Modelling mixed 1d/3d diffusion of radiation defects in elastic fields: case study on bcc metals Fe and V

A method for modeling the diffusion of radiation defects (RD) with a mixed 1D/3D diffusion mechanism (the defect migrates one-dimensionally, occasionally changing the direction of its one-dimensional migration) in inhomogeneous elastic fields is proposed based on the object kinetic Monte Carlo method. Within this method, the influence of the elastic field on the frequencies of direction changes in RD migration and on the frequencies of their jumps along one-dimensional directions is taken into account using dipole tensors of the corresponding saddle configurations of RD within the framework of anisotropic linear elasticity theory. Such dipole tensors are defined based on the analysis of molecular dynamics data on RD diffusion in homogeneous elastic fields using the developed kinetic model. Using the proposed method, the dependencies dislocations sink strengths for di-interstitials as a function of temperature (in the range of 293–1000 K) and dislocation density (in the range of 1014–1015 m-2) in BCC metals Fe and V have been calculated. Straight full screw and edge dislocations in slip systems ⟨111⟩{110}, ⟨111⟩{112}, ⟨100⟩{100}, ⟨100⟩{110} are considered. Analytical expressions approximating the calculated dependencies of sink strengths of dislocations on temperature and dislocation density are proposed.