Relaxation behavior of laser-peening residual stress under tensile loading investigated by X-ray and neutron diffraction

Akita, Koichi; Hayashi, Kengo*; Takeda, Kazuya*; Sano, Yuji*; Suzuki, Hiroshi; Moriai, Atsushi; Oya, Shinichi*

Mechanical Engineering Journal (Internet), 1(4), p.SMM0029_1 - SMM0029_8, 2014/08

https://doi.org/10.1299/mej.2014smm0029

Compressive residual stresses induced by peening techniques improve the strength properties of steels, such as fatigue and stress corrosion cracking. However, the compressive residual stress might be reduced owing to thermal and mechanical loading in-service. In this study, the behavior of surface and internal residual stresses of a laser-peened ferritic steel under quasi-static tensile loading was investigated by X-ray and neutron diffraction. The complementary use of these diffraction techniques provided decisive experimental evidence for elucidating the relaxation process. The critical applied stress of peened samples subjected to a tensile loading can be estimated from the von Misses yield criterion with the maximum tensile residual stress inside the sample.

Bulk texture evaluation by angle dispersive neutron diffraction

Xu, P. G.; Akita, Koichi; Suzuki, Hiroshi; Moriai, Atsushi; Suzuki, Tetsuya*; Yukutake, Eitaro*

Nihon Zairyo Gakkai Dai-46-Kai X Sen Zairyo Kyodo Ni Kansuru Shimpojiumu Koen Rombunshu, p.24 - 27, 2012/07

Aspire to become TAKUMI; TAKUMI present status and research topics

Harjo, S.; Aizawa, Kazuya; Ito, Takayoshi; Arima, Hiroshi; Abe, Jun; Moriai, Atsushi; Sakasai, Kaoru; Nakamura, Tatsuya; Nakatani, Takeshi; Iwahashi, Takaaki; et al.

Materials Science Forum, 652, p.99 - 104, 2010/09

https://doi.org/10.4028/www.scientific.net/MSF.652.99

The construction of The Engineering Materials Diffractometer, TAKUMI of J-PARC has been finished on March 2009, and the commissioning has been started from September 2008 being parallel with the final stage of the construction. In the commissioning, after checking the validity and the stability of the detectors and the data acquisition system, we checked powder diffraction data of a 2 mm diameter of annealed piano wire with combination of beam collimation (high resolution mode), and confirmed that resolution / of less than 0.2% can be achieved. We also reports preliminary results from researches using TAKUMI.

A Cubic-anvil high-pressure device for pulsed neutron powder diffraction

Abe, Jun; Arakawa, Masashi*; Hattori, Takanori; Arima, Hiroshi; Kagi, Hiroyuki; Komatsu, Kazuki*; Sano, Asami; Uwatoko, Yoshiya*; Matsubayashi, Kazuyuki*; Harjo, S.; et al.

Review of Scientific Instruments, 81(4), p.043910_1 - 043910_5, 2010/04

https://doi.org/10.1063/1.3384238

A compact cubic-anvil high-pressure device was developed for in situ neutron powder diffraction studies. In this device, a cubic shaped pressure medium is compressed by six anvils, and neutron beam pass through gaps between the anvils. The first high-pressure experiment using this device was conducted at J-PARC and clearly showed the neutron diffraction patterns of Pb. Combining the cubic-anvil high-pressure device with a pulsed neutron source will prove to be a useful tool for neutron diffraction experiments.

Measurement of residual stress on a unidirectional solidified AlO/YAG eutectic composite using synchrotron and neutron diffraction

Suzuki, Hiroshi; Waku, Yoshiharu*; Nakagawa, Narihito*; Akita, Koichi*; Moriai, Atsushi; Morii, Yukio

Journal of Neutron Research, 15(2), p.113 - 120, 2007/06

https://doi.org/10.1080/10238160701372471

The residual stress in only YAG phase was measured on the surface of the AlO-YAlO(YAG) eutectic composite(AlO/YAG MGC) using the low energy synchrotron X-rays. The residual stresses in plane stress condition were significantly different between top and side surfaces of the specimen. Therefore, an anisotropic triaxial residual stress probably exists within the MGC. The residual stress within the MGC was also measured using a neutron diffraction. The residual stress in the YAG phase rose from compression in the solidification direction to tension in perpendicular direction. The residual stress in the AlO phase was anisotropic compression and there was no tension in all directions. This anisotropic residual stress could be explained by the crystallographic anisotropy of thermal expansion in the AlO phase. However, both phase stresses were not balanced, so that it is expected that there would be the stress distribution in MGC sample used in this study.

A New neutron reflectometer SUIREN at JRR-3

Yamazaki, Dai; Soyama, Kazuhiko; Moriai, Atsushi; Tamura, Itaru; Nakamura, Kiyoshi

Hamon, 16(3), p.174 - 176, 2006/07

https://doi.org/10.5611/hamon.16.174

no abstracts in English

Design of engineering diffractometer at J-PARC

Harjo, S.; Moriai, Atsushi; Torii, Shuki; Suzuki, Hiroshi; Suzuya, Kentaro; Morii, Yukio; Arai, Masatoshi; Tomota, Yo*; Akita, Koichi*; Akiniwa, Yoshiaki*

Materials Science Forum, 524-525, p.199 - 204, 2006/00

An engineering diffractometer designed to solve many problems in materials science and engineering including investigations of stresses and crystallographic structures within engineering components is now being developed at J-PARC project. This instrument views a decoupled-poisoned liquid H moderator, and the primary and the secondary flight paths are 40 m and 2.0 m, respectively, for 90 degree scattering detector banks. The optimization of this instrument has been performed with a Monte Carlo simulation, and an appropriate resolution of less than 0.2 % in d/d has been confirmed. A prototyped radial collimator to define a gauge width of 1 mm has been designed and manufactured. From performance tests conducted at the neutron diffractometer for residual stress analysis RESA, the normal distribution with a full width at half maximum of 1.0 mm was obtained in a good agreement with the simulation.

Application of neutron stress measurement method without stress-free lattice constant to practical material

Suzuki, Hiroshi; Moriai, Atsushi; Minakawa, Nobuaki*; Morii, Yukio

Zairyo, 54(3), p.339 - 345, 2005/03

https://doi.org/10.2472/jsms.54.339

In a conventional method of a neutron stress measurement, it is required to know the stress-free lattice constant accurately. A new stress measurement method, which does not need the lattice constant of the strain-free material, was applied to evaluate the residual stress distributions in welded sample. The lattice constant distribution which was measured by using our proposed method showed an increase as close to the weld zone, and the absolute value of the lattice constant almost agreed with the lattice constant which was measured using coupons cut from welded sample. Therefore, it is possible to predict the lattice constant by using our proposed method. The residual stress distributions were evaluated by using conventional method and our proposed method. As a result, the residual stress distributions decided by our proposed method almost agreed with those measured by conventional method. This proposed method can be applied to determination of the residual stress states in the samples with the complex residual stress states.

Performance of upgraded thermal neutron guides with supermirrors at JRR-3

Tamura, Itaru; Suzuki, Masatoshi; Hazawa, Tomoya; Moriai, Atsushi; Hori, Naohiko; Sasajima, Fumio; Soyama, Kazuhiko

Nuclear Instruments and Methods in Physics Research A, 529(1-3), p.234 - 237, 2004/08

https://doi.org/10.1016/j.nima.2004.04.162

Thermal neutron guides at JRR-3 reactor have been upgraded from Nickel mirrors to Ni/Ti multilayer supermirrors. We performed the characteristics experiment of neutron beams transmitted through supermirror neutron guides. Neutron fluxes at the end of the thermal neutron guides were measured by the gold foil activation method on March 2003. We have confirmed that neutron fluxes at the end of thermal neutron guide increases by 6 times. The neutron spectra were also measured at the end of the thermal neutron guides by the time-of-flight method. The wavelength range for the neutron beam is extended and the shorter wavelength neutrons, which had been filtered by the characteristics of curved neutron guides before upgrade, were observed. In this paper, we have performed several Monte Carlo simulation codes using the McStas package in the consideration of the performance of fabricated supermirrors and its alignment errors for the purpose of estimation of instruments performance. We discuss the comparison of the experimental results with results of simulation.

Distribution of internal stress by a shink-fit for the aluminum ring and plug

Minakawa, Nobuaki; Morii, Yukio; Moriai, Atsushi; Otomo, Akitoshi; Kikuchi, Kenji

Journal of the Physical Society of Japan, Vol.70, Supplement A, p.517 - 519, 2001/05

no abstracts in English