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Tsuru, Tomohito; Han, S.*; Matsuura, Shutaro*; Chen, Z.*; Kishida, Kyosuke; Lobzenko, I.; Rao, S.*; Woodward, C.*; George, E.*; Inui, Haruyuki*
Nature Communications (Internet), 15, p.1706_1 - 1706_10, 2024/02
Refractory high-entropy alloys (RHEAs) have attracted attention because of their potential for use in ultrahigh-temperature applications. Unfortunately, their body-centered-cubic (BCC) crystal structures make them more brittle than the ductile and fracture-resistant face-centered-cubic (FCC) HEAs. RHEAs also display significantly lower creep strengths than a leading Ni-base superalloy and its FCC matrix. To overcome these drawbacks and develop RHEAs into viable structural materials, improved fundamental understanding is needed of factors that control strength and ductility. Here we investigate two model RHEAs, TiZrHfNbTa and VNbMoTaW, and show that the former is plastically compressible down to 77 K, whereas the latter is not below 298 K. We find that hexagonal close-packed (HCP) elements in TiZrHfNbTa lower its dislocation core energy, increase its lattice distortion, and lower its shear modulus relative to VNbMoTaW whose elements are all BCC, leading to the formers higher ductility and modulus-normalized yield strength. Consistent with our yield strength models, primarily screw dislocations are present in TiZrHfNbTa after deformation, but equal numbers of edge and screw segments in VNbTaMoW. Dislocation cores are compact in VNbTaMoW and extended in TiZrHfNbTa, and different macroscopic slip planes are activated in the two RHEAs, which we attribute to the concentration of HCP elements. Our findings demonstrate how electronic structure changes related to the ratio of HCP to BCC elements can be used to control strength, ductility, and slip behavior to develop the next generation of high-temperature materials for more efficient power plants and transportation.
Tsuru, Tomohito; Lobzenko, I.; Ogata, Shigenobu*; Han, W.-Z.*
Journal of Materials Research and Technology, 28, p.1013 - 1021, 2024/01
Some solute atoms induce hardening and embrittlement in body-centered-cubic refractory metals. Especially interstitial oxygen has a dramatic hardening effect in Nb, where the yield stress of oxygen-doped Nb alloys becomes more than twice as high as that of pure Nb. Conventional mechanisms cannot explain the oxygen-induced dramatic hardening since the interaction between dislocation and oxygen is relatively weak. Here, we focused on the three-body interaction of a screw dislocation with oxygen and vacancy. Our first-principles calculations revealed that the formation of vacancy-oxygen pair enhances the attractive interaction with a screw dislocation though the interaction between oxygen and dislocation is repulsive. Furthermore, this feature was found to be a unique nature of oxygen in Nb. The vacancy-oxygen pair increases the energy barrier for dislocation motion more significantly than an isolated vacancy and oxygen interstitial. We have discovered a new oxygen-induced mechanism: a unique octahedral-tetrahedral shuffling process of oxygen dominantly contributes to the dramatic hardening. Thus, the widely distributed vacancy-oxygen pairs behave as strong obstacles for dislocation motion that causes damage accumulation and successive hardening in oxygen-doped BCC alloys.
Tamii, Atsushi*; Pellegri, L.*; Sderstrm, P.-A.*; Allard, D.*; Goriely, S.*; Inakura, Tsunenori*; Khan, E.*; Kido, Eiji*; Kimura, Masaaki*; Litvinova, E.*; et al.
European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09
no abstracts in English
Visuri, A.-M.*; Mohan, J.*; Uchino, Shun; Huang, M.-Z.*; Esslinger, T.*; Giamarchi, T.*
Physical Review Research (Internet), 5(3), p.033095_1 - 033095_11, 2023/08
We study the current-voltage characteristics of a superconducting junction with particle losses at the contacts. We adopt the Keldysh formalism to compute the steady-state current for varying transmission of the contact. In the low transmission regime, the dissipation leads to an enhancement of the current at low bias, a nonmonotonic dependence of current on dissipation, and the emergence of new structures in the current-voltage curves. The effect of dissipation by particle loss is found to be qualitatively different from that of a finite temperature and a finite inelastic scattering rate in the reservoirs.
Huang, M.-Z.*; Mohan, J.*; Visuri, A.-M.*; Fabritius, P.*; Talebi, M.*; Wili, S.*; Uchino, Shun; Giamarchi, T.*; Esslinger, T.*
Physical Review Letters, 130(20), p.200404_1 - 200404_8, 2023/05
Times Cited Count:1 Percentile:83.24(Physics, Multidisciplinary)We measure superfluid transport of strongly-interacting fermionic lithium atoms through a quantum point contact with local, spin-dependent particle loss. We observe that the characteristic non-Ohmic superfluid transport enabled by high-order multiple Andreev reflections transitions into an excess Ohmic current as the dissipation strength exceeds the superfluid gap. We develop a model with mean-field reservoirs connected via tunneling to a dissipative site. Our calculations in the Keldysh formalism reproduce the observed non-equilibrium particle current, yet do not fully explain the observed loss rate or spin current.
Boznar, M. Z.*; Charnock, T. W.*; Chouhan, S. L.*; Grsic, Z.*; Halsall, C.*; Heinrich, G.*; Helebrant, J.*; Hettrich, S.*; Kua, P.*; Mancini, F.*; et al.
IAEA-TECDOC-2001, 226 Pages, 2022/06
The IAEA organized a programme from 2012 to 2015 entitled Modelling and Data for Radiological Impact Assessments (MODARIA), which aimed to improve capabilities in the field of environmental radiation dose assessment by acquiring improved data, model testing and comparison of model inputs, assumptions and outputs, reaching a consensus on modelling philosophies, aligning approaches and parameter values, developing improved methods and exchanging information. This publication describes the activities of Working Group 2, Exposures in Contaminated Urban Environments and Effect of Remedial Measures.
Thiessen, K. M.*; Boznar, M. Z.*; Charnock, T. W.*; Chouhan, S. L.*; Federspiel, L.; Grai, B.*; Grsic, Z.*; Helebrant, J.*; Hettrich, S.*; Hulka, J.*; et al.
Journal of Radiological Protection, 42(2), p.020502_1 - 020502_8, 2022/06
Times Cited Count:4 Percentile:80.29(Environmental Sciences)Yan, S. Q.*; Li, X. Y.*; Nishio, Katsuhisa; Lugaro, M.*; Li, Z. H.*; Makii, Hiroyuki; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; Hirose, Kentaro; et al.
Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10
Times Cited Count:1 Percentile:9.31(Astronomy & Astrophysics)Soba, A.*; Prudil, A.*; Zhang, J.*; Dethioux, A.*; Han, Z.*; Dostal, M.*; Matocha, V.*; Marelle, V.*; Lasnel-Payan, J.*; Kulacsy, K.*; et al.
Proceedings of TopFuel 2021 (Internet), 10 Pages, 2021/10
Tanaka, Junki*; Yang, Z.*; Typel, S.*; Adachi, Satoshi*; Bai, S.*; van Beek, P.*; Beaumel, D.*; Fujikawa, Yuki*; Han, J.*; Heil, S.*; et al.
Science, 371(6526), p.260 - 264, 2021/01
Times Cited Count:30 Percentile:99.14(Multidisciplinary Sciences)By employing quasi-free -cluster-knockout reactions, we obtained direct experimental evidence for the formation of clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between -cluster formation and the neutron skin.
Dimitriou, P.*; Basunia, S*; Bernstein, L.*; Chen, J.*; Elekes, Z.*; Huang, X.*; Hurst, A.*; Iimura, Hideki; Jain, A. K.*; Kelley, J.*; et al.
EPJ Web of Conferences, 239, p.15004_1 - 15004_4, 2020/09
Times Cited Count:0 Percentile:0.1The Evaluated Nuclear Structure Data File (ENSDF) includes the most extensive and comprehensive set of nuclear structure and decay data evaluations performed by the international network of Nuclear Structure and Decay Data evaluators (NSDD) under the auspices of the IAEA. In this report we describe some of the recent NSDD activities and provide future perspectives.
Yang, P.-J.*; Li, Q.-J.*; Tsuru, Tomohito; Ogata, Shigenobu*; Zhang, J.-W.*; Sheng, H.-W.*; Shan, Z.-W.*; Sha, G.*; Han, W.-Z.*; Li, J.*; et al.
Acta Materialia, 168, p.331 - 342, 2019/04
Times Cited Count:47 Percentile:96.1(Materials Science, Multidisciplinary)Body-centred-cubic metallic materials, such as niobium (Nb) and other refractory metals, are prone to embrittlement due to low levels of oxygen solutes. The mechanisms responsible for the oxygen-induced rampant hardening and damage are unclear. Here we illustrate that screw dislocations moving through a random repulsive force field imposed by impurity oxygen interstitials readily form cross-kinks and emit excess vacancies in Nb. The vacancies bind strongly with oxygen and screw dislocation in a three-body fashion, rendering dislocation motion difficult and hence pronounced dislocation storage and hardening. This leads to unusually high strain hardening rates and fast breeding of nano-cavities that underlie damage and failure.
Tsekhanovich, I.*; Andreyev, A. N.; Nishio, Katsuhisa; Denis-Petit, D.*; Hirose, Kentaro; Makii, Hiroyuki; Matheson, Z.*; Morimoto, Koji*; Morita, Kosuke*; Nazarewicz, W.*; et al.
Physics Letters B, 790, p.583 - 588, 2019/03
Times Cited Count:30 Percentile:94.76(Astronomy & Astrophysics)Tang, C.*; Song, Q.*; Chang, C.-Z.*; Xu, Y.*; Onuma, Yuichi; Matsuo, Mamoru*; Liu, Y.*; Yuan, W.*; Yao, Y.*; Moodera, J. S.*; et al.
Science Advances (Internet), 4(6), p.eaas8660_1 - eaas8660_6, 2018/06
Times Cited Count:27 Percentile:84.7(Multidisciplinary Sciences)Kristo, M. J.*; Williams, R.*; Gaffney, A. M.*; Kayzar-Boggs, T. M.*; Schorzman, K. C.*; Lagerkvist, P.*; Vesterlund, A.*; Ramebck, H.*; Nelwamondo, A. N.*; Kotze, D.*; et al.
Journal of Radioanalytical and Nuclear Chemistry, 315(2), p.425 - 434, 2018/02
Times Cited Count:12 Percentile:82.06(Chemistry, Analytical)In a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on three low enriched uranium oxide samples, providing 12 analytical results using three different parent-daughter pairs serving as independent chronometers. The vast majority of the results were consistent with one another and consistent with the known processing history of the materials. In general, for these particular samples, mass spectrometry gave more accurate and more precise analytical results than decay counting measurements. In addition, the concordance of the U-Pa and U-Th chronometers confirmed the validity of the age dating assumptions, increasing confidence in the resulting conclusions.
Yan, S. Q.*; Li, Z. H.*; Wang, Y. B.*; Nishio, Katsuhisa; Lugaro, M.*; Karakas, A. I.*; Makii, Hiroyuki; Mohr, P.*; Su, J.*; Li, Y. J.*; et al.
Astrophysical Journal, 848(2), p.98_1 - 98_8, 2017/10
Times Cited Count:5 Percentile:21.72(Astronomy & Astrophysics)Yan, S. Q.*; Li, Z. H.*; Wang, Y. B.*; Nishio, Katsuhisa; Makii, Hiroyuki; Su, J.*; Li, Y. J.*; Nishinaka, Ichiro; Hirose, Kentaro; Han, Y. L.*; et al.
Physical Review C, 94(1), p.015804_1 - 015804_5, 2016/07
Times Cited Count:6 Percentile:44.68(Physics, Nuclear)Naushad, M.*; Khan, M. R.*; Alothman, Z. A.*; Awual, M. R.
Desalination and water treatment, 57(13), p.5781 - 5788, 2016/03
Times Cited Count:54 Percentile:93.29(Engineering, Chemical)Kiriyama, Hiromitsu; Mori, Michiaki; Pirozhkov, A. S.; Ogura, Koichi; Sagisaka, Akito; Kon, Akira; Esirkepov, T. Z.; Hayashi, Yukio; Kotaki, Hideyuki; Kanasaki, Masato*; et al.
IEEE Journal of Selected Topics in Quantum Electronics, 21(1), p.1601118_1 - 1601118_18, 2015/01
Times Cited Count:60 Percentile:95.4(Engineering, Electrical & Electronic)This paper reviews the development of a high-contrast high-intensity petawatt-class Ti:sapphire chirped-pulse amplification (CPA) laser for research on high field science. We discuss in detail the design, performance and characterization of the laser. We also describe the on-going upgrade of the laser system and some applications for the laser in relativistic dominated laser-matter interactions.
Sanetullaev, A.*; Tsang, M. B.*; Lynch, W. G.*; Lee, J.*; Bazin, D.*; Chan, K. P.*; Coupland, D.*; Hanzl, V.*; Hanzlova, D.*; Kilburn, M.*; et al.
Physics Letters B, 736, p.137 - 141, 2014/09
Times Cited Count:12 Percentile:67.92(Astronomy & Astrophysics)no abstracts in English