN divacancies. We suggest some stable compact configurations for large clusters

Mots clés: DFT; Fe alpha; Multivacancies

Domaines: Génie chimique

Dmytro Kandaskalov, Claude Mijoule, Damien Connétable. Study of multivacancies in alpha Fe. Journal of Nuclear Materials, 2013, vol. 441 (n° 1-3), pp. 168-177. ⟨10.1016/j.jnucmat.2013.05.030⟩. ⟨hal-01170461⟩