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
2024-12
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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 diffusion coefficients 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 diffusion ranged
from 0.10 to 1.34 eV, aligning with experimental findings. Double interstitial solutes significantly reduced activation energies
(Ea ), leading to faster diffusion for all configurations except for MoO. This effect is due to the second solute’s influence on
repulsive/attractive forces and local lattice relaxations, altering preferred diffusion pathways.
Description
This article is published by Springer 2024 and is available at https://doi.org/10.1557/s43580-024-01028-3
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Citation
H. E. Quarshie et al.