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Yamaguchi, Masatake
Materia, 62(10), p.646 - 651, 2023/10
The tendency of solid metal in contact with a liquid metal to undergo brittle fracture is called liquid metal embrittlement. The degree of embrittlement varies depending on the liquid-solid metal combination, called the element selectivity (specificity) of liquid metal embrittlement. We have added further explanations to a published paper that discusses the energetics of embrittlement-prone combinations and possible embrittling mechanisms based on energetic considerations from first-principles calculations.
Kobayashi, Keita; Nakamura, Hiroki; Itakura, Mitsuhiro; Machida, Masahiko; Okumura, Masahiko
Materia, 62(3), p.175 - 181, 2023/03
no abstracts in English
Yoshida, Kenta*; Toyama, Takeshi*; Inoue, Koji*; Nagai, Yasuyoshi*; Shimodaira, Masaki
Materia, 62(3), p.154 - 158, 2023/03
no abstracts in English
Hojo, Tomohiko*; Shibayama, Yuki; Ajita, Saya*; Koyama, Motomichi*; Akiyama, Eiji*
Materia, 61(7), p.413 - 418, 2022/07
no abstracts in English
Tsuru, Tomohito
Materia, 60(1), p.25 - 29, 2021/01
The plastic deformation is determined by the average collective motion of dislocations. The subsequent interaction between dislocations in different slip planes contributes to the hardening process. In this paper, I develop parallelized molecular dynamics and visualization codes to simulate three-dimensional polycrystalline models including intergranular dislocation sources and explore a mechanism of T-C asymmetry for UFG metals. In addition, we performed the first-principles calculations of the dislocation core and examined the interaction energy between a screw dislocation and solute and the change in energy barrier for dislocation motion, where a quadrupolar configuration was used to evaluate the effects of solute on dislocation motion.
Yoneda, Yasuhiro; Yoshigoe, Akitaka; Takeda, Yukiharu; Shiwaku, Hideaki; Matsumura, Daiju; Shobu, Takahisa; Tamura, Kazuhisa
Materia, 58(12), p.763 - 769, 2019/12
This is an introduction to the equipment provided for each implementation period belonging to the structure analysis platform in the nanotechnology platform.
Inoue, Toshihiko; Sekio, Yoshihiro; Watanabe, Hideo*
Materia, 58(2), P. 92, 2019/02
For the evaluation of irradiated segregation behavior, Austenite-based stainless steel for the fast reactor, during irradiation was evaluated by utilizing TIARA facility (Irradiate temperature: 600 
C, Dose: 100 dpa) was observed by analytical electron microscope (JEM-ARM20FC). As a result of observation, the large-size void is observed in irradiation area, and MX segregation (containing Niobium) is not observed. In un-irradiation area the MX segregation is observed. And it is observed conspicuously that Nickel is segregation on the void surface. By the latest high-performance TEM utilization, these phenomenon are able to visualize. It is expected for the clarification of the irradiation damage and mechanism of void swelling, by the analyzing these phenomenon utilization with the latest high-performance TEM utilization.
Ebihara, Kenichi
Materia, 57(7), p.338 - 344, 2018/07
no abstracts in English
Yamaguchi, Masatake
Materia, 56(8), p.480 - 483, 2017/08
no abstracts in English
Tsuru, Tomohito
Materia, 56(1), p.5 - 13, 2017/01
Elements strategy becomes important to investigate alternative materials of rare metals. We have dedicated to establish a new approach based on computational methods. In the present paper, we propose two approaches based on first-principles and theory of dislocations. These methods are introduced to magnesium alloys.
Yamaguchi, Masatake
Materia, 54(3), p.110 - 117, 2015/03
no abstracts in English
Endo, Naruki; Saito, Hiroyuki; Machida, Akihiko; Katayama, Yoshinori
Materia, 53(3), p.94 - 99, 2014/03
no abstracts in English
Yoshiie, Toshimasa*; Futakawa, Masatoshi; Naoe, Takashi; Komatsu, Masao*; Sato, Koichi*; Xu, Q.*; Kawai, Masayoshi*
Materia, 52(8), p.390 - 394, 2013/08
In the liquid mercury target for the spallation neutron source, pressure waves occurs owing to the high-intense proton beam bombardment. The pressure waves induces the cavitation in the interface between the mercury and the target vessel through the propagation process. Erosion damage composed of micro-pits clusters is formed by the micro-jets and shock waves emitted from cavitation bubble collapse. In this paper, researches for damage structure of the material that was examined using the electroMagnetic IMpact Testing Machine (MIMTM) form the viewpoint of high-speed deformation. The result showed that the 200
300 m/s of collision velocity for micro-jet impacting which was estimated from the numerical simulation is reasonable value.
Machida, Akihiko; Saito, Hiroyuki; Matsumura, Daiju; Takeda, Yukiharu
Materia, 52(7), p.337 - 341, 2013/07
We have investigated the structural and electronic properties of the hydrides or hydrogen storage materials focusing on the hydrogen-metal interactions using synchrotron radiation X-rays. X-rays interact with electrons of atoms in materials, hence, we can use X-rays as one of the powerful probes for investigating the chemical bonding states. The hydrogen-metal interactions give us the important knowledge to develop the high performance hydrogen storage materials. In this paper, we present the recent results of our studies for the hydrogen storage materials. By using our measurement apparatuses and also using our developed techniques, we obtained the new knowledge of structural and electronic properties of hydrides and hydrogen storage materials.
Ioka, Ikuo; Kiuchi, Kiyoshi; Nakayama, Jumpei*
Materia, 49(3), p.122 - 124, 2010/03
In reprocessing plants, it is known that the corrosion environment for structural materials is extremely severe to be used boiling nitric acid with oxidized ions related to fission products (FP). Ultra low carbon stainless steels (SUS304ULC) were developed from the experience of corrosion troubles in foreign plants and the operation of domestic plant. In an advanced reprocessing plant, it is predicted that the corrosion environment will be more severe because of the advanced spent fuels which contain much FP than an existing spent fuel. Therefore, it is necessary to develop the new stainless steel with excellent corrosion resistance in comparison with SUS304ULC. We developed an extra high purity stainless steel (EHP alloy) having superior corrosion resistance in the strong acid environment for the advanced reprocessing plant. In the production process of EHP alloy, the practical use was taken into consideration. This report introduces the present conditions of EHP alloy.
Yamashita, Shinichiro; Sekine, Manabu*; Akasaka, Naoaki
Materia, 47(12), P. 624, 2008/12
no abstracts in English
Yano, Yasuhide; Yamashita, Shinichiro; Yoshitake, Tsunemitsu; Akasaka, Naoaki; Takahashi, Heishichiro
Materia, 47(12), P. 625, 2008/12
no abstracts in English
Kikuchi, Kenji; Hamaguchi, Dai; Saito, Shigeru
Materia, 47(12), P. 635, 2008/12
TEM observation on austenitic stainless steel irradiated by proton beam was reported. Two cases were studied; those are 10 dpa, 623 K and 800 appm, and 20 dpa. 693 K and 1800 appm in irradiation damage, irradiated temperature and Helium gas production, respectively. The results showed that bubbles are formed homogeneously in the matrix and the bubble size is averagely 2.5 nm. Swelling volume is calculated to be less than 0.1% by the bubbles size and the bubble density.
Nogiwa, Kimihiro; Nishimura, Akihiko; Oba, Hironori; Yokoyama, Atsushi; Okubo, Tadakatsu*; Hono, Kazuhiro*
Materia, 47(12), P. 626, 2008/12
no abstracts in English
Shibayama, Tamaki*; Kishimoto, Hirotatsu*; Koyama, Akira*; Yano, Yasuhide
Materia, 47(12), P. 628, 2008/12
no abstracts in English
