Effect of hydrogen on electronic structure of fcc iron in relation to hydrogen embrittlement of austenitic steels

• Published in: Physica status solidi. A, Applications and materials science Vol. 204; no. 12; pp. 4249 - 4258
• Main Authors: Teus, S. M., Shivanyuk, V. N., Shanina, B. D., Gavriljuk, V. G.
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01-12-2007; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: 61.72.Ji; 61.72.Lk; 62.20.Mk; 71.15.Mb; 71.20.Be; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Elasticity, elastic constants; Electron density of states and band structure of crystalline solids; Electron states; Exact sciences and technology; Fatigue, brittleness, fracture, and cracks; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Physics; Transition metals and alloys; Elastic modulus; Total energy; FCC lattices; Shear modulus; Conduction electron; Electronic density of states; Electronic structure; Spatial distribution; Solid solutions; Austenitic steels; Primitive cell; Density functional method; Hydrogen charging; Lattice energy; Hydrogen embrittlement
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.200723249

The total structural energy per primitive lattice cell, density of electron states, spatial distribution of electrons and elastic modulus in fcc Fe–H solid solutions are studied using the density functional theory and Wien2k program package. It is shown that hydrogen increases the density of electron states at the Fermi level. The density of conduction electrons is increased in the vicinity of hydrogen atoms, which suggests that the latter migrate over the crystal lattice surrounded by the clouds of conduction electrons. Calculations of elastic modulus show that hydrogen decreases the shear modulus c44. The consequences for mechanical properties of hydrogen‐charged austenitic steels are analysed taking into account the stress for activation of dislocation sources, the line tension of dislocations and the distance between dislocations in pile‐ups. It is concluded that hydrogen‐induced brittleness of austenitic steels can be satisfactorily interpreted in terms of the hydrogen effect on the electronic structure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)