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Nucleation and growth of helium bubble at (110) twist grain boundaries in tungsten studied by molecular dynamics*

Authors :
Ning Gao
Shangquan Zhao
Ning Li
Guang Ran
Fang-Biao Li
Source :
Chinese Physics B. 28:085203
Publication Year :
2019
Publisher :
IOP Publishing, 2019.

Abstract

Migration of He atoms and growth of He bubbles in high angle twist grain boundaries (HAGBs) in tungsten (W) are investigated by atomic simulation method. The energy and free volume (FV) of grain boundary (GB) are affected by the density and structure of dislocation patterns in GB. The migration energy of the He atom between the neighboring trapping sites depends on free volume along the migration path at grain boundary. The region of grain boundary around the He bubble forms an ordered crystal structure when He bubble grows at certain grain boundaries. The He atoms aggregate on the grain boundary plane to form a plate-shape configuration. Furthermore, high grain boundary energy (GBE) results in a large volume of He bubble. Thus, the nucleation and growth of He bubbles in twist grain boundaries depend on the energy of grain boundary, the dislocation patterns and the free volume related migration path on the grain boundary plane.

Details

ISSN :
16741056
Volume :
28
Database :
OpenAIRE
Journal :
Chinese Physics B
Accession number :
edsair.doi...........5455f3ca4e8ab101cec25954868c4364
Full Text :
https://doi.org/10.1088/1674-1056/28/8/085203