Article
Materials Science, Multidisciplinary
Mugilgeethan Vijendran, Ryosuke Matsumoto
Summary: Plastic deformation and hydrogen presence enhance the concentration of vacancy-type defects in alpha-iron, leading to the formation of planar vacancy clusters (VCs) and prismatic dislocation loops (PDLs). The formation and conversion of VCs and PDLs influences the mechanical properties of iron-based materials. A quantitative energy barrier for the transition between nano-sized PDLs and VCs has been established, showing that VCs with a cluster size of more than 19 vacancies easily nucleate into PDLs in alpha-iron.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Miaosen Yu, Ziqiang Wang, Fei Wang, Wahyu Setyawan, Xuehao Long, Yong Liu, Limin Dong, Ning Gao, Fei Gao, Xuelin Wang
Summary: The segregation behavior of Cr and Al atoms to a prismatic dislocation loop in a Fe-Cr-Al alloy is investigated using molecular dynamics method and ab initio energy calculation. The results show that Cr can segregate to the loops, while Al atoms cannot segregate by themselves. However, the presence of segregated Cr atoms can promote Al segregation, resulting in a coupled segregation of Cr and Al. Furthermore, the pinning behavior of the dislocation loop to an edge dislocation motion can be affected by Al segregation through the coupled segregation process.
Article
Engineering, Mechanical
Long Guo, Liang Wang, Ning Gao, Yangchun Chen, Beibei Liu, Wangyu Hu, Shifang Xiao, Kun Wang, Fei Gao, Huiqiu Deng
Summary: Tungsten is a promising candidate material for future fusion reactors. The study finds that the habit plane and plasticity of tungsten with a 1/2 < 111 > crystallographic orientation are strongly influenced by shock waves. A new rotation mechanism is proposed to predict the changing trend of the habit plane of dislocation loops.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Engineering, Mechanical
Marion Borde, Laurent Dupuy, Adrien Pivano, Bruno Michel, David Rodney, Jonathan Amodeo
Summary: In this study, the plasticity of irradiated UO2 is investigated using molecular dynamics and discrete dislocation dynamics simulations. The interactions between irradiation loops and glissile dislocations are studied, and the effects of these interactions on the strengthening of UO2 are characterized. The collective behavior of irradiation defects and the formation of clear bands in UO2 fuel at high temperature are also discussed.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Multidisciplinary Sciences
O. El Atwani, H. T. Vo, M. A. Tunes, C. Lee, A. Alvarado, N. Krienke, J. D. Poplawsky, A. A. Kohnert, J. Gigax, W. -Y Chen, M. Li, Y. Q. Wang, J. S. Wrobel, D. Nguyen-Manh, J. K. S. Baldwin, O. U. Tukac, E. Aydogan, S. Fensin, E. Martinez
Summary: The authors develop an irradiation resistant, thermally stable, and strong refractory high entropy alloy (RHEA) for nuclear application through a combination of simulation and experiments. This research is of great significance in the quest for new materials that can withstand severe irradiation and mechanical extremes for advanced applications.
NATURE COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Guanze He, Hongbing Yu, Phani Karamched, Junliang Liu, Felix Hofmann
Summary: Elastic interactions play a crucial role in controlling irradiation damage evolution, yet experimental investigation on this topic is largely lacking. In this study, we used transmission electron microscopy and high-resolution on-axis transmission Kikuchi diffraction techniques to study the correlation between the evolution of irradiation-induced damage structures and the associated lattice strains in self-ion irradiated pure tungsten. The results revealed different dislocation loop structures depending on the sample thickness, indicating that free surfaces restrict the formation of extended defect structures observed in thicker samples. Strain analysis using high-resolution Kikuchi diffraction demonstrated the formation of crystallographically-oriented long-range strain fluctuations above 0.01 dpa and a decrease in total elastic energy above 0.1 dpa.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
J. Wu, F. Granberg
Summary: Tungsten is chosen as the material for demanding parts in fusion test reactors and power plants. Material degradation due to irradiation necessitates component replacement. Understanding how defects are formed is crucial for predicting replacement needs. Low energy simulations and Frenkel-pair insertion method are compared to investigate the potential of the latter in accelerating cascade simulations. Results show similarities qualitatively, but differences quantitatively, particularly at higher energies.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Junye Li, Xiwei Dong, Hongcai Xie, Chengyu Xu, Jianhe Liu, Jingran Zhang
Summary: This paper investigates the influence of microstructure and mechanics of titanium aluminum alloy on its machining performance. By constructing a molecular dynamics model, the formation of sub-surface defect layer and the evolution mechanism of prismatic dislocation loop during nano-cutting process are analyzed. In addition, nano-indentation simulation is conducted to study the effect of process-induced sub-surface defect structure on the mechanical properties of the material. The results show that the original defect structure can increase the hardness of the material.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Jiaqi Duan, Haiming Wen, Li He, Kumar Sridharan, Andrew Hoffman, Maalavan Arivu, Xiaoqing He, Rinat Islamgaliev, Ruslan Valiev
Summary: The study found that nanocrystalline G91 steel has higher resistance to irradiation-induced defect formation and lower irradiation-induced hardening compared to fine-grained and ultrafine-grained G91.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Mohammad Bany Salman, Minkyu Park, Mosab Jaser Banisalman
Summary: In this study, we used molecular dynamics simulations to investigate the impact of strain on defect formation and interstitial dislocation loop (IDL) development in pure tantalum and Ta-20 W alloy systems. The results showed that the number of Frenkel pairs (FPs) and self-interstitial atom (SIA) clusters increased with tensile strain and decreased with compressive strain, with the alloy system exhibiting lower numbers compared to pure tantalum. Additionally, the applied strain reduced the barrier for IDL formation. This study highlights the importance of considering strain and alloying effects in radiation-damaged environments.
METALS AND MATERIALS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Mugilgeethan Vijendran, Ryosuke Matsumoto, Shinya Taketomi
Summary: This study comprehensively analyzed the diffusion behavior of vacancy-type dislocation loops at different temperatures using molecular dynamics simulations. It was found that the activation energy of diffusion increased with decreasing loop size for small loops, while it remained almost constant for larger loops. This behavior was associated with the tensile stress produced by the opposing edge dislocation segment and the change of dislocation core structure.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Ping Zhou, Fei Shuang, Rong-Hao Shi
Summary: This paper investigates the mechanisms of nucleation and propagation of prismatic dislocation loop (PDL) arrays in single-crystal medium-entropy CrCoNi alloys and pure Ni using molecular dynamics simulations. The findings reveal size-dependent plasticity in both Ni and CrCoNi samples, although it is less pronounced in CrCoNi samples. PDLs in CrCoNi alloys are often trapped in stable pileups, resulting in a significant strengthening effect, whereas PDLs in Ni configurations glide easily and exit freely.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
A. Fellman, A. E. Sand
Summary: This study investigates the effect of different primary recoil energies on defect formation in tungsten through molecular dynamics simulations. It is found that pre-existing radiation-induced defects modify the number of additional defects formed during cascades. Furthermore, the formation of dislocation loops in cascades is more dependent on the size of pre-existing voids rather than the energy of the primary recoil.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Chemistry, Physical
Zhiwei Zhang, Qiang Fu, Jun Wang, Rong Yang, Pan Xiao, Fujiu Ke, Chunsheng Lu
Summary: This study reveals a novel interaction between planar defects and complex dislocation structures in Ni3Al, with the prismatic dislocation loop pairs appearing in a butterfly-like shape. The planar defects effectively hinder the movement of the dislocation loops, with twinning boundaries being the strongest impediment. The findings provide valuable insights for the nanostructured design of materials with superior mechanical properties.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Geochemistry & Geophysics
Emily M. Peterman, Steven M. Reddy, David W. Saxey, Denis Fougerouse, M. Zakaria Quadir, Michael J. Jercinovic
Summary: The study analyzed untreated and experimentally heated Archean zircons, revealing the formation of clustered structures in the heated zircon similar to those observed in natural geological processes. The differences in cluster distribution between experimentally heated and geologically affected zircons are determined by radiation dose, pressure-temperature-time history, and zircon composition. These findings provide insight into the significance of clustered trace elements and their isotopic characteristics in zircon.
AMERICAN MINERALOGIST
(2021)
Article
Nanoscience & Nanotechnology
Roman Groger, Zdenek Chlup, Tereza Kubenova
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2018)
Review
Materials Science, Multidisciplinary
Roman Groger, Zdenek Chlup, Tereza Kubenova, Ivo Kubena
JOURNAL OF MATERIALS RESEARCH
(2019)
Article
Materials Science, Multidisciplinary
Roman Groger, Vaclav Vitek
COMPUTATIONAL MATERIALS SCIENCE
(2019)
Article
Crystallography
Martin Friak, Vilma Bursikova, Nadezda Pizurova, Jana Pavlu, Yvonna Jiraskova, Vojtech Homola, Ivana Mihalikova, Anton Slavik, David Holec, Monika Vsianska, Nikola Koutna, Jan Fikar, Dusan Janickovic, Mojmir Sob, Jorg Neugebauer
Article
Instruments & Instrumentation
Jan Fikar, Robin Schaeublin
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2020)
Article
Engineering, Mechanical
Roman Groger, Vaclav Vitek
INTERNATIONAL JOURNAL OF PLASTICITY
(2020)
Article
Materials Science, Multidisciplinary
R. Groger, V. Vitek, A. Dlouhy
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2020)
Article
Materials Science, Multidisciplinary
Zdenek Antos, Petr Vacek, Roman Groger
COMPUTATIONAL MATERIALS SCIENCE
(2020)
Article
Materials Science, Multidisciplinary
Roman Groger, Jiri Sremr, Jana Vydrova
Summary: The simplified models of thermally activated dislocation glide serve as an important connection between atomic-level studies of isolated dislocations and macroscopic thermodynamic properties of materials. By minimizing the activation enthalpy and solving for the shape of the dislocation line, a unique activated state of the dislocation can be defined, showing that the shape of the dislocation changes with applied stress to maintain the state of minimum activation enthalpy.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2021)
Article
Physics, Applied
Petr Vacek, Martin Frentrup, Lok Yi Lee, Fabien C. P. Massabuau, Menno J. Kappers, David J. Wallis, Roman Groeger, Rachel A. Oliver
Summary: The defect structure of zincblende GaN nucleation layers grown on 3C-SiC/Si (001) was investigated, which includes perfect dislocations, partial dislocations, and stacking faults. These defects, especially perfect and partial dislocations, help relieve the compressive lattice mismatch strain in GaN layers. The stacking faults in the layers are mainly bounded by 30 degrees Shockley partial dislocations and occasionally by Lomer-Cottrell partial dislocations, originating from the dissociation of perfect dislocations or direct nucleation of partial dislocations loops from the surface.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Engineering, Mechanical
Roman Groger
Summary: This study demonstrates the invariance of yield criteria in determining plastic deformation onset in crystalline materials under inversion symmetry, as well as the specific yield criterion for non-Schmid materials. The model is applied to body-centered cubic and hexagonal close-packed metals to show the significance of non-Schmid stress terms in predicting yielding onset. In the special case where all non-Schmid stresses vanish, the model simplifies to Tresca's maximum shear stress theory.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Nanoscience & Nanotechnology
Lucia Bajtosova, Barbora Krivska, Rostislav Kralik, Jozef Vesely, Jan Hanus, Petr Harcuba, Jan Fikar, Ankit Yadav, Miroslav Cieslar
Summary: This study used molecular dynamics simulation method to investigate the mechanical properties of thin aluminum-based films, and compared the results with transmission electron microscope experiments. The simulation results matched well with the experimental results, revealing the importance of grain boundary processes in deformation.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Roman Groger
Summary: A study has found that the phenomenon of anomalous slip in transition metals is closely related to the stability of screw junctions between dislocations. In most bcc metals, these junctions do not break under stress and the dislocations can only move on common crystal planes. However, in alkali metals, tantalum, and iron, the application of stress causes the dislocations to unzip and further glide on predicted planes. These results provide an explanation for the experimentally observed anomalous slip and suggest a reason for its increased propensity in later stages of plastic deformation.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
Zachary T. Kloenne, Jean-Philippe Couzinie, Milan Heczko, Roman Groger, Gopal B. Viswanathan, William A. T. Clark, Hamish L. Fraser
Summary: A refined microstructure consisting of bcc precipitates embedded in an ordered B2 matrix has been observed in the refractory high entropy alloy AlMo0.5NbTa0.5TiZr, resembling an inverted superalloy-like micro-structure. Coarsening of the microstructure occurs after aging, resulting in a faceted interface. Misfit dislocations at the interface were observed on the {110} interface plane, extending into the bcc phase, and no lattice invariant deformation normal to the primary {110} planes was observed, indicating a pure expansion transformation between the B2 and bcc phases.
SCRIPTA MATERIALIA
(2023)
Article
Nuclear Science & Technology
Jan Fikar, Robin Schaublin, Daniel R. Mason, Duc Nguyen-Manh
NUCLEAR MATERIALS AND ENERGY
(2018)
Article
Instruments & Instrumentation
Taisei Hayashi, Kensei Ichiba, Daisuke Nakauchi, Takumi Kato, Noriaki Kawaguchi, Takayuki Yanagida
Summary: In this study, Cr-doped Mg4Ta2O9 single crystals with different doping levels were synthesized using the floating zone method, and their photoluminescence and scintillation properties were evaluated. The results showed that Cr-doped Mg4Ta2O9 single crystals exhibited broad emission bands in the near-infrared region and showed scintillation characteristics within specific wavelength ranges. Additionally, the samples with different Cr doping levels demonstrated different lower detection limits based on the dose rate response function.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2024)
Article
Instruments & Instrumentation
S. Marouf, A. C. Chami, Y. Boudouma
Summary: This study develops a Monte Carlo simulation approach to describe proton-induced secondary electron emission in solids. Theoretical modeling based on the Mott's elastic scattering cross-section and Lindhard's dielectric function was used to calculate the double differential cross-section (DDCS) of excited electrons and describe electron transport in the medium. The results for aluminum show the angular and energy distributions of backscattered electrons for incident protons with energy below 25 keV at normal incidence, and the total electron emission yield also agrees well with available measurements.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2024)
Article
Instruments & Instrumentation
Weipeng Yan, Baojun Duan, Zijian Zhu, Yan Song, Guzhou Song, Jiming Ma, Binkang Li, Yucheng Liu
Summary: This article reports on the scintillation performance of Lithium-doped 2D (PEA)2PbBr4 perovskite single crystals synthesized at room temperature. The crystals exhibit fast decay time, high light yield, and high spatial resolution, making them highly promising for medical diagnostic applications.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2024)
Article
Instruments & Instrumentation
S. B. Vishwakarma, S. K. Dubey, R. L. Dubey, I. Sulania, D. Kanjilal
Summary: Investigations have been conducted on the implanted SiO2 thin film after thermal annealing using various analytical techniques. The results revealed the absence of vacancy defects, variations in vibrational modes and the formation of new structures. The photoluminescence intensity of the annealed SiO2 samples was higher, with a decrease in non-radiative defect centers and an increase in radiative Si:SiO2 interface states. Additionally, the presence of silicon nanoclusters formed after annealing resulted in an additional radiative recombination peak. Furthermore, the formation of new SiOx structures was observed after thermal annealing.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2024)
Article
Instruments & Instrumentation
M. Koshimizu, S. Kurashima, A. Kimura, M. Taguchi
Summary: By observing the scintillation time profiles of CeF3 under irradiations of pulsed beams with different LETs, we found that the initial decay was faster for higher LET, which is consistent with previous studies on other self-activated scintillators. This faster decay at higher LET can be explained by the competition between the scintillation caused by 5d-4f transition of Ce3+ ions and quenching due to the interaction between excited Ce3+ ions close to each other.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2024)
Article
Instruments & Instrumentation
Junjie Shi, Jianhong Hao, Fang Zhang, Qiang Zhao, Bixi Xue, Jieqing Fan, Zhiwei Dong
Summary: This study examined the neutralization process and beam quality of a hydrogen beam by emitting negative hydrogen ions to a hydrogen target. The findings showed that the neutralization efficiency was influenced by variables such as the transport distance, energy, and target gas density. However, the maximal neutralization efficiency was not affected by the density of the target gas or the energy of the negative hydrogen ions.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2024)