A Study on stress measurement of weld part using double exposure method

Suzuki, Kenji*; Kura, Komoe*; Miura, Yasufumi*; Shiro, Ayumi*; Toyokawa, Hidenori*; Saji, Choji*; Kajiwara, Kentaro*; Shobu, Takahisa

Zairyo, 71(12), p.1005 - 1012, 2022/12

https://doi.org/10.2472/jsms.71.1005

This paper describes a stress measurement from a welded part of an austenitic stainless steel using synchrotron X-rays. Difficulty measuring the X-ray stress of the welded part is caused by the broadening of the diffraction spot in the radial and circumferential directions. The bending strains of the rectangular bar made of the welded part were measured using synchrotron white X-rays and the double exposure method. To improve the energy resolution, monochromatic synchrotron X-ray of 70 keV was used. The diffraction pattern showed the sharp arc like a pattern from texture material. The diffraction profile was obtained from the integral of the diffraction intensity in the direction of the circumference. The diffraction angle was determined using the double exposure method. As a result, the distribution of the residual stresses of the welded part could be measured.

Internal residual stress evaluation of bearing balls for automobile parts

Miyakawa, Susumu*; Ito, Toshimasa*; Iwahori, Keisuke*; Aoyama, Yoshihiko*; Kubo, Ryosuke*; Murata, Shinji*; Shobu, Takahisa; Shiro, Ayumi*; Kajiwara, Kentaro*

Zairyo, 69(4), p.308 - 314, 2020/04

https://doi.org/10.2472/jsms.69.308

White etching area which looks white with nital corrosive liquid may be recognized at the flaking part of a rolling bearing on which high contact stress of several GPa is applied repeatedly. Up to now, studies of white etching area of a ball have been less than studies of white etching area of inner and outer rings. In this study, as part of the flaking mechanism explication with white etching area of a ball, internal residual stress distributions of ball by using high energy white X-ray of SPring-8 (A method) and laboratorial X-ray measurement equipment (B method) were investigated. The former was modified by surface residual stress according to B method. The latter was modified by releasing stress in the form of electrolytic polishing. The results showed modified residual stress distributions almost agree qualitatively.

Development of CdTe pixel detectors combined with an aluminum Schottky diode sensor and photon-counting ASICs

Toyokawa, Hidenori*; Saji, Choji*; Kawase, Morihiro*; Wu, S.*; Hurukawa, Yukihito*; Kajiwara, Kentaro*; Sato, Masugu*; Hirono, Toko*; Shiro, Ayumi*; Shobu, Takahisa; et al.

Journal of Instrumentation (Internet), 12(1), p.C01044_1 - C01044_7, 2017/01

https://doi.org/10.1088/1748-0221/12/01/C01044

We have been developing CdTe pixel detectors combined with a Schottky diode sensor and photon-counting ASICs. The hybrid pixel detector was designed with a pixel size of 200 micro-meter by 200 micro-meter and an area of 19 mm by 20 mm or 38.2 mm by 40.2 mm. The photon-counting ASIC, SP8-04F10K, has a preamplifier, a shaper, 3-level window-type discriminators and a 24-bits counter in each pixel. The single-chip detector with 100 by 95 pixels successfully operated with a photon-counting mode selecting X-ray energy with the window comparator and stable operation was realized at 20C. We have performed a feasibility study for a white X-ray microbeam experiment. Laue diffraction patterns were measured during the scan of the irradiated position in a silicon steel sample. The grain boundaries were identified by using the differentials between adjacent images at each position.

Spin-electricity conversion induced by spin injection into topological insulators

Shiomi, Yuki*; Nomura, Kentaro*; Kajiwara, Yosuke*; Eto, Kazuma*; Novak, M.*; Segawa, Koji*; Ando, Yoichi*; Saito, Eiji

Physical Review Letters, 113(19), p.196601_1 - 196601_5, 2014/11

https://doi.org/10.1103/PhysRevLett.113.196601

Evaluation of ductile damage in aluminum single crystal with prior activity of single slip system under tensile loading

Shibano, Junichi*; Kajiwara, Kentaro*; Tsukamoto, Takuya*; Kawai, Hirokazu*; Miura, Setsuo*; Zhang, S.*; Shobu, Takahisa

Zairyo, 63(7), p.533 - 538, 2014/07

https://doi.org/10.2472/jsms.63.533

A ductile damage progress of an aluminum single crystal with the prior activity of the single slip system under tensile loading was verified by a profile analysis using white X-ray obtained in BL28B2 beam line of SPring-8. In profile analysis, an instrumental function was defined in consideration both of a divergence by slits and a response function peculiar to the energy dispersive method. As a result, dislocation density increased as ductile damage progressed, but it was relatively low near the notch. The influence of a release of the strain energy by a ductile damage progress was expected. The characteristics of ductile damage progress near the notch of the aluminum single crystal with a prior activity of a single slip system under the tensile loading were clarified from the distribution of dislocation density.

Study on evaluation of ductile damage of aluminum single crystal using synchrotron white X-ray

Shibano, Junichi*; Kiso, Minoru*; Kajiwara, Kentaro*; Shobu, Takahisa; Miura, Setsuo*; Kobayashi, Michiaki*

Zairyo, 62(7), p.443 - 450, 2013/07

https://doi.org/10.2472/jsms.62.443

The ductile damage progress of the FCC single crystal was verified by the profile analysis using the white X-ray obtained in BL28B2 beam-line of SPring-8. In this study, an aluminum single crystal of the purity 6N was used as a specimen prepared in the I-type geometry for tensile test. The notch was introduced into one side of the center of a parallel part of the specimen by wire electric discharge machining. White X-ray, which has 200 microns in height and 100 microns in width, was incident into the specimen on the Bragg angle of 3 in the horizontal plane using energy dispersive X-ray diffraction technique. As a result, in 1.1% of applied strain, increase of the lattice strain was observed in the direction of about 45 of slant from the notch bottom. In 2.2% of applied strain, the lattice strain reduced in the direction of about 45 of slant from the notch bottom. Non-uniform strain and dislocation density decreased similarly.

Observation of internal crack of steel bar by computed tomography and strain mapping near its tip using synchrotron white X-ray

Shibano, Junichi*; Kiriyama, Koji; Kajiwara, Kentaro*; Shobu, Takahisa; Suzuki, Kenji*; Arai, Takayuki*; Miura, Setsuo*; Kobayashi, Michiaki*

Zairyo, 58(7), p.596 - 602, 2009/07

https://doi.org/10.2472/jsms.58.596

Measurement of internal strain in materials using high energy white X-ray at SPring-8

Shibano, Junichi*; Shobu, Takahisa; Suzuki, Kenji*; Kiriyama, Koji; Kajiwara, Kentaro*; Kaneko, Hiroshi; Kobayashi, Michiaki*

Materials Science Forum, 571-572, p.267 - 270, 2008/00

Nondestructive evaluation and 3-D imaging of impact damage in CFRP/Ti fibre-metal laminates using synchrotron radiation laminography

Nakatani, Hayato*; Kajiwara, Kentaro*; Akita, Koichi; Ogihara, Shinji*

no journal, , 

Fibre-Metal Laminates (FMLs) are hybrid materials that consist of thin layers of metal and fibre-reinforced polymer, and have already been applied several aircraft. It is well-known that there is a difficulty in non-destructive assessment of damage in FMLs using laboratory radiography or X-ray computed tomography since FMLs have laminate structure of materials with different X-ray absorption coefficient. Synchrotron radiation laminography at SPring-8 in Japan is employed to assess low velocity impact damage in CFRP/Ti laminates as FMLs. It is verified that how each damage mode, such as crack in titanium layer, fibre break, matrix cracking, interlaminar delamination in CFRP layers and interfacial debonding between CFRP and titanium layers, can be observed in obtained reconstructed slice images. Three-dimensional imaging of the low velocity impact damage is also demonstrated by stacking the reconstructed slice images, and that is to our knowledge a novel result.

Computerized tomography of fatigue cracks in steel material using synchrotron radiation white X-rays

Kiriyama, Koji; Shibano, Junichi*; Kajiwara, Kentaro*; Shobu, Takahisa; Suzuki, Kenji*; Arai, Takayuki*; Miura, Setsuo*; Kobayashi, Michiaki*

no journal, , 

Residual stress measurement and fractographycal study of cracks are important to understand SCC (Stress Corrosion Cracking) process. In this study, CT (Computerized Tomography) imaging of steel material (alpha-Fe) have performed at BL28B2 at SPring-8. The result showed that artificial crack in the sample was clearly measured by CT, and CT are very effective tool to measure an inner state of steel material.