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Ebihara, Kenichi; Sugiyama, Yuri*; Matsumoto, Ryosuke*; Takai, Kenichi*; Suzudo, Tomoaki
Metallurgical and Materials Transactions A, 52(1), p.257 - 269, 2021/01
Times Cited Count：9 Percentile：51.51(Materials Science, Multidisciplinary)We simulated the thermal desorption spectra of a small-size iron specimen to which was applied during charging with hydrogen atoms using a model incorporating the behavior of vacancies and vacancy clusters. The model considered up to vacancy clusters 
, which is composed of nine vacancies and employed the parameters based on atomistic calculations, including the H trapping energy of vacancies and vacancy clusters that we estimated using the molecular static calculation. As a result, we revealed that the model could, on the whole, reproduced the experimental spectra except two characteristic differences, and also the dependence of the spectra on the aging temperature. By examining the cause of the differences, the possibilities that the diffusion of clusters of 
and 
is slower than the model and that vacancy clusters are generated by applying strain and H charging concurrently were indicated.
Ebihara, Kenichi; Sugiyama, Yuri*; Takai, Kenichi*; Matsumoto, Ryosuke*; Suzudo, Tomoaki
no journal, ,
no abstracts in English
Ebihara, Kenichi; Sugiyama, Yuri*; Matsumoto, Ryosuke*; Takai, Kenichi*; Suzudo, Tomoaki
no journal, ,
A hydrogen embrittlement model supposes that vacancies in steel which are generated by hydrogen charging and deformation concurrently cause directly embrittlement. Moreover, a characteristic peak appears in the hydrogen thermal desorption spectrum of such steel. Therefore, it is considered that vacancies and vacancy clusters resulting from vacancy aggregation can be estimated quantitatively by numerically simulating such a spectrum for verifying the model. In this study, the thermal desorption spectra of an iron specimen with strain-induced vacancies was measured, and the spectra was simulated using a model considering the behavior of vacancies and vacancy clusters. The possibility that diffusion of some kinds of vacancy clusters may be slower than the theoretical value was indicated from the result. Furthermore, we discuss the measurement of the thermal desorption curve immediately after the vacancy formation. This presentation includes a part of Metal. Mater. Trans. A52 (2021) 257.
