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Ando, Masami; Wakai, Eiichi; Sawai, Tomotsugu; Tanigawa, Hiroyasu; Furuya, Kazuyuki; Jitsukawa, Shiro; Takeuchi, Hiroshi; Oka, Keiichiro*; Onuki, Somei*; Koyama, Akira*
Journal of Nuclear Materials, 329-333(2), p.1137 - 1141, 2004/08
Times Cited Count：50 Percentile：93.75(Materials Science, Multidisciplinary)One of the most crucial issues on R&D of reduced activation ferritic/martensitic steels is the effect of helium on the degradation of fracture toughness. The synergistic effects of displacement damage and helium on F82H steel can be partially simulated by martensitic steels doped with 
B or 
Ni in a mixed spectrum fission reactor. However, the control of helium production rate is difficult and the chemical effects of B or Ni doping on mechanical property are not small. Therefore, multi-ion irradiation method is the most convenient and accurate method to simulate various irradiation conditions. Moreover, the effects of helium on irradiation hardening behavior can be examined by combining ion-irradiation with ultra micro-indentation technique. The purpose of this study is to examine the extra component of radiation hardening due to implanted helium in F82H. The extra component of irradiation hardening due to helium was hardly detected in the dual-beam irradiation. Therefore, the effect on irradiation hardening below 630K of helium (
500 appm) was very small.
Hirose, Takanori; Shiba, Kiyoyuki; Sawai, Tomotsugu; Jitsukawa, Shiro; Akiba, Masato
Journal of Nuclear Materials, 329-333(Part1), p.324 - 327, 2004/08
Times Cited Count：55 Percentile：94.79(Materials Science, Multidisciplinary)Reduced activation ferritic/martensitic steel, RAFs is the leading candidates for the structural materials of breeding blankets. HIP is examined as a near-net-shape fabrication process for this structure. The HIP requires heating above the normalizing temperature and the final microstructural features depends on the HIP processing conditions. Conventional HIP process caused a prior-austenite grain (PAG) coarsening of RAFs and subsequent increase of ductile brittle transition temperature. Japanese RAFs F82H and its modified steels were investigated by metallurgical method after isochronal heat treatment up to 1473K simulating HIP equivalent thermal hysteresis. Although Conventional F82H IEA heat showed significant grain growth after conventional solid HIP conditions (1313K 
2hr.), F82H with 0.1wt.% tantalum kept fine grain after the same heat treatment. On the other hands, conventional RAF/Ms with coarse grain were recovered by the post HIP normalizing at temperature below TaC dissolution temperature. This process can refine the PAG size of F82H more than ASTM grain size number 7.
Tanigawa, Hiroyasu; Hashimoto, Naoyuki*; Sokolov, M. A.*; Klueh, R. L.*; Ando, Masami
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.58 - 60, 2004/04
1TCT fracture toughness specimens of F82H-IEA steel were fatigue precracked and sliced in specimen thickness wise for microstructure analysis around the precrack. The microstructure around the precrack was observed by optical microscopy (OM), scanning electron microscopy (SEM), orientation imaging microscopy (OIM), and transmission electron microscopy (TEM). TEM samples around the crack front were prepared by focused ion beam (FIB) processor. The fracture surfaces of tested 1TCT specimens were also observed. OM observation showed that the precrack penetration was straight in the beginning, and then tended to follow a prior austenite grain boundary and to branch into 2 to 3 directions at the terminal. SEM and OIM observations revealed that the both microstructures around the precracks and ahead of the precrack had turned into cell structure, which is the typical microstructure of fatigue-loaded F82H. TEM images and inverse pole figures obtained from the crack-front region confirmed this structure change.
phaseSawai, Tomotsugu; Tabuchi, Masayuki*; Wakai, Eiichi; Hishinuma, Akimichi
Proceedings of Materials Research Society Symposium, Vol.650, p.R3.9.1 - R3.9.6, 2001/00
no abstracts in English
Sawai, Tomotsugu; Shiba, Kiyoyuki; Hishinuma, Akimichi
Journal of Nuclear Materials, 283-287(Part.1), p.657 - 661, 2000/12
Times Cited Count：43 Percentile：90.73(Materials Science, Multidisciplinary)no abstracts in English
Sasajima, Hideo; Fuketa, Toyoshi; Nakamura, Takehiko; Nakamura, Jinichi; Uetsuka, Hiroshi; Kikuchi, Keiichi*; Abe, Tomoyuki*
JAERI-Research 99-060, p.62 - 0, 2000/03
JAERI-Research-99-060.pdf:12.05MB
no abstracts in English
Hishinuma, Akimichi; Tabuchi, Masayuki; Sawai, Tomotsugu
Intermetallics, 7(8), p.875 - 879, 1999/00
Times Cited Count：10 Percentile：59.54(Chemistry, Physical)no abstracts in English
Sawai, Tomotsugu; Shiba, Kiyoyuki; Hishinuma, Akimichi
Journal of Nuclear Materials, 258-263, p.1997 - 2001, 1998/00
Times Cited Count：3 Percentile：31.81(Materials Science, Multidisciplinary)no abstracts in English
Shiba, Kiyoyuki; Hishinuma, Akimichi; *; *
JAERI-Tech 97-038, 110 Pages, 1997/08
no abstracts in English
Sawai, Tomotsugu; Shiba, Kiyoyuki; Fukai, Katsumaro; Hishinuma, Akimichi
6WS-96: 6th Int. Welding Symp. on the Role of Welding Science and Technology in the 21st Century, 2, p.483 - 488, 1996/00
no abstracts in English
Tsukada, Takashi; Miwa, Yukio; Shindo, Masami
Fourth Japan-China Symp. on Mater. for Advanced Energy Systems and Fission and Fusion Engineering '96, 0, p.223 - 227, 1996/00
no abstracts in English
Miwa, Yukio; Tsukada, Takashi; Jitsukawa, Shiro; Kita, Satoshi; Hamada, Shozo; Matsui, Yoshinori; Shindo, Masami
Journal of Nuclear Materials, 233-237(PT.B), p.1393 - 1396, 1996/00
Times Cited Count：15 Percentile：76.16(Materials Science, Multidisciplinary)no abstracts in English
Hishinuma, Akimichi
Journal of Nuclear Materials, 239(1-3), p.267 - 272, 1996/00
Times Cited Count：20 Percentile：82.77(Materials Science, Multidisciplinary)no abstracts in English
Sawai, Tomotsugu; Fukai, Katsumaro; Hishinuma, Akimichi
Microstructures and Functions of Materials (ICMFM 96), 0, p.257 - 260, 1996/00
no abstracts in English
Suzuki, Masahide; Sawai, Tomotsugu; P.J.Maziasz*; Hishinuma, Akimichi
Journal of Nuclear Materials, 179-181, p.718 - 721, 1991/00
Times Cited Count：5 Percentile：53.87(Materials Science, Multidisciplinary)no abstracts in English
C; P.J.Maziasz*; ; Hamada, S.
Journal of Nuclear Materials, 141-143, p.943 - 947, 1986/00
Times Cited Count：25 Percentile：89.88(Materials Science, Multidisciplinary)no abstracts in English
; Katano, Y.; Shiraishi, K.
Journal of Nuclear Science and Technology, 21(9), p.671 - 677, 1984/00
Times Cited Count：14 Percentile：79.2(Nuclear Science & Technology)no abstracts in English
Katsuyama, Jinya; Takamizawa, Hisashi; Ha, Yoosung; Nishiyama, Yutaka; Onizawa, Kunio
no journal, ,
We will present microstructure analysis results obtained by SEM and APT and so on for heat affected zone (HAZ) materials. The effects of microstructures such as grain size, phase fraction and martensite-austenite constituent on fracture toughness of HAZ materials were investigated. Also, the effects of solute cluster in the matrix and segregation near the carbide on irradiation embrittlement susceptibility will be discussed.
