Atomistic investigation on the impact of substitutional Al and Si atoms on the carbon kinetics in ferrite

Liangzhao Huang (1) , Paul Eyméoud (1) , Philippe Maugis (1)

1 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence

The pairwise interactions of substitutional solute atom X = Al, Si with interstitial carbon at stable (octahedral) and saddle-point (tetrahedral) positions in body-centered-cubic iron (α-Fe) are computed using density-functional theory. These pairwise interactions are used in atomistic kinetic Monte Carlo approach to simulate carbon internal friction and tracer diffusion measurements in Fe-Si, Fe-Al, and Fe-Al-Si ferritic alloys without any adjusting parameters. The good agreement between the simulated and experimental Snoek relaxation profiles validates the pair interaction model for kinetic simulations. The predicted effect of Al on slowing down carbon diffusion is consistent with previous studies. We highlight a super-cell size effect on the Si-carbon interactions obtained from first principles. Using a carefully tested database, it is shown that the introduction of Si into ferrite only decreases the carbon diffusivity below a critical temperature.

Mots clés: Internal friction; tracer diffusion; first principles; Monte Carlo; Fe-Si-C; Fe-Al-C; Fe-Al-Si-C

Domaines: Physique [physics]; Science des matériaux [cond-mat.mtrl-sci]; Mécanique statistique [cond-mat.stat-mech]

Liangzhao Huang, Paul Eyméoud, Philippe Maugis. Atomistic investigation on the impact of substitutional Al and Si atoms on the carbon kinetics in ferrite. 2022. ⟨hal-03711503⟩