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arXiv · 1106.0383

Hydrogen in $α$-iron: stress and diffusion

J. Sanchez·J. Fullea·C. Andrade·P. L. de Andres
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Abstract

First-principles density-functional theory has been used to investigate equilibrium geometries, total energies, and diffusion barriers for H as an interstitial impurity absorbed in $α$-Fe. Internal strains/stresses upon hydrogen absorption are a crucial factor to understand preferred absorption sites and diffusion. For high concentrations, H absorbs near the octahedral site favoring a large tetragonal distortion of the BCC lattice. For low concentration, H absorbs near the tetrahedral site minimizing the elastic energy stored on nearby cells. Diffusion paths depend on the concentration regime too; hydrogen diffuses about ten times faster in the distorted BCT lattice. External stresses of several GPa modify barriers by $\approx$ 10%, and diffusion rates by $\approx$ 30%.

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J. Sanchez, J. Fullea, C. Andrade, P. L. de Andres. 2011-06-02. Hydrogen in $α$-iron: stress and diffusion. https://doi.org/10.1103/physrevb.78.014113

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