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Sekio, Yoshihiro; Sakaguchi, Norihito*
Materials Transactions, 60(5), p.678 - 687, 2019/05
Times Cited Count：5 Percentile：28.5(Materials Science, Multidisciplinary)The quantitative evaluation of vacancy migration energies in high nickel model alloy was conducted by analyzing the void denuded zone (VDZ) width formed near grain boundaries under neutron and electron irradiation. The microstructures of Fe-15Cr-xNi (x=15, 20, 25, 30 mass%) alloys that were neutron irradiated at 749 K and electron irradiated at 576 K-824 K were examined. The VDZ widths increased with increasing Ni content in both irradiation experiments, which implies an increase of the vacancy mobility. The vacancy migration energies were estimated from the temperature dependence of the VDZ widths, and the energies were 1.09, 0.97, 0.90, and 0.77 eV for the alloys containing 15, 20, 25, and 30 mass% Ni, respectively. From the obtained energies, the effective vacancy diffusivity and excess vacancy concentration were estimated using the analytical equation of the VDZ width, which quantitatively confirmed the increase of the vacancy mobility with increasing Ni content.
Iwase, Akihiro*; Chimi, Yasuhiro; Ishikawa, Norito; Nakatani, Rikizo*; Kato, Yuzaburo*; Fukuzumi, Masafumi*; Tsuchida, Hidetsugu*; Baba, Yuji
Nuclear Instruments and Methods in Physics Research B, 245(1), p.141 - 144, 2006/04
Times Cited Count：0 Percentile：0.01(Instruments & Instrumentation)Diffusion of Si atoms in Pd under energetic ion irradiation is studied in Pd-Si thin layer system using synchrotron radiation photoemission spectroscopy. Specimens are prepared by depositing Pd on Si single crystals. The Pd layer thicknesses are 10-300 nm. Before irradiation, we observe photoemission spectra only for Pd, but do not find any trace of Si. After irradiation with 3-MeV Si ions, 1-MeV O ions or 200-MeV Xe ions, we observe an additional photoemission component at the binding energy about 3 eV higher than that of Si 1s bulk component. The experimental result implies that the energetic ion-irradiation induces the diffusion of Si atoms from the Si-Pd interface to the Pd layer surface. The shift of the binding energy from the value for the Si bulk can be interpreted as arising from electron charge transfer from Si to Pd. The dependences of photoemission spectra and ion-irradiation induced diffusion on ion-species and ion-fluence are discussed.
