Influence of stress fields of dislocations on formation and spatial stability of point defects (elastic dipoles) in V and Fe crystals

Abstract

Formation energies, dipole forces and crystallographic characteristics of point defects (vacancies and self-interstitial atoms) as elastic dipoles of different symmetry were defined for bcc V and Fe crystals by computer simulation methods with use of modified interatomic interaction potentials. Stress fields and energy factors of screw, mixed (45°) and edge dislocations in basic slip system of V and Fe crystals 〈1 1 1〉{1 1 0} were calculated in the framework of the anisotropic theory of elasticity. Elastic interaction energies of the above mentioned point defects and dislocations were calculated and the essential influence of these interactions (for vacancies via their saddle point positions especially) on formation energies, crystallographic configurations (stable and unstable) and diffusion ways of point defects was shown. Critical densities of dislocations were defined, at which their stress fields control the thermal mobility of point defects throughout the whole crystal volume.