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ABSTRACT: An in-situ straining device has been developed, which enables one to apply a load of 240 N to a specimen in hot water at 561 K and a pressure of 8 MPa, simulating the environment in a boiling water reactor (BWR). The device is equipped with sapphire glass windows for a light path, that is, the device can be used for dynamic measurements of stress induced in the specimen using a synchrotron radiation facility. In-situ stress measurements have been carried out at SPring-8 (BL02B1) on a specimen prepared from SUS316L stainless steel. Inhomogeneity in stress distribution and time-dependent changes in stress were successfully measured.
AIP Conference Proceedings 01/2007; 879(1).
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ABSTRACT: Suppressing the stress corrosion cracking (SCC) by reducing the carbon content in austenitic stainless steels is apparently not effective on core shrouds used in boiling water reactors in Japan: trans-granular cracking was found in the shrouds. To clarify the mechanism of the cracking, in situ stress measurements on specimens under stretched conditions in hot water have been attempted in the present study. An in situ device for diffraction measurements at synchrotron radiation facilities has been developed, and in situ experiments have been carried out at SPring-8. The SUS316L steel specimen was solution heat-treated, surface-ground and then placed in the in situ device. Sapphire windows were used for the light path in the device. A sufficient diffracted beam intensity was obtained through two sapphire windows and water. The side-inclination method was used for measuring the stress exerted on the specimen. A 2theta-sin2psi plot showed that a tensile stress was induced. The measured stress value is considered to be the summation of stresses owing to pre-straining, in situ loading and residual stress owing to surface grinding.
Journal of Synchrotron Radiation 02/2006; 13(Pt 1):14-8. · 2.73 Impact Factor
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ABSTRACT: Austenitic stainless steel specimens of Type 316SS were irradiated with 200 keV He+ or N+ ions, and the irradiated specimen surfaces were observed by atomic force microscopy (AFM). At the ion irradiation in high temperatures the specimens show surface step-up. In case of He+, the surface swelling is remarkable and increases linearly with He ion fluence, which indicates the swelling is due to formation of He bubbles. The irradiated surface is sometimes in irregularity, especially at and near grain boundary, remarkable ridging is observed. In case of N+, the surface step-up is less remarkable compared with He+. The swelling shows a so-called bi-linear behavior, i.e. a threshold of N+ fluence appears and beyond the threshold the swelling increase is almost linearly presumably due to evolution of voids induced by the N+ irradiation in high temperature. Denudation of void formation adjacent to grain boundary is recognized.
Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 193:329-335. · 1.21 Impact Factor
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ABSTRACT: The precipitation of Pb–0.08% Ca–1.5% Sn alloys with 0.04% Ag or 0.03% Bi additions was studied by resistivity measurements and transmission electron microscopy (TEM). The addition of Ag or Bi to the Pb–Ca–Sn ternary alloys suppresses discontinuous precipitation and accelerates the formation of continuous precipitates with high coherency strain. Ag addition has a greater effect on hardening than Bi addition. TEM-energy dispersive spectroscopy (EDS) analysis confirmed that the continuous precipitates formed in Ag-supplemented alloys contain Ag in addition to Ca, Sn and Pb elements.
Journal of Power Sources 158(2):897-901. · 4.95 Impact Factor
