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Shobu, Takahisa; Zhang, S.; Shiro, Ayumi; Muramatsu, Toshiharu; Yamada, Tomonori; Kono, Fumiaki; Ozawa, Takayuki
no journal, ,
no abstracts in English
Zhang, S.; Shobu, Takahisa; Shiro, Ayumi; Hashimoto, Tadafumi*; Tsuji, Akihiro*; Okano, Shigetaka*; Mochizuki, Masahito*
no journal, ,
no abstracts in English
Suzuki, Hiroshi; Harjo, S.; Abe, Jun*; Aizawa, Kazuya; Akita, Koichi
no journal, ,
Effects of pseudo-strains, due to influences of the surface effect and neutron attenuation, on the strain measurement by Time-of-Flight neutron diffraction were discussed using the TAKUMI engineering diffractometer at MLF of J-PARC. Typical pseudo-strains due to the surface-effect were appeared in near-surface strain measurements when a gauge volume is incompletely filled in a sample. Furthermore, a pseudo-strain due to change in the ncog (neutron-weighted center of gravity) position was observed even when perfectly immersing the gauge volume in a sample, and it was increased with an increase of the gauge volume. These pseudo-strains measured were well simulated by taking into account an incident neutron beam divergence additionally in the conventional model. Therefore, it was clarified that the incident neutron beam divergence must be an important parameter to make a modeling of pseudo-strains induced in the strain measurement using the TOF engineering diffractometer.
Akita, Koichi; Suzuki, Hiroshi; Moriai, Atsushi; Harjo, S.; Nishikawa, Satoru*
no journal, ,
To clarify the relaxation process on dissimilar metal weld joints, 
stress measurements during thermal cycles from RT to 593 K were conducted using a neutron engineering diffractometer, TAKUMI in J-PARC. The effects of the difference in thermal expansion coefficient of the materials and the temperature dependence of the yield strength on the residual stress relaxation were discussed based on the experimental results.
measurement of lattice strain under plastic deformation in Aluminum single crystalShiro, Ayumi; Shobu, Takahisa; Okada, Tatsuya*; Kawano, Tomoya*; Bunya, Hirotomo*
no journal, ,
Aluminum single crystals deformed along the 
111
direction exhibit a macroscopically uniform multiple-slip without deformation bands. In a previous study, it was found that the residual strain of Al single crystal deformed to a tensile strain of 8% to the 111 direction is very small. In this study, in order to clarify the strain distribution under tensile deformation, we carried out the measurement using 2-dimensional detector. As a result, it was found as follows: (1) The width of diffraction spots were broadening as a plastic deformation was large. (2) Three subcrystals existed in the aluminum single crystal, and each subcrystal has different strain. (3) The relationship between the width of diffraction spot and formation behavior of the internal dislocation substructure existed.