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Wakai, Takashi; Abiko, Kenji*; Hishinuma, Akimichi*
no journal, ,
no abstracts in English
Ishijima, Yasuhiro; Kato, Chiaki; Yamamoto, Masahiro
no journal, ,
Zirconium has been utilized in chemical plant because of its superior corrosion resistance. But stress corrosion cracking (SCC) susceptibility and black oxide film growth had been reported under elastic stress condition. In order to clarify the SCC crack initiation and growth behavior of Zr in boiling nitric acid solution, constant load tests at potentiostatic condition were conducted. From the results, SCC crack generated from the oxide/metal interface into metal. This result suggests that the oxide generation induces tensile stress at the oxide/metal interface. And it is considered the stress acts as SCC crack generator.
Zr
)O
single crystal on its magnetic propertyKawamoto, Yasushi*; Hirao, Norie; Yamamoto, Hiroyuki; Baba, Yuji; Matsui, Toshiyuki*
no journal, ,
no abstracts in English
Mn)O
single crystal irradiated with swift heavy ionsShinoda, Ryoichi*; Ishikawa, Norito; Hirao, Norie; Yamamoto, Hiroyuki; Baba, Yuji; Matsui, Toshiyuki*; Iwase, Akihiro*
no journal, ,
no abstracts in English
Tode, Mayumi; Harries, J.; Teraoka, Yuden; Yoshigoe, Akitaka
no journal, ,
In order to study the relationships between the thermal degeneration of oxide layer on hydrogen storage materials and the thermal desorption of hydrogen, thermal desorption spectroscopy (TDS) of an artificial oxide layer and synchrotron radiation X-ray photoelectron spectroscopy (SR-XPS) were measured at the same time. All experiments have been conducted at the surface chemistry experimental station (SUREAC2000) at BL23SU, SPring-8. After the surface of V had been cleaned, an artificial oxide layer was formed with a supersonic oxygen molecular beam. And, the deuterium ion was implanted. The O-1s peak has decreased at about 473 K, the oxide layer was resolved. The desorption of deuterium ion was observed at about 450 K.
Maekawa, Masaki; Yabuuchi, Atsushi; Kawasuso, Atsuo; Aihara, Jun; Sawa, Kazuhiro
no journal, ,
no abstracts in English
Ti at high pressure and high temperatureSaito, Hiroyuki; Machida, Akihiko; Katayama, Yoshinori; Aoki, Katsutoshi
no journal, ,
no abstracts in English
Higuchi, Kensuke; Machida, Akihiko; Katayama, Yoshinori; Sakaki, Koji*; Nakamura, Yumiko*
no journal, ,
no abstracts in English
Abe, Yosuke; Jitsukawa, Shiro
no journal, ,
We investigated effects of the mobility of SIA clusters on the microstructural evolution under cascade irradiation conditions in austenitic stainless steel using the cluster dynamics simulation code extended in this study. It was shown that taking into account the mobility of relatively small SIA clusters can significantly improve the accuracy of predicting the irradiation dose and temperature dependences of the number density and size of SIA clusters.
Tsuru, Tomohito
no journal, ,
The dislocation-grain-boundary process is fundamental to the improvement of the mechanical properties of metallic materials. This process contributes significantly to plastic deformation as well as dislocation-dislocation interactions. These lattice defects have been effectively utilized for material strengthening as determined by the Hall-Petch relationship. However, it becomes well-known that the individual defect structure plays a great role in the whole materials system. In this study, we have developed nano-mesoscale simulation methods to understand defects dynamics under deformation since these materials characteristics are derived from mesoscopic behavior.
Yabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo
no journal, ,
It is said that vacancies play an important role in high-temperature water stress corrosion cracking. In the crack tip on which the tensile stress has concentrated, there is a possibility that the vacancy diffusion behavior is different. In the present study, the recovery behavior under the tensile stress of the irradiation-induced vacancies in Type 304 stainless steels was observed. 2 MeV electrons were irradiated at 60
C to the notched Type 304 stainless steel test pieces. Annealing-treatment was performed with the tensile force added to the test piece, and around the notch tip region was observed by using a positron microbeam. As a result, high positron annihilation 
rays peak intensity region was observed from the notch tip to the range of about 1 mm. This may imply that the vacancy-type defects were accumulated by the annealing under the stress gradient.
Kamakura, Nozomu; Takeda, Yukiharu; Saito, Yuji; Yamagami, Hiroshi; Tsubota, Masami*; Paik, B.*; Ichikawa, Takayuki*; Kojima, Yoshitsugu*; Muro, Takayuki*; Kinoshita, Toyohiko*
no journal, ,
Lithium amide (LiNH
) is lightweight complex hydride expected as a high-capacity hydrogen storage material. The electronic structure of lithium amide (LiNH) is investigated by soft X-ray emission spectroscopy (XES) and absorption spectroscopy (XAS). The unoccupied and occupied parts of the N 2
partial density of states are studied by N 1
XAS in the fluorescence yield mode and XES using soft X-ray (h
=425eV) of SPring-8. The XES and XAS spectra show a band gap between the valence and conduction bands. The valence band in the XES spectrum consists of three peaks, which extend up to 
-8eV from the valence band top. The overall feature of the electronic structure of lithium amide by the XES and XAS is consistent with the band calculation. The strongly hybridized state with H 1 observed on the high binding energy side in the XES is discussed.
Takeuchi, Tomoaki; Nishiyama, Yutaka; Katsuyama, Jinya; Onizawa, Kunio; Matsukawa, Yoshitaka*; Toyama, Takeshi*; Nagai, Yasuyoshi*; Kameda, Jun*
no journal, ,
Microstructure evolution on stainless overlay cladding of reactor pressure vessel was quantitatively investigated by means of three-dimensional local electrode atom probe (3DAP) in nano-scale. The cladding material was neutron-irradiated up to 7
10
n/cm
(E 
1 MeV)at JMTR. In ferrite phases of cladding material, a 12% of Cr concentration fluctuation, which was arisen through a spinodal decomposition, observed before the irradiation was progressed to 20% after the irradiation while the wave length of the fluctuation was almost not changed about 8-10 nm before and after the irradiation. In addition, Ni, Si and Mn concentration fluctuations were also observed. Correlation between Cr concentration fluctuation and hardness, other elements concentration fluctuation and differences from the thermal aging will be reported in presentation.