Migration and nucleation of helium atoms at (110) twist grain boundaries in tungsten
YX Feng and JX Shang and GH Lu, JOURNAL OF NUCLEAR MATERIALS, 487, 200-209 (2017).
The migration and nucleation of He atoms at three typical (110) twist grain boundaries (TGBs): the low-angle grain boundary (LAGB), the ordinary high-angle grain boundary (HAGB) and the Sigma 3 TGB in W are investigated using molecular dynamics simulations. The presence of TGBs can absorb He atoms from bulk and impede the growth of He bubbles. Moreover, different grain boundary (GB) structures behave differently when interacting with He atoms. The LAGB can control the He distribution on the GB plane through its screw dislocation network, suggesting a promising approach for design of radiation tolerant materials. The ordinary HAGB presents a strong trap effect due to its disordered GB structure, which may induce a large He retention at the GB and embrittlement. The Sigma 3 TGB can provide a diffusion path for He atoms, although the diffusion rate is not as fast as it in bulk. (C) 2017 Elsevier B.V. All rights reserved.
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