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Journal Articles

Temperature-dependent hardening contributions in CrFeCoNi high-entropy alloy

Naeem, M.*; He, H.*; Harjo, S.; Kawasaki, Takuro; Lin, W.*; Kai, J.-J.*; Wu, Z.*; Lan, S.*; Wang, X.-L.*

Acta Materialia, 221, p.117371_1 - 117371_18, 2021/12

Journal Articles

Multiple deformation scheme in direct energy deposited CoCrNi medium entropy alloy at 210K

Kim, Y. S.*; Chae, H.*; Woo, W.*; Kim, D.-K.*; Lee, D.-H.*; Harjo, S.; Kawasaki, Takuro; Lee, S. Y.*

Materials Science & Engineering A, 828, p.142059_1 - 142059_10, 2021/11

Journal Articles

Martensitic transformation in CrCoNi medium-entropy alloy at cryogenic temperature

Naeem, M.*; Zhou, H.*; He, H.*; Harjo, S.; Kawasaki, Takuro; Lan, S.*; Wu, Z.*; Zhu, Y.*; Wang, X.-L.*

Applied Physics Letters, 119(13), p.131901_1 - 131901_7, 2021/09

Journal Articles

Mechanism of strengthening in cast iron by pulsed neutron beam

Harjo, S.

Kensa Gijutsu, 26(9), p.9 - 13, 2021/09

no abstracts in English

Journal Articles

Phase transition and chemical reactivity of 1H-tetrazole under high pressure up to 100 GPa

Gao, D.*; Tang, X.*; Wang, X.*; Yang, X.*; Zhang, P.*; Che, G.*; Han, J.*; Hattori, Takanori; Wang, Y.*; Dong, X.*; et al.

Physical Chemistry Chemical Physics, 23(35), p.19503 - 19510, 2021/09

 Times Cited Count:0

Pressure-induced phase transition and polymerization of nitrogen-rich molecules are widely focused due to its extreme importance for the development of green high energy density materials. Here, we present a study of the phase transition and chemical reaction of 1H-tetrazole up to 100 GPa by using ${it in situ}$ Raman, IR, X-ray diffraction, neutron diffraction techniques and theoretical calculation. A phase transition above 2.6 GPa was identified and the high-pressure structure was determined with one molecule in a unit cell. The 1H-tetrazole polymerizes reversibly below 100 GPa, probably through a carbon-nitrogen bonding instead of nitrogen-nitrogen bonding. Our studies updated the structure model of the high pressure phase of 1H-tetrazole, and presented the possible intermolecular bonding route for the first time, which gives new insights to understand the phase transition and chemical reaction of nitrogen-rich compounds, and benefit for designing new high energy density materials.

Journal Articles

Behavior of light elements in iron-silicate-water-sulfur system during early Earth's evolution

Iizuka, Riko*; Goto, Hirotada*; Shito, Chikara*; Fukuyama, Ko*; Mori, Yuichiro*; Hattori, Takanori; Sano, Asami; Funakoshi, Kenichi*; Kagi, Hiroyuki*

Scientific Reports (Internet), 11(1), p.12632_1 - 12632_10, 2021/06

 Times Cited Count:0 Percentile:0.01(Multidisciplinary Sciences)

The Earth's core consist of Fe-Ni alloy with some light elements (H, C, O, Si, S etc.). Hydrogen (H) is the most abundant element in the universe and one of the promising candidates. In this study, we have investigated the effects of sulfur(S) on hydrogenation of iron-hydrous silicate system containing saturated water in the ideal composition of the primitive Earth. We observed a series of phase transitions of Fe, dehydration of the hydrous mineral, and formation of olivine and enstatite with increasing temperature. The FeS formed as the coexisting phase of Fe under high-pressure and temperature condition, but its unit cell volume did not increase, suggesting that FeS is hardly hydrogenated. Recovered samples exhibited that H and S can be incorporated into solid Fe, which lowers the melting temperature as Fe(H$$_{x}$$)-FeS system. No detection of other light elements (C, O, Si) in solid Fe suggests that they dissolve into molten iron hydride and/or FeS in the later process of Earth's core-mantle differentiation.

Journal Articles

Correlated Li-ion migration in the superionic conductor Li$$_{10}$$GeP$$_{2}$$S$$_{12}$$

Yajima, Takeshi*; Hinuma, Yoyo*; Hori, Satoshi*; Iwasaki, Rui*; Kanno, Ryoji*; Ohara, Takashi; Nakao, Akiko*; Munakata, Koji*; Hiroi, Zenji*

Journal of Materials Chemistry A, 9(18), p.11278 - 11284, 2021/05

 Times Cited Count:0 Percentile:0(Chemistry, Physical)

Journal Articles

Development of microstructural analysis and evaluation techniques of steel materials using RIKEN compact accelerator-driven neutron source (RANS)

Xu, P. G.; Takamura, Masato*; Iwamoto, Chihiro*; Hakoyama, Tomoyuki*; Otake, Yoshie*; Suzuki, Hiroshi

Isotope News, (774), p.7 - 10, 2021/04

no abstracts in English

Journal Articles

Crystal structure of nesquehonite, MgCO$$_{3}$$ $$cdot$$ 3H(D)$$_{2}$$O by neutron diffraction and effect of pH on structural formulas of nesquehonite

Yamamoto, Genichiro*; Kyono, Atsushi*; Abe, Jun*; Sano, Asami; Hattori, Takanori

Journal of Mineralogical and Petrological Sciences, 116(2), p.96 - 103, 2021/04

 Times Cited Count:0 Percentile:0.04(Mineralogy)

Neutron diffraction, Raman spectroscopy, and thermal analysis were performed to investigate the composition, structure, and formation conditions of the magnesium carbonate hydrate nesquehonite. The time-of-flight neutron diffraction revealed the crystal structure of the monoclinic space group $$P$$2$$_{1}/n$$ with lattice parameters of $$a$$=7.72100(12)$AA, $b$$=5.37518(7)$AA, $c$$=12.1430(3)$AA, $beta$$=90.165(4)$$^circ$$, in which two deuterium atoms are coordinated to the O1, O2, and O6 atoms to form water molecules. The three water molecules in the structure suggests the structural formula of the nesquehonite should be MgCO$$_{3}$$ $$cdot$$ 3H$$_{2}$$O rather than Mg(HCO$$_{3}$$)(OH) $$cdot $$2H$$_{2}$$O.

Journal Articles

Observation of dihydrogen bonds in high-pressure phases of ammonia borane by X-ray and neutron diffraction measurements

Nakano, Satoshi*; Sano, Asami; Hattori, Takanori; Machida, Shinichi*; Komatsu, Kazuki*; Fujihisa, Hiroshi*; Yamawaki, Hiroshi*; Goto, Yoshito*; Kikegawa, Takumi*

Inorganic Chemistry, 60(5), p.3065 - 3073, 2021/03

 Times Cited Count:0 Percentile:0.01(Chemistry, Inorganic & Nuclear)

X-ray and neutron diffraction analyses of ammonia borane were conducted at ambient and high pressures. The H-H distance in dihydrogen bonds was shorter than twice the van der Waals radius (2.4 ${AA}$). The half of the dihydrogen bonds were broken on phase transition from AP to the first high pressure phase (HP1) at approximately 1.2 GPa as revealed by an increase in the H-H distances. On further pressure increase, all of the H-H distances became shorter than 2.4 ${AA}$ again, implying the pressure-induced reformation of the dihydrogen bonds. Furthermore, the HP1 transformed to the second one with the structure of $$P2_1$$ (Z = 2) at about 11 GPa. In this phase transition, the inclination of the molecule axis became larger and the number of types of dihydrogen bonds increased from 6 to 11. Just before the third transition at 18.9 GPa, the shortest dihydrogen bond decreased to 1.65 ${AA}$. The present study experimentally first confirmed the breakage and reformation of the dihydrogen bonds by the structural change under pressure.

Journal Articles

Local- and intermediate-range order in room temperature superionic conducting Ag-GeSe$$_{3}$$ glasses

Hosokawa, Shinya*; Kawakita, Yukinobu; Stellhorn, J. R.*; Pusztai, L.*; Blanc, N.*; Boudet, N.*; Ikeda, Kazutaka*; Otomo, Toshiya*

JPS Conference Proceedings (Internet), 33, p.011070_1 - 011070_7, 2021/03

Local- and intermediate-range atomic order in Ag ion conducting glasses Ag$$_{x}$$(GeSe$$_{3}$$)$$_{1-x}$$ with x = 0.15, 0.28, 0.33, and 0.50 were investigated by using a combination of AXS, XRD, ND, and RMC modeling. By adding the ND pdf to AXS and XRD results, reasonable partial structure factors and partial pdf were obtained by the RMC procedure. In contrast to the previous AXS and RMC study, a large number of Ag-Ge and Ge-Ge correlations are observed in the first coordination shell region, which is consistent with an ${it ab initio}$ MD simulation. The coordination numbers around the Ge and Se mostly follow the 8-$$N$$ rule over all Ag concentrations if Ag is not taken into account. With increasing the Ag concentration, the partial coordination numbers with Ge and Se atoms around Ag remarkably increases, while the Ag-Ag coordination number increases only slightly, indicating that the Ag conducting path is formed through the second neighboring Ag-Ag correlations.

Journal Articles

Suppressed lattice disorder for large emission enhancement and structural robustness in hybrid lead iodide perovskite discovered by high-pressure isotope effect

Kong, L.*; Gong, J.*; Hu, Q.*; Capitani, F.*; Celeste, A.*; Hattori, Takanori; Sano, Asami; Li, N.*; Yang, W.*; Liu, G.*; et al.

Advanced Functional Materials, 31(9), p.2009131_1 - 2009131_12, 2021/02

 Times Cited Count:1 Percentile:27.27(Chemistry, Multidisciplinary)

The soft nature of organic-inorganic halide perovskites renders their lattice particularly tunable to external stimuli such as pressure, undoubtedly offering an effective way to modify their structure for extraordinary optoelectronic properties. However, these soft materials meanwhile feature a general characteristic that even a very mild pressure will lead to detrimental lattice distortion and weaken the critical light-matter interaction, thereby triggering the performance degradation. Here, using the methylammonium lead iodide as a representative exploratory platform, we observed the pressure-driven lattice disorder can be significantly suppressed via hydrogen isotope effect, which is crucial for better optical and mechanical properties previously unattainable.

Journal Articles

Effect of the difference in strength of hard and soft components on the synergetic strengthening of layered materials

Kim, J. G.*; Bae, J. W.*; Park, J. M.*; Woo, W.*; Harjo, S.; Lee, S.*; Kim, H. S.*

Metals and Materials International, 27(2), p.376 - 383, 2021/02

 Times Cited Count:2 Percentile:48.93(Materials Science, Multidisciplinary)

Journal Articles

Stacking fault driven phase transformation in CrCoNi medium entropy alloy

He, H.*; Naeem, M.*; Zhang, F.*; Zhao, Y.*; Harjo, S.; Kawasaki, Takuro; Wang, B.*; Wu, X.*; Lan, S.*; Wu, Z.*; et al.

Nano Letters, 21(3), p.1419 - 1426, 2021/02

 Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)

Journal Articles

Innovative measurement technique and evaluation method for unfilled portion in adhesive post-installed anchor

Ito, Michitane*; Mukai, Tomohisa*; Suzuki, Hiroshi; Nanbu, Yoshihito*; Suzuki, Junichi*; Matsuzawa, Koichi*; Kinugasa, Hideyuki*

Nihon Kenchiku Gakkai Gijutsu Hokokushu, 27(65), p.99 - 103, 2021/02

no abstracts in English

Journal Articles

Quantifying internal strains, stresses, and dislocation density in additively manufactured AlSi10Mg during loading-unloading-reloading deformation

Zhang, X. X.*; Andr$"a$, H.*; Harjo, S.; Gong, W.*; Kawasaki, Takuro; Lutz, A.*; Lahres, M.*

Materials & Design, 198, p.109339_1 - 109339_9, 2021/01

 Times Cited Count:6 Percentile:94.35(Materials Science, Multidisciplinary)

Journal Articles

Enhancement of fatigue resistance by overload-induced deformation twinning in a CoCrFeMnNi high-entropy alloy

Lam, T.-N.*; Lee, S. Y.*; Tsou, N.-T.*; Chou, H.-S.*; Lai, B.-H.*; Chang, Y.-J.*; Feng, R.*; Kawasaki, Takuro; Harjo, S.; Liaw, P. K.*; et al.

Acta Materialia, 201, p.412 - 424, 2020/12

 Times Cited Count:10 Percentile:84.02(Materials Science, Multidisciplinary)

Journal Articles

Element effects of Mn and Ge on the tuning of mechanical properties of high-entropy alloys

Lam, T.-N.*; Tsai, C.-W.*; Chen, B.-K.*; Lai, B.-H.*; Liu, H.-C*; Kawasaki, Takuro; Harjo, S.; Lin, B.-H.*; Huang, E.-W.*

Metallurgical and Materials Transactions A, 51(10), p.5023 - 5028, 2020/10

 Times Cited Count:3 Percentile:48.93(Materials Science, Multidisciplinary)

Journal Articles

Neutron diffraction monitoring of ductile cast iron under cyclic tension-compression

Harjo, S.; Kubota, Satoru*; Gong, W.*; Kawasaki, Takuro; Gao, S.*

Acta Materialia, 196, p.584 - 594, 2020/09

 Times Cited Count:3 Percentile:62.78(Materials Science, Multidisciplinary)

Journal Articles

Practical effects of pressure-transmitting media on neutron diffraction experiments using Paris-Edinburgh presses

Hattori, Takanori; Sano, Asami; Machida, Shinichi*; Ouchi, Keiichi*; Kira, Hiroshi*; Abe, Jun*; Funakoshi, Kenichi*

High Pressure Research, 40(3), p.325 - 338, 2020/09

 Times Cited Count:1 Percentile:34.55(Physics, Multidisciplinary)

To understand the practical effects of pressure-transmitting media (PTM) on neutron diffraction using Paris-Edinburgh presses, diffraction patterns of MgO were collected to approximately 20 GPa using PTMs of Pb, AgCl, 4:1 methano-ethanol (ME) mixture with and without heating, N$$_2$$, and Ar. Hydrostaticity in the sample chamber estimated from the MgO 220 peak width improves in the order of Pb, AgCl, Ar, ME mixture, N$$_2$$, and the heated ME mixture. Unlike previous results using a diamond anvil cell, the unheated ME mixture is superior to Ar even after freezing, probably due to the cup on the anvil face. Considering these results and the sizable coherent scattering of Ne, which would show good hydrostaticity, we conclude that the ME mixture (preferably the heated one) is the best PTM in neutron experiments up to 20 GPa, while Ar can be substituted when a sample is reactive to alcohols.

386 (Records 1-20 displayed on this page)