A5027757547- Nuclear Materials and Properties
- Fusion materials and technologies
- Microstructure and mechanical properties
- Hydrogen embrittlement and corrosion behaviors in metals
- Magnesium Alloys: Properties and Applications
- Corrosion Behavior and Inhibition
- Theoretical and Computational Physics
- Aluminum Alloy Microstructure Properties
- Aluminum Alloys Composites Properties
- Metal and Thin Film Mechanics
- Ion-surface interactions and analysis
- Machine Learning in Materials Science
- Physics of Superconductivity and Magnetism
- Nuclear and radioactivity studies
- Radioactive contamination and transfer
- Nuclear reactor physics and engineering
- Material Properties and Failure Mechanisms
- nanoparticles nucleation surface interactions
- Advanced Condensed Matter Physics
- Graphite, nuclear technology, radiation studies
- Ultrasonics and Acoustic Wave Propagation
- Advanced Chemical Physics Studies
- Microstructure and Mechanical Properties of Steels
- Magnetic properties of thin films
- Radioactive element chemistry and processing
Japan Atomic Energy Agency
2014-2023
University of Toyama
2017
Kyushu University
2017
The University of Tokyo
1996-1997
We present two interatomic potentials for hydrogen in $\ensuremath{\alpha}$--iron based on the embedded atom method iron developed by Mendelev et al. [Philos. Mag. 83, 3977 (2003)] and Ackland [J. Phys.: Condens. Matter 16, S2629 (2004)]. Since these latter are unique among existing their ability to produce same core structure screw dislocations as density functional theory (DFT) calculations, our also inherit this important feature. use an extensive database of energies atomic...
Atomistic mechanisms of hydrogen-induced cracking along a bcc Fe Σ3(111) symmetrical tilt grain boundary (GB) have been studied by first-principles calculations. The mobile and immobile effects hydrogen on the GB decohesion are analyzed calculating dependence segregation energy coverage relevant to repulsive interaction among segregated atoms at its fracture surfaces, together with generalizing McLean's formula. It was found that combined from bulk and/or surfaces causes much stronger...
Abstract Aluminium alloys are re-evaluated as most feasible way to satisfy the industrial needs of light-weight structural materials. However, unlike conventional metals such iron and titanium, aluminium does not have easily accessible secondary phases, which means that aluminium-based cannot be strengthened by harnessing multiple phases. This leaves age hardening only strengthening approach. Highly concentrated precipitates generated generally play a dominant role in shaping mechanical...
There is a pressing need to improve the ductility of magnesium alloys so that they can be applied as lightweight structural materials. In this study, mechanism for enhancing has been pursued using atomistic method. The generalized stacking fault (GSF) energies basal and prismatic planes in were calculated by density functional theory, effect GSF energy on dislocation core structures was examined semidiscrete variational Peierls–Nabarro model. Yttrium found have an anomalous influence...
Compared to cubic metals, whose primary slip mode includes twelve equivalent systems, the lower crystalline symmetry of hexagonal close-packed metals results in a reduced number slips and anisotropy plasticity, leading brittleness at ambient temperature. At higher temperatures, ductility improves owing activation secondary $⟨c+a⟩$ pyramidal systems. Thus, understanding fundamental properties corresponding dislocations is essential for improvement Here, we present large-scale ab initio...
The first sharp diffraction peak (FSDP) in the total structure factor has long been regarded as a characteristic feature of medium-range order (MRO) amorphous materials with polyhedron network, and its underlying structural origin is subject ongoing debate. In this study, we utilized machine learning molecular dynamics (MLMD) simulations to explore FSDP two typical high-density silica glasses: glass under pressure permanently densified glass. Our MLMD accurately reproduce properties glasses...
With the help of improved Monte Carlo renormalization-group scheme, we numerically investigate renormalization group flow antiferromagnetic Heisenberg and XY spin model on stacked triangular lattice (STA-model) its effective Hamiltonian, 2N-component chiral $\phi^4$ which is used in field-theoretical studies. We find that XY-STA with size $126\times 144 \times 126$ exhibits clear first-order behavior. also STA well reproduced by model, there are no fixed point for N=2 3 cases. This result...
From first-principles calculations, we estimated the trapping energy of hydrogen atom at interstitial site perfect crystals Mg2Si and Al7FeCu2 intermetallic compounds in aluminum matrix. We found that trapped atoms strongly, whereas did not. The highest is 0.56 eV/atom. also density can be increased up to about 13 atoms/nm3 while keeping high 0.40 inferred phase might remove from matrix, hence, preventing embrittlement alloy.
Solute clusters in long period stacking order (LPSO) alloys play a key role their idiosyncratic plastic behavior, for example kink formation and strengthening. Identifying atomistic details of cluster structures is prerequisite modeling LPSO crucial improving strength ductility; however, there much uncertainty regarding interstitial atoms the cluster. Although density functional theory calculations have shown that inclusion Mg energetically most favorable majority alloys, solute elements...
Molecular dynamics (MD) simulation is an important tool to understand the physical and chemical properties of cement hydrates at atomic level. MD with machine learning potential (MLP) considered a promising approach for accurate prediction material properties. However, applications multicomponent systems liquid–solid interface have been limited so far. In this work, we used artificial neural networks (ANNs) construct MLPs tobermorite minerals. Two were produced by optimization using...
First-principles calculations were employed to evaluate the trapping energy of a H atom in screw dislocation and an edge Al. After obtaining core structure absence H, we calculated at several tens possible sites its vicinity. The maximum energies 0.08 0.15 eV/atom for dislocations without zero-point vibrational correction, while they 0.11 0.18 with correction. calculation conditions present work correspond line density approximately 1.0 atom/nm along line, which is sufficiently low exclude...
Abstract Predicting materials properties of nuclear fuel compounds is a challenging task in science. Their thermodynamical behaviors around and above the operational temperature are essential for design reactors. However, they not easy to measure, because target range too high perform various standard experiments safely accurately. Moreover, theoretical methods such as first-principles calculations also suffer from computational limitations calculating due their calculation-costs complicated...
We attempted to calculate the hydrogen trapping energies at incoherent interfaces of MgZn2 precipitates and Mg2Si crystallites in aluminum alloys from first-principles calculations. Since unit cell containing interface does not satisfy periodic boundary condition, resulting a discontinuity crystal blocks, energy was calculated region far (vacuum) region. found considerable for atoms consisting assumed atomistic arrangement. also conducted preliminary calculations reduction cohesive by on matrix.
High-entropy alloys (HEAs) have received attention because of their excellent mechanical and thermodynamic properties. A recent study revealed that Co-free face-centered cubic HEAs could improve strength ductility, which is crucial for nuclear materials. Here we implemented first-principles calculations to explore the fundamental mechanism enhancing properties in Cr25Fe25Ni25Mn25 alloy. We found local lattice distortion HEA was more significant than well-known Cantor Furthermore, short-range...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetically Coupled Molecular System Composed of Organic Radicals with Different Spin MultiplicitiesAkira Izuoka, Masanori Fukada, Reiji Kumai, Mitsuhiro Itakura, Shinobu Hikami, and Tadashi SugawaraCite this: J. Am. Chem. Soc. 1994, 116, 6, 2609–2610Publication Date (Print):March 1, 1994Publication History Published online1 May 2002Published inissue 1 March...
Magnesium alloys are very promising structural material, especially because of their low density, but poor deformability at room temperature is making commercial application impractical. Some alloying elements have been shown to improve the ductility dramatically, and a search for yet better now pressing task. In this study, we investigated effects several on mechanical deformation behaviour magnesium using both first-principles calculations as well experiments. The indicate that influential...