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Moriyama, Junichiro*; Yamaguchi, Masatake; Takakuwa, Osamu*
Materials Today Communications (Internet), 40, p.110059_1 - 110059_9, 2024/08
The present study systematically investigates hydrogen (H) solubility within multi-component alloying (Cr, Ni) interaction in Fe-Cr-Ni-based austenitic alloys, which generates a novel H-induced improvement in the strength-ductility balance that is a function of dissolved H-content. We analyzed, using first-principles calculations, H-absorption energy that is directly linked to H-solubility, in an Fe-Cr-Ni face-centered cubic (FCC) ternary system with various configurations of Cr and Ni atoms. The results we obtained clarified the effects of antagonistic interactions between Cr and Ni atoms on H-absorption energy even though both alloying elements independently reduce H-absorption energy at adjacent octahedral sites (O-sites). The present study makes it possible to comprehensively predict the H-solubility of various Fe-Cr-Ni austenitic alloys by taking account of the antagonistic Cr-Ni interaction.
Moriyama, Junichiro*; Takakuwa, Osamu*; Yamaguchi, Masatake; Ogawa, Yuhei*; Tsuzaki, Kaneaki*
Computational Materials Science, 232, p.112650_1 - 112650_11, 2024/01
Times Cited Count：6 Percentile：55.12(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.
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.
Moriyama, Junichiro*; Takakuwa, Osamu*; Ogawa, Yuhei*; Yamaguchi, Masatake; Tsuzaki, Kaneaki*
no journal, ,
no abstracts in English
Moriyama, Junichiro*; Takakuwa, Osamu*; Yamaguchi, Masatake
no journal, ,
It has recently been shown experimentally that Cr and Ni have the effect of increasing the hydrogen solubility in Fe-Cr-Ni alloys, and that alloys with high Cr/Ni ratios exhibit high hydrogen solubility characteristics. The first-principles calculations have revealed that the increase of solid solution hydrogen concentration by Cr and Ni is caused by the decrease of hydrogen dissolution energy near Cr and Ni atoms. On the other hand, there are few studies on the interaction between the effects of Cr and Ni on the solubility properties of hydrogen, respectively. In this study, this interaction was evaluated using first-principles calculations.
Moriyama, Junichiro*; Yamaguchi, Masatake; Takakuwa, Osamu*
no journal, ,
It has recently been shown experimentally that Cr and Ni have the effect of increasing the hydrogen solubility in Fe-Cr-Ni alloys, and that alloys with high Cr/Ni ratios exhibit high hydrogen solubility characteristics. The first-principles calculations have revealed that the increase of solid solution hydrogen concentration by Cr and Ni is caused by the decrease of hydrogen dissolution energy near Cr and Ni atoms. On the other hand, there are few studies on the interaction between the effects of Cr and Ni on the solubility properties of hydrogen, respectively. In this study, this interaction was evaluated using first-principles calculations.
