Ab initio study of the modification of elastic properties of alpha-iron by hydrostatic strain and by hydrogen interstitials

Abstract

The effect of hydrostatic strain and of interstitial hydrogen on the elastic properties of $\alpha$-iron is investigated using \textit{ab initio} density-functional theory calculations. We find that the cubic elastic constants and the polycrystalline elastic moduli to a good approximation decrease linearly with increasing hydrogen concentration. This net strength reduction can be partitioned into a strengthening electronic effect which is overcome by a softening volumetric effect. The calculated hydrogen-dependent elastic constants are used to determine the polycrystalline elastic moduli and anisotropic elastic shear moduli. For the key slip planes in $\alpha$-iron, $[1\bar{1}0]$ and $[11\bar{2}]$, we find a shear modulus reduction of approximately 1.6% per at.% H.

Updated first part of 1009.3784

References in corpus (4)

• Dislocation interaction with C in alpha-Fe: a comparison between atomic simulations and elasticity theory
• Hydrogen in $\alpha$-iron: stress and diffusion
• Ab-initio molecular dynamics simulation of hydrogen diffusion in $\alpha$-iron
• First-principles thermoelasticity of bcc iron under pressure

Cited by in corpus (1)

• Ab initio parametrised model of strain-dependent solubility of H in alpha-iron