Anisotropic interaction between self-interstitial atoms and 1/2<111> dislocation loops in tungsten

Abstract

We investigate the interaction between self-interstitial atoms (SIAs) and 1/2 self-interstitial dislocation loops in tungsten (W) via atomistic simulations. We explore the variation of the anisotropic distribution of binding energies with the shapes and sizes of the 1/2[111] loop and the nonequivalent configurations of SIAs. For an arbitrarily shaped loop, SIA can be more easily trapped in the concave region of the loop than the convex region, which forms a loop whose curvature is closer to that of a circular loop. The direction of SIAs can largely affect the interaction behaviors with the loop. The capture distance of an SIA by the edge of a circular-shaped 1/2[111] loop is clearly elongated along the direction of the SIA; however, it weakly depends on the size of the loop. Then, we analyze the slanted ring-like capture volume of SIAs formed by the circular loop based on their generated anisotropic stress fields. Furthermore, the binding energies obtained from the elastic theory and atomistic simulations are compared. The results provide a reasonable interpretation of the growth mechanism of the loop and the anisotropic interaction that induces irregular-shaped capture volume, affording an insight into the numerical and Object Kinetic Monte Carlo simulations to evaluate the long-term and large-scale microstructural evolution and mechanical properties of W.