Bond-order potential for point and extended defect simulations in tungsten

Abstract

A reactive interatomic bond-order potential for bcc tungsten is presented. Special attention in the potential development was given for obtaining accurate formation and migration energies for point defects, making the potential useful in atomic scale simulations of point and extended defects. The potential was used to calculate binding energies and trapping distances for vacancies in vacancy clusters and the recombination radius for self-interstitial atom and monovacancy.

Cluster dynamics modeling of accumulation and diffusion of helium in neutron irradiated tungsten

“…1a) derived from the capillary law approximation with E f I ¼ 9:466 eV [31] and E b I 2 ¼ 2:12 eV [16] are in reasonably good agreement with the ab initio results and also with the expression given by the elasticity theory of dislocations with neglecting the small edge core term [32]. For a vacancy (He atom) with a vacancy (He) cluster, two sets of the binding energy versus the size of cluster based on MD [29,33] and ab initio [15,16] calculations are shown in Fig. 1(b) and (c).…”

“…1(b) and (c). The MD calculation results [33] including the influence of high temperature for vacancy with E f V ¼ 3:80 eV [31,34], and E b V 2 ¼ 0:6559 eV [29,33] and the ab initio calculation results [15,16] for He atom with E f He ¼ 4:0 eV and E b He 2 ¼ 1:02 eV are used here and extended with the capillary law approximation for large clusters. The binding energy of a He atom or vacancy with He m V n complexes (He + He m V n He m+1 V n ; V + He m V n He m V n+1 ) as obtained by ab initio calculation for clusters up to size of 23 has been presented in reference [16].…”

“…Binding energy of (a) a SIA/vacancy with an interstitial loop, (b) a vacancy with a vacancy cluster and (c) a He atom with a He cluster versus the size of the loop/cluster calculated by the capillary law approximation/elastic theory[32] and obtained from MD/ab initio calculations[15,16,29,33].…”

Recent progress in research on tungsten materials for nuclear fusion applications in Europe

“…The implantation time, dose and temperature used in the RE simulations were taken from the experimental set-up. The primary D-W irradiation-induced collision statistics were determined by binary collision approximation calculations with SRIM and the W collision cascades by Molecular Dynamics (MD) [65] simulations. The activation energies needed for detrapping of D from the resulted irradiation-induced trap sites were determined with first-principles calculations using electron density functional theory (DFT) [64].…”

A brief summary of the progress on the EFDA tungsten materials program

“…The numerous material parameters for the RE were taken from the literature [38][39][40]. For validating the RE code, an exemplary system of 5, 15, and 30 keV deuterium (D) implantation into W was analyzed with the RE method and the results were compared with corresponding experimental results [41].…”