Refine your search:     
Report No.
Search Results: Records 1-20 displayed on this page of 40

Presentation/Publication Type

Initialising ...


Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...


Initialising ...


Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Determination of atomistic deformation of tricalcium silicate paste with high-volume fly ash

Jee, H.*; Im, S.*; Kanematsu, Manabu*; Suzuki, Hiroshi; Morooka, Satoshi; Koyama, Taku*; Machida, Akihiko*; Bae, S.*

Journal of the American Ceramic Society, 103(12), p.7188 - 7201, 2020/12

 Times Cited Count:2 Percentile:43.78(Materials Science, Ceramics)

Journal Articles

Hydrogen embrittlement resistance of pre-strained ultra-high-strength low alloy TRIP-aided steel

Hojo, Tomohiko*; Kumai, B.*; Koyama, Motomichi*; Akiyama, Eiji*; Waki, Hiroyuki*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Nagasawa, Akihiko*

International Journal of Fracture, 224(2), p.253 - 260, 2020/08

 Times Cited Count:4 Percentile:71.2(Materials Science, Multidisciplinary)

In the study, the pre-strain effect on hydrogen embrittlement property of the ultra-high-strength transformation-induced plasticity -aided bainitic ferrite steel was investigated towards application for automobile frame parts. 3-10% tensile pre-strain suppressed hydrogen-induced mechanical degradation relative to total elongation while 12-15% pre-strained specimen did not exhibit elongation after hydrogen charging. The advantageous effect of the 3-10% pre-strain was attributed to the suppression of crack initiation related to retained austenite. The TRIP by pre-straining decreased the volume fraction of retained austenite before hydrogen charging, thereby reducing existing probabilities of preferential crack initiation sites and propagation paths. Conversely, high pre-strain such as 12-15% does not effectively work due to work hardening resulting in increases in hydrogen embrittlement susceptibility and a significant increase in hydrogen content due to the multiplication of dislocations.

Journal Articles

Analysis of atomistic structural deformation characteristics of calcium silicate hydrate in 53-year-old tricalcium silicate paste using atomic pair distribution function

Bae, S.*; Jee, H.*; Suh, H.*; Kanematsu, Manabu*; Shiro, Ayumi*; Machida, Akihiko*; Watanuki, Tetsu*; Shobu, Takahisa; Morooka, Satoshi; Geng, G.*; et al.

Construction and Building Materials, 237, p.117714_1 - 117714_10, 2020/03

 Times Cited Count:4 Percentile:73.39(Construction & Building Technology)

Journal Articles

Stress measurement of coarse grains using double exposure method

Suzuki, Kenji*; Shobu, Takahisa; Shiro, Ayumi*

Zairyo, 68(4), p.312 - 317, 2019/04

Materials after thermal processing such as welding often have coarse grains. To understand the residual stress after processing is very important from the viewpoint of the soundness of the structure. In this study, we proposed a double exposure method that combines a two-dimensional detector and high-energy synchrotron radiation as an X-ray stress measurement method for materials with coarse grains, and confirmed its practicality. As a result of measuring the residual stress of the plastic bending specimen and the indentation specimen of the aluminum alloy (A5052), the effectiveness of this measurement method was clarified because the residual stress distribution was in good agreement with the finite element analysis.

Journal Articles

Pair distribution function analysis of nanostructural deformation of calcium silicate hydrate under compressive stress

Bae, S.*; Jee, H.*; Kanematsu, Manabu*; Shiro, Ayumi*; Machida, Akihiko*; Watanuki, Tetsu*; Shobu, Takahisa; Suzuki, Hiroshi

Journal of the American Ceramic Society, 101(1), p.408 - 418, 2018/01

 Times Cited Count:9 Percentile:62.04(Materials Science, Ceramics)

Despite enormous interest in calcium silicate hydrate (C-S-H), its detailed atomic structure and intrinsic deformation under an external load are lacking. This study demonstrates the nanostructural deformation process of C-S-H in tricalcium silicate (C$$_{3}$$S) paste as a function of applied stress by interpreting atomic pair distribution function (PDF) based on in situ X-ray scattering. Three different strains in C$$_{3}$$S paste under compression were compared using a strain gauge and the real and reciprocal space PDFs. PDF refinement revealed that the C-S-H phase mostly contributed to PDF from 0 to 20${AA}$ whereas crystalline phases dominated that beyond 20${AA}$. The short-range atomic strains exhibited two regions for C-S-H: I) plastic deformation (0-10 MPa) and II) linear elastic deformation ($$>$$10 MPa), whereas the long-range deformation beyond 20${AA}$ was similar to that of Ca(OH)$$_{2}$$. Below 10 MPa, the short-range strain was caused by the densification of C-S-H induced by the removal of interlayer or gel-pore water. The strain is likely to be recovered when the removed water returns to C-S-H.

Journal Articles

Strain measurement in Ti layers of CFRP/Ti laminates by synchrotron X-ray diffraction

Akita, Koichi; Nakatani, Hayato*; Ogihara, Shinji*; Shobu, Takahisa; Shiro, Ayumi*; Igawa, Naoki; Shimojo, Yutaka

SPring-8/SACLA Riyo Kenkyu Seikashu (Research Report) (Internet), 6(1), p.105 - 108, 2018/01

no abstracts in English

Journal Articles

Local structure analysis of (Na$$_{0.5}$$K$$_{0.45}$$Li$$_{0.05}$$)NbO$$_3$$ synthesized by malic acid complex solution method

Yoneda, Yasuhiro; Takada, Eri*; Nagai, Haruka*; Kikuchi, Takeyuki*; Morishita, Masao*; Kobune, Masafumi*

Japanese Journal of Applied Physics, 56(10S), p.10PB07_1 - 10PB07_7, 2017/10

 Times Cited Count:3 Percentile:21.75(Physics, Applied)

A monoclinic phase was discovered in (Na$$_{0.5}$$K$$_{0.45}$$Li$$_{0.05}$$)NbO$$_3$$ solid solution ceramics grown by a malic acid complex solution method. The average and local structures of this monoclinic phase were analyzed by synchrotron X-ray measurements. The local structure can be reproduced by assuming a rhombohedral model, that is the same local structure of KNbO$$_3$$. The results demonstrate that the monoclinic average structure is observed as a disordered rhombohedral structure.

Journal Articles

Local deformation analysis in martensite layer of high-strength multilayered steel composite using synchrotron X-ray diffraction

Ojima, Mayumi*; Shiro, Ayumi*; Suzuki, Hiroshi; Inoue, Junya*; Shobu, Takahisa; Xu, P. G.; Akita, Koichi; Nambu, Shoichi*; Koseki, Toshihiko*

Zairyo, 66(6), p.420 - 426, 2017/06

Journal Articles

Quantitative analysis of tempering microstructure via ${it in-situ}$ synchrotron X-ray diffraction during heating

Morooka, Satoshi; Kanata, Hiroyuki*; Oba, Yojiro*; Sato, Masugu*

Heisei-28-Nendo SPring-8 Sangyo Shinbunya Shien Kadai, Ippan Kadai (Sangyo Bunya) Jisshi Hokokusho, p.95 - 98, 2017/00

no abstracts in English

Journal Articles

In-situ measurement of transitional stress in welds metal of steel using synchrotron radiation

Tsuji, Akihiro*; Zhang, S.*; Hashimoto, Tadafumi*; Okano, Shigetaka*; Shobu, Takahisa; Mochizuki, Masahito*

Zairyo, 65(9), p.665 - 671, 2016/09

It is necessary to control weld residual stress which has negative influence on fracture strengths. In structural steel welds, complex residual stress fields are formed due to phase transformation that occur according to the thermal cycles. In this study, in-situ evaluation of phase transformation and transitional stress simultaneously during welding is discussed. In the test using SM490A, after cooling process, stress evaluated by this system showed good agreement with that evaluated by lab X-ray. During austenite to ferrite transformation in weld metal, tensile stress occurred in austenite and compressive stress occurred in ferrite. Moreover, stress concentration was occurred in ferrite phase immediately after the start of phase transformation. Also, stress concentration was occurred in austenite phase just before the end of phase transformation.

Journal Articles

Non-destructive depth analysis of the surface oxide layer on Mg$$_{2}$$Si with XPS and XAS

Esaka, Fumitaka; Nojima, Takehiro; Udono, Haruhiko*; Magara, Masaaki; Yamamoto, Hiroyuki

Surface and Interface Analysis, 48(7), p.432 - 435, 2016/07

 Times Cited Count:7 Percentile:25.29(Chemistry, Physical)

XPS is widely used for non-destructive chemical state analysis of solid materials. In this method, depth profiling can be carried out by a combination with ion beam sputtering. However, the sputtering often causes segregation and preferential sputtering of atoms and gives inaccurate information. The use of energy-tunable X-rays from synchrotron radiation (SR) enables us to perform non-destructive depth profiling in XPS. Here, the analytical depth can be changed by changing excitation X-ray energy. In the present study, we examined methods to perform depth profiling with XPS by changing excitation energy and XAS by changing electron energy for detection. These methods were then applied to the analysis of native surface oxide layers on Mg$$_{2}$$Si crystals. In this XAS analysis, the peak at 1843.4 eV becomes dominant when the electron energy for detection increases, which implies that Si-O or Si-O-Mg structure is formed as the surface oxide layer on the Mg$$_{2}$$Si.

Journal Articles

Presence of $$varepsilon$$-martensite as an intermediate phase during the strain-induced transformation of SUS304 stainless steel

Hatano, Masaharu*; Kubota, Yoshiki*; Shobu, Takahisa; Mori, Shigeo*

Philosophical Magazine Letters, 96(6), p.220 - 227, 2016/06

 Times Cited Count:6 Percentile:41.38(Materials Science, Multidisciplinary)

We have investigated the formation process of $$alpha$$'-martensite from the $$gamma$$-phase induced by external strain using ${it in situ}$ synchrotron diffraction experiments, combined with Lorentz transmission electron microscopy (TEM) and high-resolution TEM observations. It is clearly demonstrated that $$varepsilon$$-martensite with hexagonal symmetry appears as an intermediate structure during the plastic deformation of SUS304 stainless steel. In addition to stacking faults and dislocations, interfaces between the twin structures presumably play a key role in the formation of $$varepsilon$$-martensite.

Journal Articles

Investigation of elastic deformation mechanism in as-cast and annealed eutectic and hypoeutectic Zr-Cu-Al metallic glasses by multiscale strain analysis

Suzuki, Hiroshi; Yamada, Rui*; Tsubaki, Shinki*; Imafuku, Muneyuki*; Sato, Shigeo*; Watanuki, Tetsu; Machida, Akihiko; Saida, Junji*

Metals, 6(1), p.12_1 - 12_11, 2016/01

 Times Cited Count:3 Percentile:24.17(Materials Science, Multidisciplinary)

Elastic deformation behaviors of as-cast and annealed eutectic and hypoeutectic Zr-Cu-Al bulk metallic glasses (BMGs) were investigated on a basis of different strain-scales determined by X-ray scattering and the strain gauge. The microscopic strains determined by Direct-space method (DSM) and Q-space method (QSM) were compared with the macroscopic strain measured by the strain gauge, and the difference in the deformation mechanism between eutectic and hypoeutectic Zr-Cu-Al BMGs was investigated by their correlation. The eutectic Zr$$_{50}$$Cu$$_{40}$$Al$$_{10}$$ BMG obtains more homogeneous microstructure by free-volume annihilation after annealing, improving a resistance to deformation but degrading ductility because of a decrease in the volume fraction of WBRs (Weakly-Bonded Regions) with relatively high mobility. On the other hand, the as-cast hypoeutectic Zr$$_{60}$$Cu$$_{30}$$Al$$_{10}$$ BMG originally has homogeneous microstructure, but loses its structural and elastic homogeneities because of nanocluster formation after annealing. Such structural changes after annealing might develop unique mechanical properties showing no degradations of ductility and toughness for the structural-relaxed hypoeutectic BMGs.

Journal Articles

Negative correlation between electrical response and domain size in a Ti-composition-gradient Pb[(Mg$$_{1/3}$$Nb$$_{2/3}$$)$$_{1-x}$$Ti$$_{x}$$]O$$_{3}$$ crystal near the morphotropic phase boundary

Shimizu, Daisuke*; Tsukada, Shinya*; Matsuura, Masato*; Sakamoto, Junya*; Kojima, Seiji*; Namikawa, Kazumichi*; Mizuki, Junichiro; Owada, Kenji

Physical Review B, 92(17), p.174121_1 - 174121_5, 2015/11

 Times Cited Count:10 Percentile:49.16(Materials Science, Multidisciplinary)

The phase diagram and the relationship between the crystal coherence length and electrical response of Pb[(Mg$$_{1/3}$$Nb$$_{2/3}$$)$$_{1-x}$$Ti$$_{x}$$]O$$_{3}$$ (PMN-xPT) near the morphotropic phase boundary (MPB) have been precisely investigated using a single crystal with a Ti composition gradient by synchrotron X-ray diffraction and inelastic light scattering at room temperature. The crystal has two boundaries at Ti compositions of 29.0 mol% and 34.7 mol% which correspond to the phase boundaries between the monoclinic B (MB) and C (MC) phases and between the MC and tetragonal (T) phases, respectively. It is shown that there is a strong negative correlation between the electrical response and the crystal coherence length at the sub-$$mu$$m scale. The results are explained by the size effects of domains near the MPB.

Journal Articles

Depth analysis of the surface of Mg$$_{2}$$Si crystals with XAS and XPS

Yamamoto, Hiroyuki; Nojima, Takehiro; Esaka, Fumitaka

Photon Factory Activity Report 2014, Part B, P. 112, 2015/00

In order to develop silicon-based electronic devices, metal silicides are widely studied. Information of the surface chemical states of metal silicides is important to obtain homo-epitaxial films with excellent quality. In this work, depth analysis of surface chemical states of Mg$$_{2}$$Si crystals is carried by XPS. Depth analysis is also performed in XAS measurement with a partial electron yield (PEY) mode. The Si 1s XPS spectra of the cleaved surface of the Mg$$_{2}$$Si crystal indicates that SiO is formed on the surface of the Mg$$_{2}$$Si crystal. Here, no peak assigned to SiO$$_{2}$$ structure is observed. The Si K-edge XAS spectra obtained with the PEY mode show a peak at 1843.7 eV, which can be assigned to SiO structure.

Journal Articles

Non-destructive depth profiling of Au/Si(100) with X-ray absorption spectroscopy

Yamamoto, Hiroyuki; Nojima, Takehiro; Esaka, Fumitaka

Photon Factory Activity Report 2013, Part B, P. 227, 2014/00

In the present study, we examined to perform depth profiling with X-ray absorption spectroscopy (XAS) by changing electron energies (5-50 eV) for detection in order to develop non-destructive depth profiling method with chemical state information. Gold thin films (1-10 nm) deposited on Si(100) were used for specimens. The Si/Au ratios were calculated from the peak heights of each edge using observed XAS spectra. Obvious correlation between the Si/Au ratio and the electron energy is observed. With decreasing electron energy, the ratio increased significantly. This means that by reducing electron energy, information on deeper region of the surface can be obtained. These results indicate that by changing electron energies for detection, it is possible to perform non-destructive depth profiling in XAS analysis.

JAEA Reports

Design and manufacture of a testing device for the evaluation of optical elements

Shimizu, Yuichi; Yoda, Osamu; Sasuga, Tsuneo*; Teraoka, Yuden; Yokoya, Akinari; Yanagihara, Mihiro*

JAERI-Tech 2000-021, p.45 - 0, 2000/03


no abstracts in English

Journal Articles

Structure study of thin films by employing anomalous dispersion of synchrotron X-rays

Mizuki, Junichiro; Kimura, Hidekazu*

Oyo Butsuri, 68(11), p.1271 - 1274, 1999/11

no abstracts in English

Journal Articles

Materials investigation by synchrotron radiation

Mizuki, Junichiro

Kagaku Kogyo, 49(7), p.33 - 41, 1998/07

no abstracts in English

Journal Articles

Surface and interface structural studies by SR-X-rays

Mizuki, Junichiro

Zairyo Kagaku, 35(3), p.155 - 163, 1998/05

no abstracts in English

40 (Records 1-20 displayed on this page)