Strain field of interstitial hydrogen atom in body-centered cubic iron and its effect on hydrogen–dislocation interaction

The effect of hydrogen in body-centered cubic iron is explored by using the density function theory. Hydrogen atoms increase the concentration of free electrons in the simulation cell and undergo bonding interaction with Fe atoms. Elastic interaction between hydrogen and screw dislocations was found, caused by the anisotropic strain components of the hydrogen atoms in the tetrahedral sites. The dependence of the hydrogen–screw dislocation interaction on hydrogen concentration is confirmed by repeated stress relaxation tests.