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Onodera, Naoto*; Ishii, Akito*; Ishii, Koji*; Iwase, Akihiro*; Yokoyama, Yoshihiko*; Saito, Yuichi; Ishikawa, Norito; Yabuuchi, Atsushi*; Hori, Fuminobu*
Nuclear Instruments and Methods in Physics Research B, 314, p.122 - 124, 2013/11
Times Cited Count:3 Percentile:25.98(Instruments & Instrumentation)It has been reported that heavy ion irradiation causes softening in some cases of Zr-based bulk metallic glass alloys. However, the fundamental mechanisms of such softening have not been clarified yet. In this study, ZrCuAl bulk glassy alloys were irradiated with heavy ions of 10 MeV I at room temperature. Positron annihilation measurements have performed before and after irradiation to investigate changes in free volume. We discuss the relationship between the energy loss and local open volume change after 10 MeV I irradiation compared with those obtained for 200 MeV Xe and 5 MeV Al. The energy loss analysis in ion irradiation for the positron lifetime has revealed that the decreasing trend of positron lifetime is well expressed as a function of total electronic energy deposition rather than total elastic energy deposition. It means that the positron lifetime change by the irradiation has a relationship with the inelastic collisions with electrons during heavy ion irradiation.
Hori, Fuminobu*; Onodera, Naoto*; Fukumoto, Yuka*; Ishii, Akito*; Iwase, Akihiro*; Kawasuso, Atsuo; Yabuuchi, Atsushi; Maekawa, Masaki; Yokoyama, Yoshihiko*
Journal of Physics; Conference Series, 262, p.012025_1 - 012025_4, 2011/01
Times Cited Count:5 Percentile:84.24(Physics, Applied)Free volume changes in ZrCuAl bulk glassy alloys irradiated by 200 and 2.5 MeV Xe ions, 180 keV He ions, and 2 MeV electrons were investigated at room temperature using positron annihilation techniques. X-ray diffraction revealed that no crystallization took place in any of the irradiated sample. The positron lifetime increased only after electron and 180 keV He irradiation. This indicates that the radiation has increased the open volume size (free volume). On the other hand, the positron lifetime was decreased by irradiation with heavy Xe-ions at either energy of 2.5 or 200 MeV. It is conceivable that the difference in behavior can be attributed to the difference in displacements per radiation particle (dpp), because the dpp estimated for 2 MeV electrons and 180 keV He ions is three or more orders of magnitude less than that for heavy Xe ions. We found that the radiation effect in ZrCuAl bulk glassy alloy is dependent on the displacement per radiation particle.
Kaneko, Koji; Metoki, Naoto; Oyama, Kenji*; Onodera, Hideya*; Yamaguchi, Yasuo*
Journal of Magnetism and Magnetic Materials, 272-276(Suppl.), p.e375 - e376, 2004/05
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)no abstracts in English