Hydrogen embrittlement and its prevention in 7XXX aluminum alloys with high Zn concentrations

Shimizu, Kazuyuki*; Toda, Hiroyuki*; Fujihara, Hiro*; Yamaguchi, Masatake; Uesugi, Masayuki*; Takeuchi, Akihisa*; Nishijima, Masahiko*; Kamada, Yasuhiro*

Corrosion, 79(8), p.818 - 830, 2023/08

https://doi.org/10.5006/4300

7xxx aluminum alloys are representative high-strength aluminum alloys; however, mechanical property degradation due to hydrogen hinders further strengthening. We propose the dispersion of Mn-based second-phase particles as a novel technique for preventing 7xxx aluminum alloy hydrogen embrittlement. In this study, the deformation and fracture behaviors of high hydrogen 7xxx alloys containing 0.0% Mn and 0.6% Mn are observed in situ using synchrotron radiation X-ray tomography. The obtained macroscopic hydrogen embrittlement is quantitatively analyzed based on hydrogen partitioning in alloys. Adding 0.6% Mn, generating second-phase particles with high hydrogen trapping abilities, significantly suppresses hydrogen-induced quasicleavage fracture.

Conceptual design and related R&D on ITER mechanical based primary pumping system

Tanzawa, Sadamitsu; Hiroki, Seiji; Abe, Tetsuya; Shimizu, Katsusuke*; Inoue, Masahiko*; Watanabe, Mitsunori*; Iguchi, Masashi*; Sugimoto, Tomoko*; Inohara, Takashi*; Nakamura, Junichi*

JAEA-Technology 2008-076, 99 Pages, 2008/12

JAEA-Technology-2008-076.pdf:35.19MB

The primary vacuum pumping system of the International Thermonuclear Experimental Reactor (ITER) exhausts a helium (He) ash resulting from the DT-burn with excess DT fueling gas, as well as performing a variety of functions such as pump-down, leak testing and wall conditioning. A mechanical based vacuum pumping system has some merits of a continuous pumping, a much lower tritium inventory, a lower operational cost and easy maintenance, comparing with a cryopump system, although demerits of an indispensable magnetic shield and insufficient performance for hydrogen (H) pumping are well recognized. To overcome the demerits, we newly fabricated and tested a helical grooved pump (HGP) unit suitable for H pumping at the ITER divertor pressure of 0.1-10 Pa. Through this R&D, we successfully established many design and manufacturing databases of large HGP units for the lightweight gas pumping. Based on the databases, we conceptually designed the ITER vacuum pumping system mainly comprising the HGP with an optimal pump unit layout and a magnetic shield. We also designed conceptually the reduced cost (RC)-ITER pumping system, where a compound molecular pump combining turbine bladed rotors and helical grooved ones was mainly used. The ITER mechanical based primary pumping system proposed has eventually been a back-up solution, whereas a cryopump based one was formally selected to the ITER for construction.

Development of a compact W-shaped pumped divertor in JT-60U

Sakurai, Shinji; Hosogane, Nobuyuki; Masaki, Kei; ; ; *; *; Shimizu, Katsuhiro; Akino, Noboru; Miyo, Yasuhiko; et al.

Fusion Engineering and Design, 39-40, p.371 - 376, 1998/00

https://doi.org/10.1016/S0920-3796(97)00176-2

no abstracts in English

Stress-induced premature senescence in a human glioma cell line after irradiation with heavy ion beam

Oue, Atsushi*; Shimizu, Nobuaki*; Tanaka, Atsushi*; Otsuki, Takahiro*; Shinagawa, Masahiko*; Mori, Takahisa*; Saha, M. N.*; Ariful, H. S.*; Islam, S.*; Nakamura, Takako*; et al.

no journal, , 

no abstracts in English

Temperature dependence of polarization domains in PMN-28% PT relaxor ferroelectric observed by the coherent soft X-ray speckle patterns

Ishino, Masahiko; Namikawa, Kazumichi; Matsushita, Mitsuyoshi*; Owada, Kenji; Shimizu, Daisuke*; Sakamoto, Junya*; Mizuki, Junichiro

no journal, , 

no abstracts in English