Bonn 2025 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 20: Poster – Atomic Clusters
A 20.1: Poster
Mittwoch, 12. März 2025, 17:00–19:00, Tent
Ab-initio study of the transition pathways for single and double interstital solute (H, N, O, H-H, N-N and O-O) within bcc refractory metals (Mo and Nb) — •Henry Elorm Quarshie1, Henry Martin1,2, Eric Kwabena Kyeh Abavare1, and Alessandra Continenza3 — 1Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana — 2Center for Scientific and Technical Computing, National Institute for Mathematical Sciences, Kumasi, Ghana — 3Dipartimento di Scienze Fisiche e Chimiche, Universita degli studi dell’Aquila, L’Aquila, Italy
This study investigates the diffusion pathways of single (H, N, O) and double (H-H, N-N, O-O) interstitial solutes in bcc molybdenum (Mo) and niobium (Nb). The aim is to understand how atmospheric gases rich in H, O, and N interact with metals. Ab-initio calculations were performed to determine equilibrium parameters, dissolution energetics, charge transfer, minimum energy paths, and diffusion coefficients. Single solutes exhibited site preferences, with H favouring tetrahedral sites (t-sites), N preferring octahedral sites (o-sites), and O showing material-dependent behaviour linked to the deformation behaviour of Mo and Nb. Diffusion energy barriers ranged from 0.10 eV to 1.34 eV, aligning with experimental results. The study also examined double interstitial solutes and found that a second solute significantly reduces activation energies, enhancing diffusion in most configurations, except for Mo-O. This effect is due to the second solute’s influence on local lattice relaxations and interstitial interactions. The work further reveals that a second solute can alter the preferred diffusion pathways.
Keywords: Activation energies; Diffusion; Interstitial; Solute; Lattice distortion