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Wakui, Takashi; Saito, Shigeru; Futakawa, Masatoshi
Jikken Rikigaku, 24(4), p.212 - 218, 2024/12
Irradiation damage is one of the main factors determining the lifetime of the mercury target vessel for spallation neutron source in J-PARC. To understand material degradation of the used vessels, it is planned to conduct an evaluation using inverse analyses with indentation tests on the structural materials of the used vessels and numerical experiments. This evaluation technique was applied to two kinds of ion-irradiated materials with different displacement damage doses, in which the irradiation condition was simulated. It could be confirmed that the ultimate strength increased, and the total elongation decreased with increasing irradiation. These trends are like the material degradation behaviors which have been reported by using small specimen's tensile tests.
Wakui, Takashi; Saito, Shigeru; Futakawa, Masatoshi
Materials, 17(23), p.5925_1 - 5925_14, 2024/12
Times Cited Count：0 Percentile：0.00(Chemistry, Physical)The ductile properties of irradiated materials are one of the important indicators related to their structural integrity. Indentation tests are used for evaluating the ductile properties easily and rapidly. Constants in the material constitutive equation were identified via inverse analysis using the Kalman filter, such that the numerical experimental results reproduced the indentation test results. Numerical tensile experiments were conducted using stress-strain curves with the identified constants to obtain nominal stress-strain curves. Furthermore, two methods were proposed for evaluating the total elongation. Evaluated minimum total elongation was 10 %. The evaluation results of ion-irradiated materials were similar to the tensile test results of irradiated materials.
compoundsFrazer, D.*; Saleh, T. A.*; Matsumoto, Taku; Hirooka, Shun; Kato, Masato; McClellan, K.*; White, J. T.*
Nuclear Engineering and Design, 423, p.113136_1 - 113136_7, 2024/07
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Nanoindentation based techniques can be employed on minute volumes of material to measure mechanical properties, including Young's modulus, hardness, and creep stress exponents. In this study, (U,Ce)O solid solutions samples are used to develop elevated temperature nanoindentation and nanoindentation creep testing methods for use on mixed oxide fuels. Nanoindentation testing was performed on 3 separate (Ux-1,Cex)O compounds ranging from x equals 0.1 to 0.3 at up to 800 
C: their Young's modulus, hardness, and creep stress exponents were evaluated. The Young's modulus decreases in the expected linear manner while the hardness decreases in the expected exponential manner. The nanoindentation creep experiments at 800 C give stress exponent values, n=4.7-6.9, that suggests dislocation motion as the deformation mechanism.
synchrotron X-ray scattering and nanoindentation testIm, S.*; Jee, H.*; Suh, H.*; Kanematsu, Manabu*; Morooka, Satoshi; Choe, H.*; Nishio, Yuhei*; Machida, Akihiko*; Kim, J.*; Lim, S.*; et al.
Construction and Building Materials, 365, p.130034_1 - 130034_18, 2023/02
Times Cited Count：17 Percentile：77.68(Construction & Building Technology)Kakiuchi, Kazuo; Yamauchi, Akihiro*; Amaya, Masaki; Udagawa, Yutaka; Kitano, Koji*
Proceedings of TopFuel 2022 (Internet), p.409 - 418, 2022/10
Wang, Y.*; Tomota, Yo*; Omura, Takahito*; Gong, W.*; Harjo, S.; Tanaka, Masahiko*
Acta Materialia, 196, p.565 - 575, 2020/09
Times Cited Count：42 Percentile：89.76(Materials Science, Multidisciplinary)Sun, Y.*; Abe, Yuta; Muta, Hiroaki*; Oishi, Yuji*
Journal of Nuclear Science and Technology, 57(8), p.917 - 925, 2020/08
Times Cited Count：5 Percentile：42.20(Nuclear Science & Technology)Motohashi, Yoshinobu*; Shibata, Taiju; Harjo, S.*; Sakuma, Takaaki*; Ishihara, Masahiro; Baba, Shinichi; Sawa, Kazuhiro
Proceedings of 14th International Federation for Heat Treatment and Surface Engineering Congress Transactions of Materials and Heat Treatment Vol.25 No.5, p.1032 - 1036, 2004/10
no abstracts in English
ionsLee, C. G.; Omura, Takahito*; Takeda, Yoshihiko*; Matsuoka, Saburo*; Kishimoto, Naoki*
Journal of Nuclear Materials, 326(2-3), p.211 - 216, 2004/03
Times Cited Count：4 Percentile：28.64(Materials Science, Multidisciplinary)Magnesium aluminate spinel of single crystal was irradiated with 60 keV Cu at a dose rate up to 100 
A/cm
, to a total dose of 3
10
ions/cm, in order to study changes in hardness and step-height swelling by high-flux implantation. Hardness determined by nano-indentation measurements steeply decreased with implantation. There is a strong negative correlation between dose-rate dependences of the hardness and the step-height swelling: the former decreases as the latter increases. The Rutherford Backscattering Spectrometry (RBS)/channeling measurements showed that the spinel is not completely amorphized over the dose-rate range in this study, and the radiation-induced softening observed is not due to amorphization. Results of optical absorbance suggested that radiation-induced point defects and their clusters on the anion sublattices of the spinel played an important role in the radiation-induced swelling under high-flux ion implantation.
Futakawa, Masatoshi; Kurata, Yuji; Henry, J.*; Ioka, Ikuo; Saito, Shigeru; Naito, Akira
FZKA-6876, p.166 - 171, 2003/12
A report at MEGAPIE(Megawatt Pilot Experiment) Technical R & D Meeting is collected into an FZK report. Triple ion beam irradiation tests on T91 specimens were conducted under MEGAPIE condition using TIARA facility at JAERI. Results of triple ion beam irradiation up to 15dpa, 1400appm He, 10000appm H at 320C were compared with those of single or dual beam irradiation of Fe or He ions by use of a micro-indentation method. Hardsness increase was mainly attributed to displacement damage by Fe ions. A little effect on hardness was found on simultaneous implantation of He and H ions. An analysis method to predict mechanical characterization form micro-indentation test results was developed on ion irradiated materials.
Wakui, Takashi*; Futakawa, Masatoshi; Tanabe, Yuji*; Ioka, Ikuo
Zairyo, 51(6), p.681 - 687, 2002/06
This paper describes the novel technique for determining constants in constitutive equaution of elastic-palstic materials by the indentation test with indenters having different tip angles. FEM analyses were carried out to evaluate the effect of material constants and the indenter tip angle on the load-depth curve. The constitutive equation was determeined from the characterized curves associated with the effects on the slope. Simiulation analyses were performed for some material models to exammine accuracy of the presented technique. It is confirmed that this technique is useful to determine the constitutive equation of sub-surface of materials or coatings.
Futakawa, Masatoshi; Wakui, Takashi*; Tanabe, Yuji*; Ioka, Ikuo
Journal of Materials Research, 16(8), p.2283 - 2292, 2001/08
no abstracts in English
Shibata, Taiju; Ishihara, Masahiro; Takahashi, Tsuneo*; Motohashi, Yoshinobu*; Hayashi, Kimio
JAERI-Research 2001-024, 24 Pages, 2001/03
JAERI-Research-2001-024.pdf:6.25MB
no abstracts in English
Shibata, Taiju; Ishihara, Masahiro; Takahashi, Tsuneo*; Motohashi, Yoshinobu*
Proceedings of Asian Pacific Conference on Fracture and Strength '01(APCFS '01) and International Conference on Advanced Technology in Experimental Mechanics '01 (ATEM '01), p.894 - 898, 2001/00
no abstracts in English
Ishihara, Masahiro; Baba, Shinichi; Aihara, Jun; Hayashi, Kimio; Arai, Taketoshi; Ishino, Shiori*
Proceedings of 1st Information Exchange Meeting on Basic Studies on High-Temperature Engineering, p.299 - 308, 1999/09
no abstracts in English
Futakawa, Masatoshi; Steinbrech, R. W.*; Wakui, Takashi*;
Hyomen Gijutsu, 50(1), p.58 - 62, 1999/00
no abstracts in English
Kanari, Moriyasu*; ; ; Eto, Motokuni
Carbon, 35(10-11), p.1429 - 1437, 1997/00
Times Cited Count：39 Percentile：81.00(Chemistry, Physical)no abstracts in English
Ishihara, Masahiro; Aihara, Jun; Oku, Tatsuo*
Proc. of 14th Int. Conf. on Structural Mechanics in Reactor Technology, 2, p.455 - 462, 1997/00
no abstracts in English
Ishihara, Masahiro; Oku, Tatsuo*
Nihon Kikai Gakkai Rombunshu, A, 62(602), p.2305 - 2309, 1996/00
no abstracts in English
Sakai, Tomoki*; Wakui, Takashi; Saito, Shigeru; Futakawa, Masatoshi; Mori, Kotaro*
no journal, ,
One of dominant factors to determine the lifetime of components used under the high-radiation environment is the radiation damage of materials and then understanding of the radiation damage is very important. Although ion irradiation has been conducted as the method simulating the radiation damage, the damaged area is limited to the surface layer of the specimen and has the gradient damage distribution. Micro-indentation tests with a Berkovich indenter were conducted in irradiated and unirradiated area on ion irradiated specimens and the micro-hardness was estimated from load and depth curve. The micro-hardness increased by the irradiation. The micro-hardness increased further under the irradiation condition that hydrogen ion and helium ion were added. On the other hand, the micro-hardness decreased with increasing irradiated temperature.
Sakai, Tomoki*; Wakui, Takashi; Saito, Shigeru; Futakawa, Masatoshi; Mori, Kotaro*
no journal, ,
Radiation damage to materials is a factor that determines the lifetime of equipment used in high-radiation environments, and it is essential to understand the radiation damage. Ion irradiation has been used as a method of simulating irradiation damage, but the damage area is limited to the thin surface layer and has a gradient damage distribution. Therefore, micro-indentation test was applied as the method to investigating the mechanical properties and then the hardness in irradiated and unirradiated area. Increase of hardness due to irradiation was confirmed and the hardness increased by adding light ion. On the other hand, amount of increase in hardness decreased with increasing the irradiation temperature.
