Effects of loading direction on the anisotropic tensile properties of duplex stainless steels based on phase strains obtained by in situ neutron diffraction experiments

Matsushita, Akira*; Tsuchida, Noriyuki*; Ishimaru, Eiichiro*; Hirakawa, Naoki*; Gong, W.; Harjo, S.

Journal of Materials Engineering and Performance, 10 Pages, 2023/06

https://doi.org/10.1007/s11665-023-08424-0

Tensile overload-induced texture effects on the fatigue resistance of a CoCrFeMnNi high-entropy alloy

Lam, T.-N.*; Chin, H.-H.*; Zhang, X.*; Feng, R.*; Wang, H.*; Chiang, C.-Y.*; Lee, S. Y.*; Kawasaki, Takuro; Harjo, S.; Liaw, P. K.*; et al.

Acta Materialia, 245, p.118585_1 - 118585_9, 2023/02

https://doi.org/10.1016/j.actamat.2022.118585

Microstructure and texture evolution and ring-tensile properties of recrystallized FeCrAl ODS cladding tubes

Aghamiri, S. M. S.*; Sowa, Takashi*; Ukai, Shigeharu*; Ono, Naoko*; Sakamoto, Kan*; Yamashita, Shinichiro

Materials Science & Engineering A, 771, p.138636_1 - 138636_12, 2020/01

https://doi.org/10.1016/j.msea.2019.138636

Oxide dispersion strengthened (ODS) FeCrAl ferritic steels are being developed as potential accident tolerance fuel cladding materials for the light water reactors (LWRs) due to significant improvement in steam oxidation by alumina forming scale and good mechanical properties up to high temperatures. In this study, the microstructural characteristics and tensile properties of the two FeCrAl ODS cladding tubes with different extrusion temperatures of 1100C and 1150C were investigated during processing conditions. While the hot extruded sample showed micron sized elongated grains with strong -fiber in 110 texture, cold pilger rolling process change the microstructure to submicron/micron size grain structure along with texture evolution to both -fiber (110 texture) and -fiber ({111} texture) via crystalline rotations. Subsequently, final annealing resulted in evolution of microstructure to large grain recrystallized structure starting at recrystallization temperature of 810-850C. Two distinct texture development happened in recrystallized cladding tubes, i.e., only large elongated grains of (110) 211 texture following extrusion temperature of 1100C; and two texture components of (110) 211 and {111} 112 following higher extrusion temperature of 1150C. The different texture development and retarding of recrystallization progress in 1100C-extruded cladding tubes were attributed to higher distribution of oxide particles.

Influence of temperature histories during reactor startup periods on microstructural evolution and mechanical properties of austenitic stainless steel irradiated with neutrons

Kasahara, Shigeki; Kitsunai, Yuji*; Chimi, Yasuhiro; Chatani, Kazuhiro*; Koshiishi, Masato*; Nishiyama, Yutaka

Journal of Nuclear Materials, 480, p.386 - 392, 2016/11

https://doi.org/10.1016/j.jnucmat.2016.06.017

This paper addresses influence of two different temperature profiles during startup periods in the Japan Materials Testing Reactor and a boiling water reactor upon microstructural evolution and mechanical properties of austenitic stainless steel irradiated with neutrons to about 1 dpa and 3 dpa. Tensile tests at 290C and Vickers hardness tests at room temperature were carried out, and their microstructures were observed by FEG-TEM. Influence of difference in the temperature profiles was observed obviously in interstitial cluster formation, in particular, growth of Frank loops. The influence was also found certainly in loss of strain hardening capacity and ductility, although the influence on the yield strength and the Vickers hardness was not clearly observed. As a result, Frank loops, which were observed in austenitic stainless steel irradiated at doses of 1 dpa or more, were considered to contribute to deformation of the austenitic stainless steel.

Residual stress evaluation of butt weld sample of high tensile strength steel using neutron diffraction

Suzuki, Hiroshi; Holden, T. M.*; Moriai, Atsushi; Minakawa, Nobuaki*; Morii, Yukio

Zairyo, 54(7), p.685 - 691, 2005/07

https://doi.org/10.2472/jsms.54.685

no abstracts in English

Tensile and fatigue strength of free-standing CVD diamond

Davies, A. R.*; Field, J. E.*; Takahashi, Koji; Hada, Kazuhiko

Diamond and Related Materials, 14(1), p.6 - 10, 2005/01

https://doi.org/10.1016/j.diamond.2004.06.015

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 69090MPa and 28030MPa, respectively. Some samples survived at least 95% of their critical fracture stress for 10 cycles without fatiguing.

Post irradiation plastic properties of F82H derived from the instrumented tensile tests

Taguchi, Tomitsugu; Jitsukawa, Shiro; Sato, Michitaka*; Matsukawa, Shingo*; Wakai, Eiichi; Shiba, Kiyoyuki

Journal of Nuclear Materials, 335(3), p.457 - 461, 2004/12

https://doi.org/10.1016/j.jnucmat.2004.08.001

F82H (Fe-8Cr-2W) and its variant doped with 2%Ni were irradiated up to 20 dpa at 300C in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. Post irradiation tensile testing was performed at room temperature. During testing, the images of the specimens including the necked region were continuously recorded. Tests on cold worked material were also carried out for comparison. From the load-displacement curves and the strain distributions obtained from the images, flow stress levels and strain hardening behavior was evaluated. A preliminary constitutive equation for the plastic deformation of irradiated F82H is presented. The results suggest that the irradiation mainly causes defect-induced hardening while it did not strongly affect strain hardening at the same flow stress level for F82H irradiated at 300C. The strain hardening of Ni doped specimens was, however, strongly affected by irradiation. Results provide basics to determine allowable stress levels at temperatures below 400C.

Characterizations of heavy ion irradiated PET membranes

Takahashi, Shuichi*; Yoshida, Masaru; Asano, Masaharu; Notomi, Mitsuo*; Nakagawa,Tsutomu*

Nuclear Instruments and Methods in Physics Research B, 217(3), p.435 - 441, 2004/05

https://doi.org/10.1016/j.nimb.2003.10.017

Various characterization were used to study the effect of heavy ion irradiation on a poly(ethylen terephthalate)(PET) membrane. My study was followed using some dynamic and thermal measurements with the aim to undestand the chemical change in the material by heavy ion irradiation. The anyalyese included DMA, tensile measurement, DSC and micro-FT-IR. The overall structure change in the PET polymer was investigated as a function of the Xe ion fluence in the range from 310 to 310ions/cm. Based on some mechanical measurements such as the tensile analysis and dynamic test, the heavy ion irradiated PET membranes exhibited a significant change in cross-linking. I believe that the secondary electron induced by collision between the irradiated ion and the constituent atoms of the membrane material form the cross-linking. The polymer chain scission and structure degradations are expected to result at higher ion fluence. Also, a slight change in the structure such as amorphization has been shown by DSC and the micro-FT-IR test.

Development of an extensive database of mechanical and physical properties for reduced-activation martensitic steel F82H

Jitsukawa, Shiro; Tamura, Manabu*; Van der Schaaf, B.*; Klueh, R. L.*; Alamo, A.*; Petersen, C.*; Schirra, M.*; Spaetig, P.*; Odette, G. R.*; Tavassoli, A. A.*; et al.

Journal of Nuclear Materials, 307-311(Part1), p.179 - 186, 2002/12

https://doi.org/10.1016/S0022-3115(02)01075-9

Reduced activation ferritic/martensitic steel is the primary candidate structural material for ITER Test Blanket Modules and DEMOnstration fusion reactor because of its excellent dimensional stability under irradiation and lower residual activity as compared with the Ni bearing steels such as the austenitic stainless steels. In this paper, microstructural features, tensile, fracture toughness, creep and fatigue properties of a reduced activation martensitic steel F82H (8Cr-2W-0.04Ta-0.1C) are reported before and after irradiation, in addition to the design concept used for development of this alloy. A large number of collaborative test results including those generated under the IEA working group implementing agreements are collected and are used to evaluate the feasibility of use of F82H steel as one of the reference alloys. The effect of metallurgical variables on the irradiation hardening is reviewed and compared with the results obtained from irradiation experiments.

Evaluation of in-pile and out-of-pile stress relaxation in 316L stainless steel under uniaxial loading

Kaji, Yoshiyuki; Miwa, Yukio; Tsukada, Takashi; Kikuchi, Masahiko; Kita, Satoshi; Yonekawa, Minoru; Nakano, Junichi; Tsuji, Hirokazu; Nakajima, Hajime

Journal of Nuclear Materials, 307-311(Part1), p.331 - 334, 2002/12

https://doi.org/10.1016/S0022-3115(02)01204-7

Irradiation assisted stress corrosion cracking (IASCC) caused by simultaneous effects of neutron irradiation and high temperature water environments has been pointed out as one of the major concerns of in-core structural materials not only for the light water reactors (LWRs) but also for the water-cooled fusion reactor. It is necessary to evaluate precisely stress condition under irradiation environment, because stress is one of key factors on IASCC. Stress relaxation of tensile type specimens under fast neutron irradiation at 288C has been studied for type 316L stainless steel in Japan Materials Testing Reactor (JMTR). This paper describes the in-pile and out-of-pile stress-relaxation test results of tensile type specimens for type 316L stainless steel as compared with the literature data by Foster, which were mainly obtained by bent beam specimens. Moreover these experimental results were compared with the analytical ones by using Nakagawa's model.