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Hayashi, Makoto*; Shobu, Takahisa
Residual Stress, p.100 - 132, 2021/00
Structural materials may undergo fatigue fracture or stress corrosion cracking during use. One of the causes is the residual stress generated by heat treatment and processing in the manufacturing process of structural materials. There are various methods for measuring the residual stress. This book introduces measurement techniques using ultrasonic and magnetic methods, starting with laboratory X-rays, synchrotron radiation X-rays, and neutrons. In addition, we will outline examples of measurement of residual stress due to processing and welding of various materials, measurement examples of actual machines, change behavior of residual stress due to static and repeated loads, and evaluation methods of fatigue remaining life based on the change behavior.
Watanabe, Masashi*; Yonezawa, Toshio*; Shobu, Takahisa; Shiro, Ayumi; Shoji, Tetsuo*
Corrosion, 72(9), p.1155 - 1169, 2016/09
Times Cited Count：1 Percentile：6.15(Materials Science, Multidisciplinary)Davies, A. R.*; Field, J. E.*; Takahashi, Koji; Hada, Kazuhiko
Diamond and Related Materials, 14(1), p.6 - 10, 2005/01
Times Cited Count：21 Percentile：63.34(Materials Science, Multidisciplinary)A CVD diamond is finding increased application and it is important to study its fatigue properties. The present paper describes research on a batch of di-electric grade CVD material. It was obtained that tensile strength at the nucleation side and the growth were side 690
90MPa and 28030MPa, respectively. Some samples survived at least 95% of their critical fracture stress for 10
cycles without fatiguing.
Motooka, Takafumi; Kiuchi, Kiyoshi
Corrosion, 58(8), p.703 - 709, 2002/08
Times Cited Count：11 Percentile：57.51(Materials Science, Multidisciplinary)Ti-5Ta alloy and zirconium with excellent corrosion resistance to nitric acid have been used as equipment materials in spent fuel reprocessing plants. However, zirconium has the susceptibility to stress corrosion cracking in nitric acid solutions. The fatigue crack growth rates of both metals were examined to clarify the effect of stress corrosion cracking on the fatigue crack growth in boiling 17% nitric acid. The fatigue crack growth behavior of Ti-5Ta alloy in nitric acid showed almost the same behavior as seen in air. The crack growth rate is slightly enhanced in nitric acid. The fracture surface showed the ductile striation with independence on the loading direction. On the other hand, the fatigue crack growth rate of zirconium is remarkably accelerated in nitric acid. The fatigue crack growth was affected by the cracking mode composed of the pseudo-cleavage and plastic deformation. The difference in fatigue cracking behavior on both metals in nitric acid is interpreted with the difference in a cross slip system and the corrosion resistance in nitric acid.
Motooka, Takafumi; Kiuchi, Kiyoshi
Corrosion, 58(6), p.535 - 540, 2002/06
Times Cited Count：5 Percentile：39.93(Materials Science, Multidisciplinary)The fatigue crack growth of a commercial grade zirconium has been studied in boiling nitric acid and in air at room temperature under tensile load control. The fatigue crack growth rate in air is strongly dependent on the crystallographic texture. It is interpreted based on the crystal anisotropy on mechanical strength in the hexagonal closed pack structure of zirconium. The fatigue crack growth rate in nitric acid is about four times higher than that in air. Texture is found to have an effect on the fracture path in nitric acid. Microfractography of the fracture surfaces shows that the corrosion fatigue growth has a characteristic mechanism. The fracture surface consists of a mixture of grains: some broken by pseudo-cleavage as seen in stress corrosion cracking, and the others broken by fatigue with striation as seen in air. In the low crack growth rate regime pseudo-cleavage is dominant, whereas in the high crack growth rate regime the main fracture mode is ductile fracture.
Motooka, Takafumi; Kiuchi, Kiyoshi
Materials Transactions, 43(5), p.1220 - 1224, 2002/05
Times Cited Count：2 Percentile：23.90(Materials Science, Multidisciplinary)Refractory materials such as zirconium, niobium and titanium alloys with excellent corrosion resistance in boiling nitric acid have been selected for use as structural materials of spent fuel reprocessing equipment. The fatigue crack growth rates of these materials were investigated by load control tests as a function of the stress intensity factor range in boiling 3N nitric acid and in air at room temperature. The fracture surfaces were observed by SEM. The fatigue crack growth rates of zirconium and niobium were enhanced in boiling nitric acid compared with those in air at room temperature. Acceleration effect due to corrosion fatigue was not observed in the crack growth of Ti-5Ta alloy. The fracture surfaces of Ti-5Ta alloy showed the ductile striation in both environments. On the other hand, the fracture surfaces of niobium represented the fatigue striation in air and the brittle striation due to corrosion in nitric acid. The fracture surfaces of zirconium in nitric acid showed brittle fracture and the ductile fracture related to stress corrosion cracking.
Nakahira, Masataka; Takeda, Nobukazu; Hada, Kazuhiko; Tada, Eisuke; Miya, Kenzo*; Asada, Yasuhide*
Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 7 Pages, 2002/04
The special features of Vacuum Vessel (VV) of International Thermonuclear Experimental Reactor (ITER) are complicated structure and electromagnetic load. The VV is torus shaped, double-walled structure with ribs. The electromagnetic force is not uniform. Thus the rules for axisymmetric structures and loading are not effective for ITER VV. The double ミwalled structure requires one-sided welding joints with no possibility of access from the other side. Every joints between outer wall and rib and field joints are this type. The joint between outer wall and rib is special T-joint with partial penetration. To cover these special issues on ITER VV, a new code is under development. Supporting R&Ds are planned to be material tests to obtain joint efficiency and fatigue reduction factor, UT sensitivity tests, sensitivity tests on crevice corrosion and examination-free welding for application to field joints. This paper describes the special features of ITER VV from code stand point, concept of new code and R&Ds to apply the new code to ITER VV.
Motooka, Takafumi; Kiuchi, Kiyoshi
Proceedings of the 2nd International Conference on Environment Sensitive Cracking and Corrosion Damage (ESCCD 2001), p.374 - 378, 2001/11
Refractory metals such as Zr, Nb and Ti alloys with the excellent corrosion resistance in boiling nitric acid have been selected for structural materials of spent fuel reprocessing equipment. On this study, the fatigue crack growth rate of these materials was investigated by load control tests as a function of the stress intensity in boiling nitric acid and in air at room temperature. The fracture surface was observed by scanning electron microscopy. The crack growth rate of Zr and Nb was enhanced in boiling nitric acid compared with that in air at room temperature. Acceleration effect due to corrosion fatigue was not observed in the crack growth of Ti-5Ta alloy. The fracture surfaces of Ti-5Ta alloy showed the ductile striation in both environments. On the other hand, the fracture surfaces of Nb showed the ductile striation in air and brittle striation in nitric acid. The anodic dissolution was interpreted to the acceleration factor on corrosion fatigue of Nb. The fracture surfaces of Zr in nitric acid showed both brittle and ductile fracture with fluted pattern due to SCC.
; ; Shindo, Masami; ; ; ; ; ; ; ; et al.
JAERI-M 82-062, 23 Pages, 1982/06
no abstracts in English
; Nakajima, Hajime; Kondo, Tatsuo;
Zairyo, 31(346), p.703 - 709, 1982/00
no abstracts in English
; M.Suzuki*; ; Kondo, Tatsuo
ASME J.Eng.Mater.Technol., 103(10), p.298 - 304, 1981/00
Times Cited Count：31 Percentile：89.53(Engineering, Mechanical)no abstracts in English
Kondo, Tatsuo
Boshoku Gijutsu, 26(1), p.31 - 41, 1977/01
no abstracts in English
