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Sakasegawa, Hideo; Nakajima, Motoki*; Kato, Taichiro*; Nozawa, Takashi*; Ando, Masami*
Materials Today Communications (Internet), 40, p.109659_1 - 109659_8, 2024/08
Times Cited Count：1 Percentile：8.69(Materials Science, Multidisciplinary)Nanometric oxide particles play an important role in improving the creep property of Oxide Dispersion Strengthened (ODS) steels. In our previous research, we examined a microstructural feature known as prior particle boundary (PPB). PPB refers to the surface of mechanically alloyed (MA) powders before consolidation. We revealed that the ODS steel with fine PPBs produced from smaller MA powders, exhibited shorter creep rupture times, compared to that with coarse PPBs produced from larger MA powders. The size of MA powders had an impact on the creep property. In this study, we examined the shape of MA powders, which were non-spherical shapes. Such shapes have the potential to induce anisotropic creep behavior. We conducted small punch creep tests on specimens with two different orientations to study the possible anisotropy. The results revealed that the creep rupture times varied depending on the orientation of specimen, thus indicating anisotropic creep property.
Onizawa, Kunio; Suzuki, Masahide
ISIJ International, 37(8), p.821 - 828, 1997/08
Times Cited Count：4 Percentile：39.98(Metallurgy & Metallurgical Engineering)no abstracts in English
Ishihara, Masahiro; Iyoku, Tatsuo; Shiozawa, Shusaku;
Transactions of the 13th Int. Conf. on Structural Mechanics in Reactor Technology (SMiRT),Vol. I, 0, p.575 - 580, 1995/00
no abstracts in English
Shimizu, Katsusuke*; ; Koizumi, Koichi; ; Nishio, Satoshi; Sasaki, Takashi*; Tada, Eisuke
JAERI-M 92-135, 139 Pages, 1992/09
no abstracts in English
Wakui, Takashi; Takagishi, Yoichi*; Futakawa, Masatoshi
no journal, ,
Irradiation damage due to protons and neutrons reduces ductility in the mercury target vessel of J-PARC. The radiation damage is one of the factors that determine the lifetime. The evaluation of the irradiation damage is extremely important for long-term operation at high beam power. A simple and rapid indentation technique is investigated in order to evaluate mechanical properties. A mechanical property evaluation technique was proposed that applied inverse analysis to test results, combining a Kalman filter and numerical experiments. However, the dependency of evaluation results on initial values was an issue. We proposed a new evaluation method that incorporates a one-dimensional simplified numerical model based on Hertz contact theory into Bayesian inference and introduces a method for quickly evaluating the initial values of parameters, and confirmed the effectiveness of this evaluation technology by applying it to actual materials.
Yoshikawa, Keisuke*; Wakui, Takashi; Saito, Shigeru; Mori, Kotaro*; Futakawa, Masatoshi
no journal, ,
Instrumented indentation testing, which can be conducted in a simple and rapid manner, has been widely employed for the evaluation of mechanical properties in small-scale regions. The authors have focused on the indentation load depth curves and have previously evaluated material properties through inverse analysis. Moreover, since the geometry of the residual impression formed during indentation also depends on the mechanical properties of the material, it may provide additional useful information for property evaluation. In this study, particular attention is given to the pile-up geometry of the indentation. Using numerical simulations, the relationship between the pile-up morphology and mechanical properties is investigated, and the potential improvement in evaluation accuracy through the incorporation of indentation shape information is examined.
