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Moriyama, Junichiro*; Takakuwa, Osamu*; Yamaguchi, Masatake; Ogawa, Yuhei*; Tsuzaki, Kaneaki*
Computational Materials Science, 232, p.112650_1 - 112650_11, 2024/01
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)The present study focuses on a novel hydrogen-improved strength-ductility balance in some practical Fe-Cr-Ni-based austenitic alloys, which directly depends on the solute hydrogen content. The hydrogen absorption energy of the Fe-Cr-Ni model alloys with the face-centered cubic structure was examined using first-principles calculations to verify the contribution of Cr and Ni substitutions from Fe to the hydrogen solubility in the alloys. The Cr substitution substantially reduced the hydrogen absorption energy compared to the Ni substitution, whereby the increased Cr/Ni ratio exerts higher hydrogen solubility. The propensity in the calculations coincided with the experimental results obtained previously in the practical alloys with various Cr / Ni ratios.
Onuma, Masato*; Suzuki, Junichi; Wei, F.*; Tsuzaki, Kaneaki*
Scripta Materialia, 58(2), p.142 - 145, 2008/01
Times Cited Count：69 Percentile：92.44(Nanoscience & Nanotechnology)no abstracts in English
Kaburaki, Hideo; Tsuzaki, Kaneaki*
no journal, ,
A tensile test has been performed for the martensite steel sepecimen charged with hydrogen. The results show that intergranular fracture was observed in the region when the hydrogen concentration is high. Stress and hydrogen distribution near the notch of the specimen are predicted by the finite element method using the continuum model. In order to find the cause of this fracture, a change in the cohesive strength of a simple grain boundary due to hydrogen segregation is estimated by the first principles calculation. As a result, a relative reduction of the critical applied stress for the hydrogen embrittlement test is explained well by the results of the first priciples calculation.
Moriyama, Junichiro*; Takakuwa, Osamu*; Ogawa, Yuhei*; Yamaguchi, Masatake; Tsuzaki, Kaneaki*
no journal, ,
no abstracts in English
Moriyama, Junichiro*; Takakuwa, Osamu*; Yamaguchi, Masatake; Ogawa, Yuhei*; Tsuzaki, Kaneaki*
no journal, ,
In some austenitic stainless steels (Fe-Cr-Ni basic composition), hydrogen exhibits a high solution strengthening capacity with increasing solid solution hydrogen concentration that is difficult to explain by dimensional effects. In order to understand this phenomenon, it is necessary to understand the local hydrogen concentration in addition to the average solid solution hydrogen concentration in the Fe-Cr-Ni system. Since the average solid solution hydrogen concentration depends on the amount of Cr and Ni, the interaction between these substitutional atoms and hydrogen atoms is considered to be an important factor to focus on. In this study, first-principles calculations were used to quantify the interaction between Cr and Ni atoms and hydrogen atoms, and to evaluate the average solid-solution hydrogen concentration (occupancy) and its effect on the distribution.
