title: Detection of one-dimensional migration of single self-interstitial atoms in tungsten using high-voltage electron microscopy.
abstract: The dynamic behaviour of atomic-size disarrangements of atoms-point defects (self-interstitial atoms (SIAs) and vacancies)-often governs the macroscopic properties of crystalline materials. However, the dynamics of SIAs have not been fully uncovered because of their rapid migration. Using a combination of high-voltage transmission electron microscopy and exhaustive kinetic Monte Carlo simulations, we determine the dynamics of the rapidly migrating SIAs from the formation process of the nanoscale SIA clusters in tungsten as a typical body-centred cubic (BCC) structure metal under the constant-rate production of both types of point defects with high-energy electron irradiation, which must reflect the dynamics of individual SIAs. We reveal that the migration dimension of SIAs is not three-dimensional (3D) but one-dimensional (1D). This result overturns the long-standing and well-accepted view of SIAs in BCC metals and supports recent results obtained by ab-initio simulations. The SIA dynamics clarified here will be one of the key factors to accurately predict the lifetimes of nuclear fission and fusion materials.
authors.affiliation: Advanced Technology Research Laboratories, Nippon Steel &Sumitomo Metal Corporation, 1-8 Fuso-Cho, Amagasaki, Hyogo 660-0891, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Amino
authors.affiliation: Department of Materials Science, Faculty of Science and Engineering, Shimane University, 1060 Nishikawatsu, Matsue 690-8504, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Arakawa
authors.affiliation: Research Centre for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mori