Article
Nanoscience & Nanotechnology
Anette B. Hagen, Sigurd Wenner, Ruben Bjorge, Di Wan, Calin D. Marioara, Randi Holmestad, Inga G. Ringdalen
Summary: Al-Mg-Si (6xxx series) alloys exhibit strong mechanical properties but are weakened by a soft precipitation free zone (PFZ) near grain boundaries during heat treatment, reducing material ductility. This study employs nanoindentation and microstructure characterization to quantitatively analyze these alloys. Experimental results confirm that the PFZ weakens the material, while an adjacent region exhibits increased hardness due to a higher density of precipitates. This previously unrecognized harder zone has important implications for the mechanical properties of large-grained aluminum alloys.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Physics, Condensed Matter
Edward Tindibale, Winfred M. Mulwa, Bamidele I. Adetunji
Summary: Ab-initio calculations were performed using density functional theory (DFT) implemented in the Quantum ESPRESSO (QE) code. Minimal lattice parameter mismatch was observed in TiNiSn/TiNi2Sn, ZrNiSn/ZrNi2Sn, and HfNiSn/HfNi2Sn compounds (2.5% - 3%). Half-Heusler compounds exhibited shorter bond lengths and smaller bulk moduli compared to full-Heusler counterparts. The elastic constants were used to study the directional dependence of the Young's and shear moduli. TiNiGe, HfNiSn, and ZrNiSn had higher universal anisotropy index among the half-Heusler compounds.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Nanoscience & Nanotechnology
M. Zhang, R. J. Lewis, J. C. Gibeling
Summary: Creep experiments on a rapidly solidified Al-8.5 wt% Fe-1.3 wt% V-1.7 wt% Si alloy suggest that it exhibits similar or superior deformation resistance compared to other high temperature Al alloys. Stress reduction results show that FVS0812 exhibits similar creep characteristics to those of other dispersion-strengthened alloys under constant structure conditions following stress reductions, even though the creep mechanism is determined to be significantly different. The role of the particles is to carry a portion of the applied load rather than causing dislocation detachment, local climb, or general climb.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Multidisciplinary Sciences
Haijun Huang, Lili Fan, Xun Liu, Feng Xu, Ye Wu, Gang Yang, Chunwei Leng, Qingsong Wang, Jidong Weng, Xiang Wang, Lingcang Cai, Yingwei Fei
Summary: Direct measurements of Fe and Fe-8.6 wt%Si under high pressure and high temperature conditions provide insights into the sound velocity and Poisson's ratio of core materials. Adding carbon may be a possible solution to explain the observed anomalies.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Abu Bakar, A. Afaq, Muhammad Shoaib, A. Dahshan, Muhammad Asif
Summary: This paper presents a comparative study of the elastic, mechanical, electronic, and optical response of RuCrX (X=Si, Ge, Sn). The materials are found to be flexible and ductile, with high hardness and stiffness, making them suitable for high-temperature environments. They exhibit non-magnetic metallic properties and can be used in opto-electronic devices and sensors.
Article
Chemistry, Inorganic & Nuclear
Salem Hebri, Abdel-Basset Abdelli, Nassir Belfedal, Djillali Bensaid
Summary: In this study, a new class of stable semiconducting equiatomic quaternary Heusler alloys is introduced. 21 new semiconductors with 18 valence electrons per unit cell are reported. Three different structural arrangements, referred to as Y1, Y2, and Y3, are considered. The bandgaps are initially underestimated by the GGA-PBE functional, but corrected values are obtained using the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional. The energy gaps of these quaternary Heusler semiconductors range from 0.766-1.94 eV, suggesting their potential for various applications such as thermoelectric, optoelectronic, and photovoltaic. Formation energy, elastic constants, and phonon dispersion curves are also calculated to verify the mechanical and dynamical stabilities of these alloys.
INORGANIC CHEMISTRY COMMUNICATIONS
(2023)
Article
Engineering, Manufacturing
I Ferretto, D. Kim, N. M. Della Ventura, M. Shahverdi, W. Lee, C. Leinenbach
Summary: The iron-based Fe-17Mn-5Si-10Cr-4Ni shape memory alloy (SMA) manufactured by laser powder bed fusion (LPBF) exhibits high strength, elongation, and ductility after annealing, as well as pronounced shape memory effect (SME) and pseudo-elasticity (PE) exceeding those of conventionally fabricated alloys. The texture generated during the LPBF process significantly influences SME and PE, with improved strain recovery observed when the loading direction is parallel to the build direction.
ADDITIVE MANUFACTURING
(2021)
Article
Nanoscience & Nanotechnology
Qing Cai, Changming Fang, Ewan Lordan, Yun Wang, Isaac T. H. Chang, Brian Cantor
Summary: A novel near-eutectic Al-15.0Si-4.1Ni-1.9Fe (wt%) alloy with a ternary eutectic reaction was investigated. The alloy exhibited short nanoscale fibrous morphologies of eutectic Si and (Al,Si)5(Fe,Ni) phases. The newly developed alloy displayed superior mechanical properties at room and elevated temperatures compared with other heat-resistant aluminium alloys, suggesting great potential for industrial applications.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Qin Zou, Xihui Ye, Yanguo Li, Wenqi Luo, Xiaowei Yang, Yongan Luo
Summary: The effects of Ti on the microstructure and properties of the Fe-20Mn-6Si-8Cr-5Ni shape memory alloy prepared by powder metallurgy were investigated. The results showed that trace Ti elements could improve the alloy's mechanical properties and shape memory performance, but an excess of Ti had adverse effects. The Ti content also played a role in the corrosion resistance of the alloy.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Abdollah Bahador, Junko Umeda, Ridvan Yamanoglu, Tuty Asma Abu Bakar, Katsuyoshi Kondoh
Summary: Fully dense powder metallurgy (PM) Ti-4Fe-0.2O-3Cu-0.4Si alloy was produced using spark plasma sintering (SPS) and hot extrusion to develop an inexpensive high strength dual-phase Ti alloy. The addition of Si solute remarkably enhanced the microstructure stability and yield strength of the alloy at high temperature. The principal strengthening mechanisms were grain refinement and solid solution phenomena, leading to a comparatively higher tensile strength of the alloy compared to conventional Ti-6Al-4V alloy produced by a similar method.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
DaeHan Kim, JaeHwang Kim, Jae-Yeol Jeon, Young-Won Kim, Equo Kobayashi
Summary: The local elongation behavior of Al-4.5Si-1.0Cu-0.3Mg(-1.0Fe) alloys produced by a deformation-semisolid extrusion process was investigated, with uniform and large local elongation confirmed in the 1 Fe alloy. The correlation between fragmented Fe-IMCs and local elongation was discussed, with high densities of fragmented Fe-IMCs and grain boundaries providing numerous locations for dislocation accumulation. The dislocation density of the as-extruded 1 Fe alloy was estimated with different strain levels, with more locations of dislocation multiplication extending the local elongation behavior of the alloy.
Article
Materials Science, Multidisciplinary
Fabio Martins Cardoso, Cristina Bormio-Nunes
Summary: The study successfully prepared a FeCoNi(GaNb)(0.20) multicomponent alloy with low magnetostriction and high permeability values, suitable for use in electric machines and magnetic devices in the subkilohertz frequency range.
ADVANCED ENGINEERING MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
A. V. Mikhaylovskaya, M. Esmaeili Ghayoumabadi, A. G. Mochugovskiy
Summary: The study investigated the influence of different alloying elements on the microstructural evolution, superplastic behavior, and tensile properties of Al-Mg-Si-based alloys, with a focus on the formation of dispersoids and particle size distribution after thermomechanical treatment. The alloys studied exhibited good superplastic behavior within specific temperature and strain rate limits, along with improved mechanical properties after age-hardening heat treatment.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Yuhit Gupta, M. M. Sinha, S. S. Verma
Summary: The emergent passion for half-Heusler alloys is driven by their drastic thermoelectric properties for spintronics applications. A detailed study of the elastic, mechanical, and thermodynamical properties of the novel half-Heusler alloy 'AlNiP' using Density Functional Theory (DFT) and semi-classical Boltzmann transport theory has been conducted, providing insight into its stability, metallic bonding, and performance under different temperatures. The computational appraisal includes evaluations of elastic properties, thermodynamic calculations, and estimates of key parameters like Seebeck coefficient, lattice thermal conductivity, and figure of merit, paving the way for potential experimental research and applications.
MATERIALS CHEMISTRY AND PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Chenglong Qin, Yushu Yu, Zihan Xu, Jiguang Du, Liang Zhao, Gang Jiang
Summary: The mechanical, thermodynamic, and surface properties of U-Si alloys were investigated using density functional theory calculations. The results showed that U3Si2 exhibited brittleness, while the remaining U-Si alloys demonstrated reliable ductility. The study also calculated the sound velocity, Debye temperature, and surface properties of the alloys.
Article
Physics, Applied
Yutaka Ohno, Jie Ren, Shingo Tanaka, Masanori Kohyama, Koji Inoue, Yasuo Shimizu, Yasuyoshi Nagai, Hideto Yoshida
Summary: Through the use of atom probe tomography combined with a focused ion beam operated at -150 degrees C, the three-dimensional distribution of oxygen atoms segregated at sigma 9{114} grain boundaries in Czochralski-grown silicon ingots was analyzed with high spatial resolution. The analysis revealed a narrow segregation range of oxygen atoms across the grain boundary plane, with segregation sites existing at bond-centered sites under tensile stresses above 2 GPa, as calculated by ab initio local stress calculations.
APPLIED PHYSICS EXPRESS
(2021)
Article
Chemistry, Physical
Kohei Tada, Shusuke Yamanaka, Takashi Kawakami, Yasutaka Kitagawa, Mitsutaka Okumura, Kizashi Yamaguchi, Shingo Tanaka
Summary: The study established an estimation scheme for spin contamination errors (SCEs) in DFT/plane-wave calculations, and applied it to models with stable antiferromagnetic states to demonstrate the importance of SCE correction in solid systems.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Kohei Tada, Masahiro Mori, Shingo Tanaka
Summary: The study investigated the spin contamination errors in the stability of next-generation Li-ion battery cathode materials using the DFT/plane-wave method, and found that even after correcting for the errors, the relative stability of the Li0.5FeF3 phase remained unchanged.
Article
Chemistry, Multidisciplinary
Kohei Tada, Yasutaka Kitagawa, Takashi Kawakami, Mitsutaka Okumura, Shingo Tanaka
Summary: In this study, an electron density-based estimation scheme for the diradical character was established, showing consistency and qualitative agreement in analyzing open shell structures. The values obtained using different basis sets were shown to be equal, indicating the efficacy of the proposed scheme.
Article
Materials Science, Multidisciplinary
Kohei Tada, Mitsunori Kitta, Shingo Tanaka
Summary: Li4Ti5O12 is an anode material for Li-ion batteries, and Na3LiTi5O12 is a candidate anode material for Na-ion batteries. The difference between these two materials is detected through electron energy loss spectra (EELS). Density functional theory calculations show that the interaction between the cations in the 8a sites and the Ti-O spinel framework affects the properties of the titanates.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Kohei Tada, Mitsunori Kitta, Shingo Tanaka
Summary: This study investigated the impact of alkali metal cation occupancy on the formation of O vacancies in spinel-type titanium oxide. The results suggested that substituting the cation at the 8a-site could enhance catalytic oxidation activity.
Article
Materials Science, Multidisciplinary
Yoyo Hinuma, Masanori Kohyama, Shingo Tanaka
Summary: This study proposes algorithms for constructing tilt grain boundary models without relying on the coincidence site lattice (CSL). By computationally searching, candidate grain boundary planes for a selected rotation axis are obtained, allowing for systematic treatment of diverse grain boundary systems. Surface-slab supercells with shared two-dimensional lattice are used for feasible computational analysis, and a procedure to obtain a GB-model supercell with alternately stacking these slabs is given. The proposed algorithms enable streamlined generation of both symmetric and asymmetric GB models.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Chemistry, Physical
Koji Fujimaru, Kohei Tada, Hiroyuki Ozaki, Mitsutaka Okumura, Shingo Tanaka
Summary: This study investigates the influence of surface interactions on spin contamination errors and diradical character using numerical calculations. The results reveal extreme values and inflections in spin contamination errors, while the diradical character shows monotonic variations. The research also demonstrates that surface interactions affect the diradical character, even when dispersion forces are the main adsorption stabilization factor.
SURFACES AND INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Wenxiong Zhang, Eiji Hosono, Daisuke Asakura, Shingo Tanaka, Masaki Kobayashi, Naoka Nagamura, Masaharu Oshima, Jun Miyawaki, Hisao Kiuchi, Yoshihisa Harada
Summary: This study used microscopic resonant photoelectron spectroscopy to reveal the electronic structure differences of different crystal facets in LiCoO2 cathode particles, finding that the (012) facet is more reactive compared to other facets.
Article
Chemistry, Multidisciplinary
Kohei Tada, Yoyo Hinuma, Satoshi Ichikawa, Shingo Tanaka
Summary: Au/TiO2 systems are widely studied as models for functional nano-interfaces. The crystal shape affects the activity and durability of Au/TiO2 catalysts. Although rutile and anatase TiO2 have been investigated with respect to Au/TiO2 interfaces, there is little knowledge about the Au/brookite TiO2 interaction. In this study, a new Au/brookite TiO2 interface was observed, and density functional theory calculations revealed the strong adsorption of Au atoms on brookite TiO2 (101).
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN
(2023)
Article
Chemistry, Physical
Chiranjita Goswami, Biraj Jyoti Borah, Ruprekha Das, Kohei Tada, Shingo Tanaka, Igor P. Prosvirin, Ilyas Z. Ismagilov, Ekaterina Matus, Mikhail Kerzhentsev, Pankaj Bharali
Summary: Engineering metal/oxide interface and controlling composition are important strategies for efficient Pd-based electrocatalysts. In this study, Pd3M alloy nano-particles anchored on C-CeO2 (Pd3M/C-CeO2, M = Cu, Ni, Co) demonstrated significant performance in formic acid oxidation. The improved activity can be attributed to the electronic and synergistic effects between Pd and the alloyed metal, resulting in lattice contraction and downshift of d-band center. The presence of oxygen vacancies in CeO2 and strong Pd/CeO2 interactions also contribute to the overall electrocatalytic behavior.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
M. Ohno, Y. Chen, Y. Chinda, T. Mohri
Summary: The combination of electronic-structure calculations, the cluster-variation method, and the phase-field method was used to calculate the phase equilibria and microstructural evolution of the disorder-L10 transition in the Fe-Pt system. The calculated transition temperature was close to the experimental value, and the spinodal ordering temperature was determined. The microstructure showed preferential growth of ordered domains along the <100> direction and the development of an anisotropic morphology of an antiphase domain structure. The calculations provided an atomistic interpretation of this morphology, offering consistent first-principles multiscale calculations without any adjusting parameters.
Article
Metallurgy & Metallurgical Engineering
Masanori Kohyama, Shingo Tanaka, Yoshinori Shiihara
Summary: Revealing atomic-scale distributions of energy and stress in defective or complex systems, based on the behavior of electrons, should contribute much to materials science and engineering. Computational techniques of local-energy and local-stress calculations have been developed, which provide novel aspects of phenomena, deep insights into the mechanism, and effective data for novel machine-learning based modelling. Future applications, especially for large-scale metallic systems, are also discussed.
JOURNAL OF THE JAPAN INSTITUTE OF METALS AND MATERIALS
(2023)
Article
Chemistry, Physical
Kohei Tada, Mitsunori Kitta, Shingo Tanaka
Summary: Spinel-type titanate is an important material used as a stable anode for Li-ion batteries and shows superconducting properties upon Li+ doping; new spinel-type titanium oxides with Na+ or Ag+ occupying 8a sites have been discovered. Theoretical calculations based on density functional theory reveal the effects of 8a-site monocations on electronic structures and geometric stabilities, aiding in categorizing the performance of spinel-type titanates. By appropriately selecting cations, spinel titanates can be applied to various materials including battery materials, catalysts, and optical materials.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)