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Aihara, Jun; Hojo, Kiichi; Furuno, Shigemi*; Hojo, Tomohiro; Sawa, Kazuhiro; Yamamoto, Hiroyuki; Motohashi, Yoshinobu*
Materials Transactions, 48(7), p.1896 - 1900, 2007/07
Times Cited Count:0 Percentile:0.01(Materials Science, Multidisciplinary)Silicon carbide(SiC) TEM specimens were annealed, in-situ, at 1273K for 30 minutes after amorphization with 30keV Ne irradiation to the fluence of 1.9 or 2.310Ne/m at 573K or about 98K. The crystal nucleation and bubble coalescence accompanied by recrystallization were observed in both specimens with the annealing after the irradiations. 2.310Ne/m irradiations in both specimens. The Debye-Sherrer rings of the nucleated crystals well fitted the net pattern of the matrix, even though no ring corresponding to (200) of -SiC appeared. Dependence of the crystal nucleation behavior on irradiation temperature was not observed within the present experimental range.
Hojo, Tomohiro*; Yamamoto, Hiroyuki; Aihara, Jun; Furuno, Shigemi*; Sawa, Kazuhiro; Sakuma, Takashi*; Hojo, Kiichi
Nuclear Instruments and Methods in Physics Research B, 250(1-2), p.101 - 105, 2006/09
Times Cited Count:6 Percentile:43.74(Instruments & Instrumentation)Yttria stabilized zirconia (YSZ) is a candidate material focused as optical and insulating materials in nuclear reactors. Therefore, it is useful to investigate defect formation during irradiation, in order to assess YSZ resistance to radiation damage. In the present study, in situ transmission electron microscopy (TEM) observations were performed on YSZ during 30 keV Ne irradiation in the temperature range of 723-1123 K. For irradiations below 1023 K, defect clusters and bubbles were formed simultaneously. On the other hand, at 1123 K, only bubbles were formed in the initial stage of irradiation. Loops formed later following the bubble formation. It was also observed that, in the early stage of irradiation above 923 K, larger bubbles were formed along the loop planes compared with other areas. TEM observations indicated that dislocation loops formed on three kinds of crystallographic planes: namely, (100), (111) and (112) planes.
Hojo, Tomohiro*; Yamamoto, Hiroyuki; Aihara, Jun; Furuno, Shigemi*; Sawa, Kazuhiro; Sakuma, Takashi*; Hojo, Kiichi
Nuclear Instruments and Methods in Physics Research B, 250(1-2), p.123 - 127, 2006/09
Times Cited Count:2 Percentile:21.02(Instruments & Instrumentation)Spinel and yttria stabilized zirconia (YSZ) are candidates for fuel materials for use in nuclear reactors and the optical and insulating materials for fusion reactors. In the present study, the damage evolution process of polycrystalline spinel-YSZ composite materials has been studied by in situ transmission electron microscope observation during ion irradiation. The irradiation was performed with 30 keV Ne at a flux of 5 10 ions/cm per second at 923 K and 1473 K, respectively. At 923 K, defect clusters and bubbles were formed homogeneously in YSZ grains. On the other hand, at 1473 K, only bubble formation was observed. The bubbles grew remarkably with increasing ion fluence in both grains. Even though the growth of the bubbles was observed in both grains, the average diameter of grown bubbles in spinel grains was larger than those in YSZ ones. The bubbles tended to form along the grain boundary at both temperatures.
Aihara, Jun; Hojo, Kiichi; Furuno, Shigemi*; Shimura, Kenichiro; Hojo, Tomohiro*; Sawa, Kazuhiro; Yamamoto, Hiroyuki; Motohashi, Yoshinobu*
Nuclear Instruments and Methods in Physics Research B, 242(1-2), p.441 - 444, 2006/01
Times Cited Count:1 Percentile:12.81(Instruments & Instrumentation)no abstracts in English
Aihara, Jun; Hojo, Tomohiro*; Furuno, Shigemi*; Ishihara, Masahiro; Sawa, Kazuhiro; Yamamoto, Hiroyuki; Hojo, Kiichi
Nuclear Instruments and Methods in Physics Research B, 241(1-4), p.559 - 562, 2005/12
Times Cited Count:5 Percentile:40.98(Instruments & Instrumentation)Silicon carbide (SiC) specimens prepared for the TEM (transmission electron microscope) observation were amorphized with 30keV Ne or 4.5keV He ion irradiation at room temperature and successively annealed at 1273K in the TEM. Ne and He were selected as irradiation ion species to change the concentration of implanted rare gas atoms. The energy and flux of these ion species were selected in order to get similar dpa depth profiles and dpa rates based on TRIM calculation. In this condition, peak ion implantation of He was estimated to be about 5 times as large as that of Ne for the same peak dpa. Crystal nucleation occurred with annealing in the specimen irradiated with He up to 6.3dpa(peak), however, no crystal nucleation was observed in the specimen irradiated with Ne up to 15dpa(peak); Namely, crystal nucleation occurred with less dpa in the case of He irradiation than in the case of Ne irradiation. It was found that the concentration of implanted inert gas atom influences the crystal nucleation behavior.
Aihara, Jun; Sawa, Kazuhiro; Furuya, Yoshio*; Hojo, Tomohiro*; Furuno, Shigemi*; Yamamoto, Hiroyuki; Hojo, Kiichi; Ishihara, Masahiro
Journal of the American Ceramic Society, 88(8), p.2319 - 2321, 2005/08
Times Cited Count:0 Percentile:0.02(Materials Science, Ceramics)no abstracts in English
Aihara, Jun; Ishihara, Masahiro; Hojo, Kiichi; Furuno, Shigemi*
Journal of the American Ceramic Society, 87(6), p.1146 - 1148, 2004/06
Times Cited Count:1 Percentile:18.32(Materials Science, Ceramics)SiC specimens were amorphized with Ne irradiation and annealed at 1273K. One specimen was annealed continuously for 60 minutes, the other was annealed repeatedly (5 minutes 10 times). Crystal nucleation in the amorphized SiC was apt to occur more in the case of repeated annealing than in the case of continuous annealing.
Aihara, Jun; Hojo, Kiichi; Furuno, Shigemi*; Ishihara, Masahiro; Yamamoto, Hiroyuki
Proceedings of 8th Asia-Pacific Conference on Electron Microscopy (8APEM) (CD-ROM), p.722 - 723, 2004/06
SiC TEM specimens were irradiated with 20keV Ne+ to the fluence of 1.5x10Ne+/m at 573, 583, 598 and 683K, and successively annealed at 1273K for 30minutes. In the cases of 573 and 583K irradiation, amorphization with irradiation and crystal nucleation with annealing occurred. Coalescence of the bubbles was clearly observed in the crystal nucleated area and epitaxial growth area. In the case of 593K irradiation, partial amorphization occurred but crystal nucleation did not occur. In the case of 673K irradiation, amorphization did not occur and no change was observed after annealing.
Hojo, Tomohiro; Aihara, Jun; Hojo, Kiichi; Furuno, Shigemi*; Yamamoto, Hiroyuki; Nitani, Noriko; Yamashita, Toshiyuki; Minato, Kazuo; Sakuma, Takaaki*
Journal of Nuclear Materials, 319, p.81 - 86, 2003/06
Times Cited Count:18 Percentile:74.27(Materials Science, Multidisciplinary)no abstracts in English
Hojo, Kiichi; Hojo, Tomohiro; Sasajima, Naohiko*; Shirasu, Noriko; Yamashita, Toshiyuki; Minato, Kazuo; Furuno, Shigemi*
AIP Conference Proceedings 680, p.647 - 652, 2003/00
no abstracts in English
Wakai, Eiichi; Miwa, Yukio; Hashimoto, Naoyuki*; Robertson, J. P.*; Klueh, R. L.*; Shiba, Kiyoyuki; Abiko, Kenji*; Furuno, Shigemi*; Jitsukawa, Shiro
Journal of Nuclear Materials, 307-311(Part.1), p.203 - 211, 2002/12
Times Cited Count:26 Percentile:82.20(Materials Science, Multidisciplinary)no abstracts in English
Aihara, Jun; Hojo, Kiichi; Furuno, Shigemi*; Ishihara, Masahiro; Hayashi, Kimio
Journal of Electron Microscopy, 51(2), p.93 - 98, 2002/05
Times Cited Count:6 Percentile:20.46(Microscopy)no abstracts in English
Aihara, Jun; Hojo, Kiichi; Furuno, Shigemi*; Ishihara, Masahiro
Nuclear Instruments and Methods in Physics Research B, 191(1-4), p.540 - 543, 2002/05
Times Cited Count:4 Percentile:29.31(Instruments & Instrumentation)no abstracts in English
Aihara, Jun; Hojo, Kiichi; Furuno, Shigemi; Ishihara, Masahiro; Hayashi, Kimio
Nuclear Instruments and Methods in Physics Research B, 166-167, p.379 - 384, 2000/05
Times Cited Count:8 Percentile:50.58(Instruments & Instrumentation)no abstracts in English
Sasajima, N.*; Matsui, Tsuneo*; Furuno, Shigemi*; Hojo, Kiichi; Shiratori, Tetsuo
Nuclear Instruments and Methods in Physics Research B, 166-167, p.250 - 257, 2000/00
Times Cited Count:20 Percentile:76.36(Instruments & Instrumentation)no abstracts in English
Muto, Shunsuke*; Tanabe, Tetsuo*; ; ; Furuno, Shigemi*; Hojo, Kiichi
Journal of Nuclear Materials, 271-272, p.285 - 289, 1999/00
Times Cited Count:5 Percentile:40.57(Materials Science, Multidisciplinary)no abstracts in English
Hojo, Kiichi; ; Furuno, Shigemi*; ; Kushita, Kohei; Sasajima, Naohiko*
Nuclear Instruments and Methods in Physics Research B, 148(1-4), p.720 - 725, 1999/00
Times Cited Count:4 Percentile:38.39(Instruments & Instrumentation)no abstracts in English
Sasajima, Naohiko*; Matsui, Tsuneo*; Furuno, Shigemi*; Hojo, Kiichi;
Nuclear Instruments and Methods in Physics Research B, 148(1-4), p.745 - 751, 1999/00
Times Cited Count:36 Percentile:90.60(Instruments & Instrumentation)no abstracts in English
Furuno, Shigemi*; Sasajima, N.*; Hojo, Kiichi; ; ; Matsui, Tsuneo*
Journal of Nuclear Materials, 258-263, p.1817 - 1821, 1998/00
Times Cited Count:8 Percentile:57.22(Materials Science, Multidisciplinary)no abstracts in English
Hojo, Kiichi; ; Furuno, Shigemi; Kushita, Kohei; ; Sasajima, Naohiko*
Nuclear Instruments and Methods in Physics Research B, 141(1-4), p.148 - 153, 1998/00
Times Cited Count:31 Percentile:89.51(Instruments & Instrumentation)no abstracts in English