In situ neutron diffraction study of strain evolution and load partitioning during elevated temperature tensile test in HIP-Treated electron beam powder bed fusion manufactured Ti-6Al-4V

Pandian, K.*; Neikter, M.*; Ekh, M.*; Harjo, S.; Kawasaki, Takuro; Woracek, R.*; Hansson, T.*; Pederson, R.*

JOM, 77(4), p.1803 - 1815, 2025/04

https://doi.org/10.1007/s11837-025-07128-1

Quantitative evaluation of irradiated ductility degradation using the indentation technique combined with numerical experiments

Wakui, Takashi; Saito, Shigeru; Futakawa, Masatoshi

Materials, 17(23), p.5925_1 - 5925_14, 2024/12

https://doi.org/10.3390/ma17235925

The ductile properties of irradiated materials are one of the important indicators related to their structural integrity. Indentation tests are used for evaluating the ductile properties easily and rapidly. Constants in the material constitutive equation were identified via inverse analysis using the Kalman filter, such that the numerical experimental results reproduced the indentation test results. Numerical tensile experiments were conducted using stress-strain curves with the identified constants to obtain nominal stress-strain curves. Furthermore, two methods were proposed for evaluating the total elongation. Evaluated minimum total elongation was 10 %. The evaluation results of ion-irradiated materials were similar to the tensile test results of irradiated materials.

Formulation of material property formula for calculation of damage in reactor pressure vessel during accident evaluation

Shimomura, Kenta; Yamashita, Takuya; Nagae, Yuji

Proceedings of 11th European Review Meeting on Severe Accident Research Conference (ERMSAR 2024) (Internet), 12 Pages, 2024/05

https://doi.org/10.5445/IR/1000174165/v2

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.