Article
Materials Science, Multidisciplinary
Simon C. Middleburgh, William E. Lee, Michael J. D. Rushton
Summary: Amorphous uranium dioxide has been modeled on the atomic scale using a combination of quantum mechanical and classical forcefield methods, revealing structures consistent with experimental patterns. Non-stoichiometry is accommodated more readily in the amorphous system, with a predicted spin-glass magnetic structure and a computed surface energy similar to grain boundary bubbles in UO2.
Article
Physics, Applied
M. Baloi, D. Wamwangi, B. A. Mathe, R. M. Erasmus, D. G. Billing, M. Madhuku, P. Sechogela
Summary: This study investigated the elastic properties and lattice thermal conductivity of amorphous Ge2Sb2Te5 and GeTe thin films using surface Brillouin scattering. It was found that GeTe exhibited acoustic hardening compared to Ge2Sb2Te5, leading to lower lattice thermal conductivities for both chalcogenides alloys. This could have practical applications in thermal management for phase-change memory devices and thermoelectric applications.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Jiangbo Tang, A. Ahmadi, As'ad Alizadeh, Reza Abedinzadeh, Azher M. Abed, Ghassan Fadhil Smaisim, Salema K. Hadrawi, Navid Nasajpour-Esfahani, Davood Toghraie
Summary: Metal matrix composites with nano-particle reinforcement have unique mechanical and thermal properties, making them suitable for various structural and thermal applications. In this study, molecular dynamics simulation was used to model and investigate the effects of reinforcing nano-particles on the hardness of aluminium-based composites. The results showed an increase in hardness with the addition of nanoparticles, and the analysis of the radial distribution function confirmed the proper balance of the simulated atomic systems. These findings have practical implications for the use of aluminium-based composites in industrial, engineering, and medical fields.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Multidisciplinary Sciences
Jin Shi, Zhengxiang Huang, Xudong Zu, Qiangqiang Xiao, Yuting Wang
Summary: The formation of a Zr-based amorphous alloy shaped charge jet and the suitability of different numerical algorithms were investigated through experiments and numerical simulations. X-ray experiments were conducted to study the characteristics of the jet. The Euler and SPH algorithms were compared and analyzed using the Autodyn hydrocode. The results showed high accuracy in determining the jet velocity for both algorithms. The improved Johnson-Holmquist constitutive model (JH-2) was found to be suitable for the Zr-based amorphous alloy.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Ceramics
Yuchen Liu, Yu Zhou, Zhihua Yang, Daxin Li, Dechang Jia, Bin Liu
Summary: Density-modified structural features and mechanical properties of amorphous Si2BC3N were investigated using ab initio molecular dynamics simulations. The chemical bonds of Si2BC3N were found to be unaffected by density changes, with only minor alterations in bond lengths, peak positions in density of states, and Bader charge values. However, the composition of chemical bonds was altered. Under high-density conditions, the polyhedral units of Si2BC3N transitioned from a sp(2)-like trigonal configuration to a tetrahedral configuration, particularly for B, C, and N. This structural response mechanism was different from the stretching or shrinking of bonds observed in crystals. The increased tetrahedron content improved the amorphous structure stability of Si2BC3N, inhibiting the separation of turbostratic BN(C) and enhancing the second-order elastic constants, elastic moduli, and tensile/shear strengths. While high density may reduce the debonding capability of the fiber/Si2BC3N interface, it will not affect the preference for crack deflection at interfaces. These findings suggest the potential for optimizing the mechanical properties of SiBCN ceramics through density tailoring in experiments.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Physics, Fluids & Plasmas
Ivan Kriuchevskyi, Timothy W. Sirk, Alessio Zaccone
Summary: In this study, a mathematical description of amorphous solid deformation and plasticity is presented by extending the concept of instantaneous normal modes (INMs) to deformed systems. The linear response theory is formulated by considering the strain-dependent tangent modulus, and the prediction shows good agreement with simulations.
Article
Chemistry, Physical
Ricardo Paupitz, Tales J. da Silva, Marilia J. Caldas, Douglas S. Galvao, Alexandre F. Fonseca
Summary: A new auxetic structure called A gamma G, based on a gamma-graphyne structure, is proposed and investigated for its structural, mechanical, electronic properties, and thermal stability using classical and quantum molecular dynamics simulations. The results show that A gamma G has a bandgap larger than 1.6 eV and remains thermally stable at a wide range of temperatures. Both classical and quantum simulations confirm the auxetic behavior of A gamma G when isolated or deposited on a copper substrate. This study suggests that A gamma G is one of the densest auxetic structures among the graphyne-like families.
CHEMICAL PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
I. M. Van Meerbeek, J. M. Lenhardt, W. Small, T. M. Bryson, E. B. Duoss, T. H. Weisgraber
Summary: This article examines the compression behavior of Bouligand structures, and finds that elastomeric Bouligand structures can increase lattice stress by over 300% without altering porosity. Path length metrics are introduced to explain the relationship between layer rotation and compression response.
Article
Multidisciplinary Sciences
Elham Sharifikolouei, Baran Sarac, Yonghui Zheng, Piotr Bala, Jurgen Eckert
Summary: Metallic glasses have gained attention for their hardness and corrosion resistance. A new method has been proposed to fabricate metallic glass microfibers using commercially available alloy compositions. The microfibers show significantly increased hardness and further enhancement of strength through heat treatment.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Applied
Ying-Xian Shi, Shen-Hui Li, Zhi-Ping Zhao
Summary: The dissolution behavior of cellulose acetate (CA) is a critical property for its wide range of applications and derivative preparations. This study proposes a molecular model building strategy to investigate the dissolution behavior and structural properties of CA using molecular dynamics simulation and density functional theory. The findings suggest that an increase in substituents reduces the cohesive energy and polarity of CA, thereby enhancing its solubility. The interaction of solvent molecules and the diffusion coefficient also play a synergistic role in CA dissolution.
CARBOHYDRATE POLYMERS
(2022)
Article
Chemistry, Multidisciplinary
Nataliya A. Sakharova, Jorge M. Antunes, Andre F. G. Pereira, Bruno M. Chaparro, Jose Fernandes
Summary: This study focuses on the elastic properties of non-carbon nanotubes based on compounds of the 13th group of the periodic table. The research reveals that these nanotubes are more suitable candidates than carbon nanotubes for building novel nano-devices, and proposes a robust methodology to calculate the surface elastic moduli of phosphide nanotubes.
Article
Pharmacology & Pharmacy
Xiaoping Fang, Yi Hu, Guangyi Yang, Wenfeng Shi, Shan Lu, Yan Cao
Summary: Co-amorphous formation, a new technology in the pharmaceutical field, can improve the solubility, dissolution, and stability of poorly water-soluble drugs. This study successfully designed three stable ternary co-amorphous systems to enhance the physicochemical properties of the binary co-amorphous system and demonstrated the impact of co-former's pKa value on the ternary co-amorphous system. The ternary co-amorphous systems showed increased solubility, improved dissolution behavior, and maintained good physical stability for 18 months.
EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS
(2022)
Article
Chemistry, Physical
Chao Yang, Yong-chao Liang, Li-li Zhou, Qian Chen, Bei Wang, Li Zhang, Jia-jun Ma, Ting-hong Gao, Quan Xie
Summary: In recent years, it has been demonstrated that crystal/amorphous composites (CAC) with high strength and ductility can be developed by combining high-entropy alloys and metallic glasses (HE-MGs). This paper simulates the rapid solidification of CoNiCrFeMn using molecular dynamics simulations to obtain HE-MGs, and then adds holes of different sizes for uniaxial tension. The results show that larger holes have better plasticity, but this comes at the cost of decreased strength and hardness. By considering strength and plasticity, CoNiCrFeMn HE-MGs with a hole radius of 7.06 angstrom are selected to examine the effect of crystal layer thickness on the mechanical properties of CAC.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Anna Kus, Wirginia Pilarczyk, Aleksandra Malachowska, Andrzej Ambroziak, Piotr Gebara
Summary: The properties of Co-based alloys with high Glass Forming Ability in the form of powder are not widely known, but they are often used for developing bulk metallic glasses. In this study, Co-based alloys were developed by gas-atomization method, resulting in spherical and chemically homogeneous powder particles. Annealing increased mechanical properties such as hardness and elastic module due to crystallization, and revealed that one alloy is soft magnetic while the other is semi-hard magnetic material.
Article
Materials Science, Multidisciplinary
Zhengyang Zhang, Hanxing Zhu, Ru Yuan, Sanmin Wang, Tongxiang Fan, Yacine Rezgui, Di Zhang
Summary: This paper investigates the elastic properties of IPCs reinforced by different types of regular lattice fiber networks and finds that the Young's modulus of IPCs is larger when the constituent materials have a larger difference in Poisson's ratios and a smaller difference in Young's moduli. It also demonstrates that structural hierarchy can enhance the stiffness of IPCs by 30%. Additionally, these IPCs exhibit almost isotropic Young's modulus, different Poisson's ratios, and are easy to manufacture with high Young's moduli.
MATERIALS & DESIGN
(2022)
Article
Materials Science, Multidisciplinary
Nikolai V. Priezjev
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2020)
Article
Materials Science, Ceramics
Nikolai V. Priezjev
Summary: This study investigates the influence of static stress and alternating loading direction on the potential energy and mechanical properties of amorphous alloys using molecular dynamics simulations. It was found that at sufficiently large values of static stress, the binary glass becomes rejuvenated through collective, irreversible rearrangements of atoms. Including additional static stress orientation in the loading protocol amplifies the rejuvenation effect, leading to improvements in the mechanical properties of metallic glasses.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2021)
Article
Materials Science, Multidisciplinary
Nikolai V. Priezjev
Summary: This study uses molecular dynamics simulations to investigate the effect of tensile stress applied during cooling of binary glasses on potential energy states and mechanical properties. The results show that higher applied stress can enhance potential energy and improve the plasticity of glasses. Additionally, the amorphous structure of rejuvenated glasses characterized by an increase in the number of contacts between smaller type atoms can enhance ductility in glasses prepared at larger applied stresses and higher initial temperatures.
Article
Materials Science, Ceramics
Nikolai V. Priezjev
Summary: The research revealed that the potential energy and mechanical properties of amorphous materials can be influenced by variable-amplitude loading. Proper loading can rejuvenate well-annealed glasses, while improper loading can lead to a gradual decrease in energy states of poorly annealed glasses.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2021)
Article
Materials Science, Ceramics
Nikolai V. Priezjev
Summary: This study investigates the effect of small-amplitude periodic shear on annealing of a shear band in binary glasses through molecular dynamics simulations. The results show that increasing strain amplitude leads to glasses being relocated to deeper potential energy levels, and mechanical tests demonstrate an increase in shear modulus and yield stress with loading at strain amplitudes close to the yield strain.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2021)
Article
Materials Science, Multidisciplinary
Nikolai V. Priezjev
Summary: The research found that with increasing glass stability, the shear modulus and yielding peak of periodically deformed binary glasses increase towards plateau levels, and the yielding transition occurs at higher amplitudes and becomes more abrupt. The initiation and formation processes of shear bands are elucidated through spatiotemporal analysis of nonaffine displacements.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Clinical Neurology
Nikolai Priezjev, Francisco G. Vital-Lopez, Jaques Reifman
Summary: This study assessed the ability of biomathematical models to predict alertness impairment and found that these models have high accuracy in predicting alertness decline at both the group-average and individual levels. The results indicate that in three out of four psychomotor vigilance tests, it is difficult to distinguish between study data and model predictions.
JOURNAL OF SLEEP RESEARCH
(2023)
Article
Materials Science, Ceramics
Nikolai V. Priezjev
Summary: Molecular dynamics simulations were used to investigate the effect of cyclic shear deformation on structural relaxation and yielding in binary glasses. It was found that mechanical annealing occurred through intermittent plastic rearrangements, with the spatial extent decreasing as energy levels decreased. The yielding behavior was studied by adjusting strain amplitude, and it was observed that the critical strain amplitude remained constant regardless of the initial energy level. The formation of a shear band at the yielding transition was correlated with an increase in the number of atoms with large nonaffine displacements.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2022)
Article
Mechanics
Liuzhen Ren, Haibao Hu, Luyao Bao, Nikolai V. Priezjev, Jun Wen, Luo Xie
Summary: The study on the liquid-liquid interface at liquid-infused surfaces reveals different local slip modes under different viscosity ratios and elucidates the impact of viscosity ratio on effective slip length. The results may serve as a guide for optimizing the design of liquid-infused surfaces with enhanced slip properties.
Article
Materials Science, Ceramics
Pritam Kumar Jana, Nikolai Priezjev
Summary: The influence of cyclic loading and glass stability on structural relaxation and yielding transition in amorphous alloys was investigated using molecular dynamics simulations. It was found that rapidly cooled glasses under asymmetric cyclic shear gradually evolve towards states with lower potential energy and finite stress at zero strain. The yielding transition in more stable glasses can be delayed for hundreds of cycles when the strain amplitude is near a critical value.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Nikolai V. Priezjev
Summary: The study investigates the accumulation of plastic deformation and flow localization in amorphous alloys under periodic shear using molecular dynamics simulations. A well-annealed binary mixture of one million atoms subjected to oscillatory shear deformation with strain amplitudes slightly above a critical value is studied. The results show that the number of shear cycles until the yielding transition can be described by a power-law function when approaching a critical strain amplitude. The analysis of nonaffine displacements of atoms elucidates the process of strain localization, leading to the formation of a system-spanning shear band.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Nikolai V. Priezjev
Summary: This study investigates the effect of oscillatory shear deformation on fatigue life, yielding transition, and flow localization in metallic glasses using molecular dynamics simulations. The research reveals that at strain amplitudes below a critical value, plastic events are highly localized, while above the critical point, plastic deformation gradually accumulates until yielding transition and shear band formation across the system. Interestingly, when the strain amplitude approaches the critical value from above, the number of cycles to failure increases as a power-law function.
Meeting Abstract
Clinical Neurology
Jaques Reifman, Francisco Vital-Lopez, Nikolai Priezjev
Article
Materials Science, Ceramics
Nikolai Priezjev
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2020)
Article
Materials Science, Multidisciplinary
Anish Thomas, Nikolai V. Priezjev
COMPUTATIONAL MATERIALS SCIENCE
(2020)