Showing papers by "Naoyuki Hashimoto published in 2020"
TL;DR: In this article, two high entropy alloys, Al0.3CoCrFeNi and CoCrFeMnNi, and a conventional Type 316H stainless steel (SS) were irradiated with 1-MeV krypton ions at 500°C up to 1 dpa, and examined in-situ with a transmission electron microscope.
19 citations
TL;DR: The experiment as well as computer simulation indicate that the composition-dependent particle size of Pt/Au can be explained by the atomic concentration, formation energy of cluster, and the interaction between different metal atoms and PEG molecule.
Abstract: Pt/Au alloy nanoparticles (NPs) in a wide composition range have been synthesized by room-temperature simultaneous sputter deposition from two independent magnetron sources onto liquid PEG (MW = 600). The prepared NPs were alloyed with the face-centered cubic (fcc) structure. In addition, the particle sizes, composition, and shape are strongly correlated but can be tailored by an appropriate variation of the sputtering parameters. No individual particle but large agglomerates with partial alloy structure formed at Pt content of less than 16 atom %. Highly dispersed NPs with no agglomeration were observed in PEG when the quantity of Pt is more than 26 atom %. On the other hand, a small amount of Pt could terminate the agglomeration of Au when sputtering on the grids for transmission electron microscope observation. Our experiment and computer simulation carried out by two different methods indicate that the composition-dependent particle size of Pt/Au can be explained by the atomic concentration, formation energy of the cluster, and interaction between different metal atoms and the PEG molecule.
16 citations
TL;DR: In this article, the number density of stationary self-interstitial atom (SIA) clusters in electron-irradiated α-iron at room temper was measured using highvoltage electron microscopy (HVEM).
Abstract: An in- situ observation using high-voltage electron microscopy (HVEM) showed that the number density of stationary self-interstitial atom (SIA) clusters in electron-irradiated α-iron at room temper...
7 citations
4 citations
TL;DR: In this paper, the dissolution behavior of hydrogen at the Fe/W interface and the effect of H on the strength of the Fe-W interface were investigated by means of first-principle calculation.
Abstract: The dissolution behavior of hydrogen (H) at Fe/W interface and the effect of H on the strength of Fe/W interface are investigated by means of first-principle calculation. The dissolution of H atom ...
4 citations
22 Jul 2020
3 citations
TL;DR: In this paper, the authors investigated the cavity distribution around grain boundary in F82H irradiated by Kr2+ ions with and without helium up to 1 displacement per atom at 500°C and found that the cavity number density and the cavity size tended to decrease and increase as a function of the distance from grain boundary, respectively.
Abstract: F82H were irradiated by Kr2+ ions with and without helium up to 1 displacement per atom at 500 °C, and cavity distribution around grain boundary was investigated by transmission electron microscopy. In F82H irradiated by Kr2+ ions, the cavity number density and the cavity size tended to be decreased and increased as a function of the distance from grain boundary, respectively. This gradient of cavity distribution seemed to be depending on the character of grain boundary. While, the size distribution of cavity seemed to be homogeneous in F82H irradiated by Kr2++He+ ions. This indicates that even prior austenite grain boundary hardly acts as sinks for vacancies if a high number density of helium atoms exists, which is probably due to the decrease in vacancy mobility by helium trapping.
1 citations