Ab initio calculation of total energy of a bcc iron cell containing three dissolved carbon atoms, and internal friction in Fe–C solid solutions

Abstract

Carbon interstitial atoms, when dissolved in bcc Fe, induce elastic dipoles with tetragonal symmetry. Mechanical loss spectra indicate the presence of interstitial atoms by Snoek peaks. The magnitude of the peaks is proportional to the concentration of interstitial atoms in solution and the dipole strength. The ab initio computer simulation of lattice parameters and local structure distortions caused by the Fe–C system with three carbon atoms in different octahedral positions of one sublattice has been carried out using WIEN2k software. The simulation results allowed us to propose a way to estimate the dipole strength. The value found are λ1- λ2 = 0.58.