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Aghamiri, S. M. S.*; Sugawara, Naoya*; Ukai, Shigeharu; Ono, Naoko*; Sakamoto, Kan*; Yamashita, Shinichiro
Materials Characterization, 176, p.111043_1 - 111043_6, 2021/06
Advanced oxidation-resistant FeCrAl ODS alloys were developed via the control of composition-processing conditions for the accident tolerant fuel (ATF) cladding. For the first time, a single-crystal like recrystallized FeCrAl ODS alloy was achieved with a unique crystallographic texture of 110-plane and 211-direction and a high number density of fine nanoscale oxide particles. Evaluation of yield strengths at different temperatures showed higher values in transverse (T) direction than longitudinal (L) direction. The crystal orientation dependence of the yield strength up to 800C was attributed to lower value of Schmid factor in transverse direction. Accordingly, the critical resolved shear stress of this practical class of advanced materials was calculated in various temperatures.
Ukai, Shigeharu*; Ono, Naoko*; Otsuka, Satoshi
Comprehensive Nuclear Materials, 2nd Edition, Vol.3, p.255 - 292, 2020/08
Fe-Cr-based oxide dispersion strengthened (ODS) steels have a strong potential for high burnup (long-life) and high-temperature applications typical for SFR fuel cladding. Current progress in the development of Fe-Cr-based ODS steel claddings is reviewed, including their relevant mechanical properties, e.g. tensile and creep rupture strengths in the hoop directions. In addition, this paper reviewed the current research status on corrosion resistant Fe-Cr-Al-based ODS steel claddings, which are greatly paid attention recently as the accident tolerant fuel claddings for the light water reactor (LWR) and also as the claddings of the lead fast reactors (LFR) utilizing Pb-Bi eutectic (LBE) coolant.
Kumada, Takayuki; Oba, Yojiro; Motokawa, Ryuhei; Morooka, Satoshi; Tominaga, Aki; Tanida, Hajime; Shobu, Takahisa; Konno, Azusa; Owada, Kenji*; Ono, Naoko*; et al.
Journal of Nuclear Materials, 528, p.151890_1 - 151890_7, 2020/01
Times Cited Count:1 Percentile:12.16(Materials Science, Multidisciplinary)We have developed an anomalous small-angle X-ray scattering (ASAXS) diffractometer in SPring-8 to investigate irradiation-induced nanostructural change in ion-beam irradiated stainless steel. A thermally-aged MA956 stainless steel sample displays power-law scattering that follows the Porod law at the magnitude of scattering vector, Q, below 0.5 nm and an overlapped shoulder around 0.7 nm. After the ion-beam irradiation, the intensity of the shoulder remained unchanged, whereas that of the power-law scattering nearly doubled. This result indicates that none of the structural parameters of the Cr-rich nanoprecipitates, such as the number density, size, and interface roughness, were changed by the irradiation.
Aghamiri, S. M. S.*; Sowa, Takashi*; Ukai, Shigeharu*; Ono, Naoko*; Sakamoto, Kan*; Yamashita, Shinichiro
Materials Science & Engineering A, 771, p.138636_1 - 138636_12, 2020/01
Times Cited Count:32 Percentile:90.98(Nanoscience & Nanotechnology)Oxide dispersion strengthened (ODS) FeCrAl ferritic steels are being developed as potential accident tolerance fuel cladding materials for the light water reactors (LWRs) due to significant improvement in steam oxidation by alumina forming scale and good mechanical properties up to high temperatures. In this study, the microstructural characteristics and tensile properties of the two FeCrAl ODS cladding tubes with different extrusion temperatures of 1100C and 1150C were investigated during processing conditions. While the hot extruded sample showed micron sized elongated grains with strong -fiber in 110 texture, cold pilger rolling process change the microstructure to submicron/micron size grain structure along with texture evolution to both -fiber (110 texture) and -fiber ({111} texture) via crystalline rotations. Subsequently, final annealing resulted in evolution of microstructure to large grain recrystallized structure starting at recrystallization temperature of 810-850C. Two distinct texture development happened in recrystallized cladding tubes, i.e., only large elongated grains of (110) 211 texture following extrusion temperature of 1100C; and two texture components of (110) 211 and {111} 112 following higher extrusion temperature of 1150C. The different texture development and retarding of recrystallization progress in 1100C-extruded cladding tubes were attributed to higher distribution of oxide particles.
Konno, Azusa; Ono, Naoko*; Ukai, Shigeharu*; Kondo, Sosuke*; Hashitomi, Okinobu*; Kimura, Akihiko*
Materials Transactions, 60(11), p.2260 - 2266, 2019/11
Times Cited Count:1 Percentile:6.23(Materials Science, Multidisciplinary)A stability of cuboidal ' phase under heavy irradiation was studied for newly developed Ni-based Oxide Dispersion Strengthened (ODS) superalloy as a candidate for the core structural materials in VHTR or GFR. The ion irradiation was applied at 873K, 1073K, 1273K and the dose was 100 dpa. The ' phase remained the cuboidal shape at 873K but got out of the shape at 1073K after irradiation. Those growths can be explained by the Nelson-Hudson-Mazey (NHM) model. For the result of 1273K irradiation, however, huge ' phase appeared in the whole irradiated area at the post irradiation-observation. This behavior is interpreted in terms of disordering of the ordered ' phase due to cascade collision, and thus increasing Gibbs free energy of the disordered phase induces a change of the element distribution inside the irradiated area. The ordered ' phase was reproduced from the disordered state at the cooling after ion irradiation.
Yano, Yasuhide; Tanno, Takashi; Oka, Hiroshi; Otsuka, Satoshi; Inoue, Toshihiko; Kato, Shoichi; Furukawa, Tomohiro; Uwaba, Tomoyuki; Kaito, Takeji; Ukai, Shigeharu*; et al.
Journal of Nuclear Materials, 487, p.229 - 237, 2017/04
Times Cited Count:37 Percentile:96.77(Materials Science, Multidisciplinary)Ultra-high temperature ring tensile tests were carried out to investigate the tensile behavior of oxide dispersion strengthened (ODS) steel claddings and wrapper materials under severe accident conditions; temperatures ranged from room temperature to 1400C which is near the melting point of core materials. The experimental results showed that tensile strength of 9Cr-ODS steel claddings was highest in the core materials at the ultra-high temperatures between 900 and 1200C, but that there was significant degradation in tensile strength of 9Cr-ODS steel claddings above 1200C. This degradation was attributed to grain boundary sliding deformation with / transformation, which was associated with reduced ductility. On the other hand, tensile strength of recrystallized 12Cr-ODS and FeCrAl-ODS steel claddings retained its high value above 1200 C unlike the other tested materials. Present study includes the result of "R&D of ODS ferritic steel fuel cladding for maintaining fuel integrity at the high temperature accident condition" entrusted to Hokkaido University by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT).
Ijiri, Yuta*; Ono, Naoko*; Ukai, Shigeharu*; Yu, H.*; Otsuka, Satoshi; Abe, Yosuke; Matsukawa, Yoshitaka*
Philosophical Magazine, 97(13), p.1047 - 1056, 2017/02
Times Cited Count:2 Percentile:11.52(Materials Science, Multidisciplinary)The interaction between oxide particles and dislocations in a 9Cr-ODS ferritic steel is investigated by both static and in-situ TEM observation under dynamic straining conditions and room temperature. The measured obstacle strength () of the oxide particles was no greater than 0.80 and the average was 0.63. The dislocation loops around some coarsened particles were also observed. The calculated obstacle strength by a stress formula of the Orowan interaction is nearly equaled to the average experimental value. Not only cross-slip system but also the Orowan interaction should be considered as the main interaction mechanism between oxide particles and dislocation in 9Cr-ODS ferritic steel.
Abe, Yosuke; Tsuru, Tomohito; Shi, S.*; Ono, Naoko*; Ukai, Shigeharu*
Journal of Nuclear Science and Technology, 53(10), p.1528 - 1534, 2016/10
Times Cited Count:11 Percentile:71.62(Nuclear Science & Technology)Various types of nanometric defects such as voids and helium (He) bubbles produced by high energy neutron irradiations are known to degrade the mechanical properties of irradiated materials. In this study, we have evaluated the obstacle strength of He bubbles to the mobility of an edge dislocation in -iron for 2 and 4 nm bubbles with He-to-vacancy (He/V) ratios ranging from 0 to 1 at 300 and 500 K, by molecular dynamics simulation. Results showed that as the He/V ratio increases, the obstacle strength needed for the release of a dislocation from the bubble becomes stronger up to a moderate He/V ratio, and a further increase in the He/V ratio leads to weakening of the obstacle strength. For He/V = 1, the obstacle strengths are weaker than those at moderate He/V ratios depending on the bubble size and temperature. The extent of obstacle strength was found to be correlated with the dilation caused by He bubbles depending on the bubble size, He/V ratio, and temperature.
Tanaka, Shingo*; Yokota, Hideharu; Ono, Hirokazu; Nakayama, Masashi; Fujita, Tomoo; Takiya, Hiroaki*; Watanabe, Naoko*; Kozaki, Tamotsu*
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05
Takeda, Kiyoko*; Sato, Katsuya; Narumi, Issey*; Ono, Yutaka; Otsu, Naoko*; Yokoyama, Tadashi*
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 120, 2015/03
Shi, S.*; Ono, Naoko*; Ukai, Shigeharu*; Abe, Yosuke
Materials Science & Engineering A, 617, p.61 - 65, 2014/11
Times Cited Count:2 Percentile:12.26(Nanoscience & Nanotechnology)Bubble dispersion strengthened copper (BDS-Cu) was synthesized by using the pyrolysis gaseous products of Poly (methyl methacrylate) (PMMA) during spark plasma sintering (SPS) process. Bubbles with an average diameter of 14 nm are densely dispersed in copper matrix with a dispersion distance 119 nm. Vickers' hardness of BDS-Cu is 400 MPa higher than that of pure copper. The strengthening effect is due to the dislocation pinning effect of bubbles.
Asakura, Nobuyuki; Ashikawa, Naoko*; Ueda, Yoshio*; Ono, Noriyasu*; Tanabe, Tetsuo*; Nakano, Tomohide; Masuzaki, Suguru*; Itami, Kiyoshi; Kawano, Yasunori; Kawahata, Kazuo*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 87(7), p.485 - 486, 2011/07
no abstracts in English
Asakura, Nobuyuki; Nakano, Tomohide; Masuzaki, Takashi*; Ashikawa, Naoko*; Ueda, Yoshio*; Tanabe, Tetsuo*; Ono, Noriyasu*
Purazuma, Kaku Yugo Gakkai-Shi, 86(2), P. 124, 2010/02
no abstracts in English
Idomura, Yasuhiro; Yoshida, Maiko; Yagi, Masatoshi*; Tanaka, Kenji*; Hayashi, Nobuhiko; Sakamoto, Yoshiteru; Tamura, Naoki*; Oyama, Naoyuki; Urano, Hajime; Aiba, Nobuyuki; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 84(12), p.952 - 955, 2008/12
no abstracts in English
Masuzaki, Suguru*; Tokitani, Masayuki*; Miyamoto, Mitsutaka*; Nobuta, Yuji*; Ueda, Yoshio*; Ono, Noriyasu*; Sakamoto, Mizuki*; Ashikawa, Naoko*; Nakano, Tomohide; Itami, Kiyoshi
no journal, ,
A design of the movable material probe system for JT-60SA is proposed. The system provides the opportunity for inserting material specimens and diagnostics into the plasma vacuum vessel, and for specimens changing during experimental campaign. The system will consist of manipulator, gate-valves, working chamber and pumps. The system is under consideration to be installed in a bottom port. It will contribute to plasma-wall interaction studies in JT-60SA.
Sano, Keisuke*; Ono, Naoko*; Ukai, Shigeharu*; Hayashi, Shigenari*; Miura, Seiji*; Yamashita, Shinichiro; Inoue, Toshihiko
no journal, ,
no abstracts in English
Sano, Keisuke*; Ono, Naoko*; Ukai, Shigeharu*; Hayashi, Shigenari*; Miura, Seiji*; Yamashita, Shinichiro; Inoue, Toshihiko
no journal, ,
JAEA is study in the high Ni-alloy behavior as ODS substitute materials for the use in fast reactor. The precipitation behavior of double-prime (NiNb) in the high Ni steel was tested in prescription examinations. The results was the double-prime (NiNb) became a fault size and the hardness was decreased in the high prescription temperature and the long prescription time.
Takeda, Kiyoko*; Sato, Katsuya; Ono, Yutaka; Narumi, Issey*; Otsu, Naoko*; Yokoyama, Tadashi*
no journal, ,
no abstracts in English
Shi, S.*; Ono, Naoko*; Ukai, Shigeharu*; Hayashi, Shigenari*; Abe, Yosuke
no journal, ,
For the synthesis of a bubble dispersion strengthened copper by using the pyrolysis gaseous products of Poly (PMMA) during spark plasma sintering (SPS) process, a systematic investigation of the optimal conditions was performed. It was found that the optimal conditions are 5volPMMA for composition and maintaining temperature of 750C for 2 hours in SPS progress.
Shi, S.*; Ono, Naoko*; Ukai, Shigeharu*; Hayashi, Shigenari*; Togo, Koichi*; Fukumoto, Kenichi*; Abe, Yosuke
no journal, ,
Bubble dispersion strengthened (BDS) copper was synthesized by using the dissociated gases of the poly methyl methacrylate (PMMA) during Spark Plasma Sintering (SPS). By in-situ TEM observation under tensile loading, we analyzed a detachment angle of the dislocation from the bubble, and evaluated the pinning force of bubble for the moving dislocations. TEM observation showed homogeneously dispersed bubbles in Cu-5volPMMA and average bubble size was about 10 nm in diameter. It was analyzed that dispersed bubbles can strengthen copper with an angle 79 at dislocation detached from bubbles, which was consistent with the interaction angle 74 estimated by Vickers hardness measurement of the same specimen.