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Wakui, Takashi; Yamasaki, Kazuhiko*; Futakawa, Masatoshi
Jikken Rikigaku, 22(2), p.96 - 104, 2022/06
Pulsed laser irradiation and indentation tests on radiation shielding glasses and a lead-free glass were carried out. The size of irradiation damage of the glass with high lead content was larger than that with low content. The micro plastic behavior of glasses was quantitatively determined using the inverse analyses based on indentation results. Flow stress decreased with an increase of lead content and that in irradiated area was lower than that in unirradiated area. On the other hand, plastic flow resistance increased with an increase of the lead content and that in irradiated area was higher than that in unirradiated area. Fracture energy and critical size of plastic zone around tip of crack in unirradiated and irradiated areas were calculated based on experimental results including constants evaluated using the inverse analysis. These values decreased with an increase of the lead content and these values in irradiated area were lower than that in unirradiated area.
Futakawa, Masatoshi; Kubo, Shinji; Wakui, Takashi*; Onuki, Kaoru; Shimizu, Saburo; Yamaguchi, Akihisa*
Jikken Rikigaku, 3(2), p.109 - 114, 2003/06
Micro-indentation technique was applied to evaluate the mechanical properties of corroded surface layers of Ni-alloy, 316SS, Ti and Ta, which were exposed into the corrosive gaseous environment consisting of HI+I
+HO+H. The corrosion condition was chosen so as to simulate one of the environments in the thermochemical hydrogen production, IS process, where the degradation due to the corrosion attack by HI and the hydrogen embrittlement is a key issue from the viewpoint of material integrity. The micro-indentation tests using a spherical indenter and the inverse analysis with Kalman filter were performed to quantitatively estimate material constants of corroded surface layer. Ni-alloy exhibited good corrosion resistance and Ta was remarkably influenced by the hydrogen embrittlement.
Naoe, Takashi*; Futakawa, Masatoshi; Wakui, Takashi*; Kogawa, Hiroyuki
Nihon Kikai Gakkai Kanto Shibu Ibaraki Koenkai (2002) Koen Rombunshu, p.3 - 4, 2002/09
no abstracts in English
Futakawa, Masatoshi; Wakui, Takashi*; Steinbrech, R. W.*; Tanabe, Yuji*; Hara, Toshiaki*
Nihon Kikai Gakkai Rombunshu, A, 66(646), p.152 - 158, 2000/06
no abstracts in English
Futakawa, Masatoshi; Wakui, Takashi*; Ioka, Ikuo; Eto, Motokuni
Journal of the European Ceramic Society, 20(8), p.1135 - 1143, 2000/05
Times Cited Count：5 Percentile：44.86(Materials Science, Ceramics)no abstracts in English
Wakui, Takashi*; Futakawa, Masatoshi; Tanabe, Yuji*; Eto, Motokuni
Nihon Kikai Gakkai Rombunshu, A, 65(640), p.15 - 20, 1999/12
no abstracts in English
*; Futakawa, Masatoshi; Ioka, Ikuo; Onuki, Kaoru; Shimizu, Saburo; Eto, Motokuni; Oku, Tatsuo*; *
Zairyo, 48(7), p.746 - 752, 1999/07
no abstracts in English
Wakui, Takashi; Yamasaki, Kazuhiko*; Futakawa, Masatoshi
no journal, ,
Pulsed Nd:YAG laser was irradiated to two radiation shielding glasses with the different lead content and a lead-free glass. Although no irradiation damage of the lead-free glass was visually confirmed in the laser irradiation condition of this study, the irradiation damage in the lead glasses could be recognized and the lead glass with the high lead content tends to cause the higher irradiation damage. Vickers hardness, elastic modulus and fracture toughness were evaluated by indentation technique with a Vickers indenter were 82-75%, 90-80% and 71-65% of the lead-free glass, respectively. The yield stresses evaluated by the inverse analysis using Kalman's filter based on load-depth curve obtained by the indentation technique with a spherical indenter were 87-67% of the lead-free glass. The yield stress of the irradiation damage area of the lead glass with the low lead content decreased to 74% of unirradiated area.
Wakui, Takashi; Saito, Shigeru; Wakai, Eiichi; Sakai, Tomoki*; Mori, Kotaro*; Futakawa, Masatoshi
no journal, ,
One of dominant factors to determine the lifetime of the mercury target in J-PARC is the radiation damage. Authors suggested the tensile properties evaluation technique from numerical tensile tests using material properties estimated from inverse analyses on indentation tests. The technique was applied to ion-irradiated materials, and the validity of the technique was investigated by comparing the result with results of the PIE on the targets of SNS. By conducting indentation tests on samples cut out from used targets, it is expected that the residual lifetime estimation can be conducted considering various effects; fatigue, temperature, LME, etc. superimposed on the radiation damage from evaluating hardness and tensile properties obtained by the technique. The technique and comparison results will be discussed.
Wakui, Takashi; Saito, Shigeru; Futakawa, Masatoshi; Sakai, Tomoki*; Mori, Kotaro*
no journal, ,
One of dominant factors to determine the lifetime of the structural components used under high irradiation environment is radiation damage. The indentation test will be applied to understand the degradation in mechanical properties. In this study, the technique evaluating mechanical properties from the combination of the indentation test with inverse analysis and the numerical tensile experiment is proposed. In order to confirm that this technique can evaluate changes in mechanical properties, it was applied to ion irradiated 316L stainless steels. The numerical model consists of multi layers whose mechanical properties are dependent on the DPA distribution. The material constants of each layer were identified. The numerical tensile experiments were conducted by using identified material constants. These results are compared with the PIE results of SNS. As the results, it was confirmed that this technique is effective to evaluate the mechanical property degradation due to irradiation.
Wakui, Takashi; Saito, Shigeru; Yamasaki, Kazuhiko*; Sakai, Tomoki*; Mori, Kotaro*; 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. Ion irradiation is a technique for simulating radiation damage, but the damage area is limited to the very surface layer. Therefore, we propose a mechanical property evaluation technique using an inverse analysis combining a Kalman filter and numerical experiments to the load-depth curve. As a result, changes in the mechanical properties due to ion irradiation were detected and it was confirmed that this evaluation technique was very effectiveness. In addition, the technique was applied to lead glass, and it was clarified that the microplastic behavior of glasses can be evaluated quantitatively.
