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Suzudo, Tomoaki; Yamaguchi, Masatake
no journal, ,
BCC transition metals are being discussed as candidates of structural materials in future nuclear systems, but their embrittlement at low temperatures is a concern. Besides, possibilities of so-called non-hardening embrittlement caused by grain boundary (GB) helium segregation have been pointed out. In the current study, we model GB helium segregation and following GB embrittlement based on the first principles calculations, and as an application of this modeling we numerically evaluate decrease in the GB strength of various BCC transition metals after they are exposed at the first wall of concept future nuclear fusion reactor, DEMO.
Yabuuchi, Kiyohiro*; Kimura, Akihiko*; Suzudo, Tomoaki
no journal, ,
Irradiation of high-energy particles into materials induces the formation of various lattice defects, which significantly influence their mechanical properties. Voids, which are aggregates of vacancies, are among such defects and become obstacles causing materials hardening. So far, we have been investigating obstacle strength factor of the facet voids created by ion-beam irradiation to pure Fe crystals. Because some ambiguity of the experimentally-measured factor was observed, we suspect that positional relation between interacting voids and dislocations influence the factor. The current study aimed at numerically investigating how this positional relation influences the factor by using molecular dynamics.
Yamaguchi, Masatake; Ebihara, Kenichi; Itakura, Mitsuhiro
no journal, ,
no abstracts in English
Okubo, Manabu*; Onitsuka, Takashi*; Fukumoto, Kenichi*; Suzudo, Tomoaki
no journal, ,
In structural materials of fast breeder and fusion rectors, vacancies produced by radiation displacements are clustered and form voids. Experimental evidence indicates that the voids become obstacles of dislocation motion and cause hardening of the materials, but the detailed mechanism of the hardening has not been clear. In the current study, we perform molecular dynamics simulation of the interaction between a screw dislocation and a void to clarify the radiation hardening mechanism. Our results clearly show that the screw dislocation is pinned between the center of the void and its rear interface.
Saito, Hiroyuki; Takagi, Shigeyuki*; Aoki, Katsutoshi*; Orimo, Shinichi*
no journal, ,
no abstracts in English