Ab‑initio study of the transition pathways for single and double interstitial solute (H, N, O, H‑H, N‑N, and O‑O) within bcc refractory metals (Mo and Nb)
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Date
2024-11
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Springer
Abstract
Transition pathways of single (Hydrogen (H), Nitrogen (N), and Oxygen (O)) and double (H-H, N-N and O-O) interstitial
solutes within bcc refractory metals (molybdenum (Mo) and niobium (Nb)) were investigated. This work is crucial for
understanding how atmospheric gases, rich in H, O, and N, interact with metals. Ab-initio calculations for equilibrium
and structural parameters, dissolution energetics, charge transfers, minimum energy path, and difusion coefcients were
performed. Single solutes exhibited preferential occupancy sites, with H favoring tetrahedral sites (t-sites), N preferring
octahedral sites (o-sites), and O showing material-dependent behavior. The energy barriers for single solute difusion ranged
from 0.10 to 1.34 eV, aligning with experimental fndings. Double interstitial solutes signifcantly reduced activation energies
(Ea), leading to faster difusion for all confgurations except for MoO. This efect is due to the second solute’s infuence on
repulsive/attractive forces and local lattice relaxations, altering preferred difusion pathways.
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This article is published by Springer 2024, and is also available at https://doi.org/10.1557/s43580-024-01028-3