Inverted-parabolic and weak strain dependencies on the critical current in practical 110 and 100 oriented REBCO tapes

Osamura, Kozo*; Machiya, Shutaro*; Kajiwara, Kentaro*; Kawasaki, Takuro; Harjo, S.; Zhang, Y.*; Fujita, Shinji*; Iijima, Yasuhiro*; Hampshire, D. P.*

AIP Advances (Internet), 9(7), p.075216_1 - 075216_11, 2019/07

https://doi.org/10.1063/1.5092248

Microstructural characterization of electrodeposited nanocrystalline nickel films by X-ray diffraction

Tanaka, Keisuke*; Koike, Yuki*; Sano, Katsuki*; Tanaka, Hiroto*; Machiya, Shutaro*; Shobu, Takahisa; Kimachi, Hirohisa*

Zairyo, 64(7), p.528 - 535, 2015/07

https://doi.org/10.2472/jsms.64.528

no abstracts in English

Residual strains in ITER conductors by neutron diffraction

Harjo, S.; Hemmi, Tsutomu; Abe, Jun; Gong, W.; Nunoya, Yoshihiko; Aizawa, Kazuya; Ito, Takayoshi*; Koizumi, Norikiyo; Machiya, Shutaro*; Osamura, Kozo*

Materials Science Forum, 777, p.84 - 91, 2014/02

https://doi.org/10.4028/www.scientific.net/MSF.777.84

Neutron diffraction measurement of internal strain in the first Japanese ITER CS conductor sample

Hemmi, Tsutomu; Harjo, S.; Nunoya, Yoshihiko; Kajitani, Hideki; Koizumi, Norikiyo; Aizawa, Kazuya; Machiya, Shutaro*; Osamura, Kozo*

Superconductor Science and Technology, 26(8), p.084002_1 - 084002_6, 2013/08

https://doi.org/10.1088/0953-2048/26/8/084002

JAEA has responsibly to procure all ITER CS conductors. Several conductor samples was fabricated and tested. From the result of the cyclic testing in first conductor sample named JACS01 and second conductor sample named JACS02, the continuous linear degradation of the current sharing temperature () was observed. To investigate the degradation, the visual inspection of JACS01 right leg was performed. As a result, the large deflection at the lower loading side (LLS) in the high field zone (HFZ) was observed. The bending strain of the strands cannot be evaluated from the only deflection obtained by a visual inspection. To evaluate the strain of strands in the conductor sample quantitatively, the neutron diffraction measurement of JACS01 left leg was performed using the engineering materials diffractometer in J-PARC. From the result, the large bending strain at the LLS in the HFZ was observed. Therefore, the degraded position in the conductor sample can be determined.

Neutron diffraction measurements of internal strain in NbSn cable-in-conduit conductors

Hemmi, Tsutomu; Harjo, S.; Ito, Takayoshi; Matsui, Kunihiro; Nunoya, Yoshihiko; Koizumi, Norikiyo; Takahashi, Yoshikazu; Nakajima, Hideo; Aizawa, Kazuya; Suzuki, Hiroshi; et al.

IEEE Transactions on Applied Superconductivity, 21(3), p.2028 - 2031, 2011/06

https://doi.org/10.1109/TASC.2010.2089770

Residual strain in conductors is caused by the difference in the coefficient of expansion between NbSn strands and the jacket over a temperature range of 5 - 923 K. The superconducting properties of strands vary significantly, depending on the strain. It is important to clarify the residual strain as part of the evaluation of superconducting performance. However, the residual strain of strands in the conductor has not been measured so far because of their complicated configuration and their location in a jacket. The engineering materials diffractometer "Takumi" in J-PARC can measure residual strain with a relative accuracy of around 0.02%, using neutron diffraction. In this study, the Takumi was applied to the measurement of residual strain in strands for the ITER TF conductor. Results indicate that the residual strain of strands in the conductor can be determined, thereby clarifying the mechanism of residual strain and its relationship to superconducting performance.

Force free strain exerted on a YBCO layer at 77 K in surround Cu stabilized YBCO coated conductors

Osamura, Kozo*; Machiya, Shutaro*; Tsuchiya, Yoshinori*; Suzuki, Hiroshi

Superconductor Science and Technology, 23(4), p.045020_1 - 045020_7, 2010/04

https://doi.org/10.1088/0953-2048/23/4/045020

The stress/strain behavior of the surround Cu stabilized YBCO coated conductors and its influence on critical current were precisely investigated. The internal strain exerted on the superconducting YBCO layer was determined at 77 K by using a neutron diffraction technique at JAEA. The initial compressive strain decreased during tensile loading and changed to a tensile component at the force free strain (A), where the internal uniaxial stress becomes zero in the YBCO layer. The A was evaluated to be 0.19-0.21% at 77 K. The critical current measurements were carried out under a uniaxial tensile load at 77 K. The strain dependence revealed a characteristic behavior, where a maximum was observed at 0.035%. Thus it was made clear that the strain at the critical current maximum does not correlate with A for YBCO coated conductors.

Strain measurements of superconducting filaments and Ag-alloy using neutron diffraction in Ag-sheathed Bi2223 tapes

Machiya, Shutaro; Osamura, Kozo*; Suzuki, Hiroshi; Shiota, Yoshinori*; Ayai, Naoki*; Hayashi, Kazuhiko*; Sato, Kenichi*

no journal, , 

In situ strain measurement was made for inner Bi2223 filaments and outer Ag alloy in the Ag-sheathed Bi2223 tapes using neutron diffraction. The residual strain and the strain response under the axial tensile loading were measured in the Ag-sheathed Bi2223 tapes stacked with 10 sheets.

A Study on residual stress measurement of forged Al alloy part with coarse grain by neutron diffraction

Saito, Toru; Terakado, Katsuyoshi*; Ishibashi, Toshihiro*; Katayanagi, Kazue*; Machiya, Shutaro; Tomota, Yo*

no journal, , 

no abstracts in English

Residual stress estimation of Ag-sheathed Bi2223 tapes using Neutron and X-ray diffraction

Machiya, Shutaro; Osamura, Kozo*; Suzuki, Hiroshi; Ayai, Naoki*; Kato, Takeshi*; Hayashi, Kazuhiko*; Sato, Kenichi*

no journal, , 

no abstracts in English

Development of asymmetric monochromator system for neutron diffraction method

Suzuki, Hiroshi; Saito, Toru; Machiya, Shutaro; Morii, Yukio

no journal, , 

Neutron Diffractometer for Residual Stress Analysis (RESA) installed in JRR-3 of JAEA has been used mainly for the stress or the strain measurement for sample of small or medium size so far. However, the experiment number of stress measurements for the large structure increases as the number of industrial applications increases in recent years. As a result, overcrowded machine time and lack of measuring time, etc. have been caused. It is necessary to develop a highly effective, highly accurate neutron stress measurement technology to solve these various problems. One of the upgrades is development of the asymmetric monochromator system. In this research, the diffraction characteristic of the silicon crystal of the asymmetric diffraction type was evaluated. As a result, the increasing rate of the diffracted intensity that had been obtained by the experiment correspond with the increasing rate calculated from the theory.