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

H Wang and K Xu and D Wang and N Gao and YH Li and S Jin and XL Shu and LY Liang and GH Lu, SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY, 64, 257012 (2021).

DOI: 10.1007/s11433-020-1676-y

We investigate the interaction between <111> self-interstitial atoms (SIAs) and 1/2<111> 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 1/2111 loop and the nonequivalent configurations of <111> 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 1/2111 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 <111> 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.

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