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Tournier RF, Ojovan MI. NiTi 2, a New Liquid Glass. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6681. [PMID: 37895662 PMCID: PMC10608734 DOI: 10.3390/ma16206681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 09/25/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023]
Abstract
Many endothermic liquid-liquid transitions, occurring at a temperature Tn+ above the melting temperature Tm, are related to previous exothermic transitions, occurring at a temperature Tx after glass formation below Tg, with or without attached crystallization and predicted by the nonclassical homogenous nucleation equation. A new thermodynamic phase composed of broken bonds (configurons), driven by percolation thresholds, varying from ~0.145 to Δε, is formed at Tx, with a constant enthalpy up to Tn+. The liquid fraction Δε is a liquid glass up to Tn+. The solid phase contains glass and crystals. Molecular dynamics simulations are used to induce, in NiTi2, a reversible first-order transition by varying the temperature between 300 and 1000 K under a pressure of 1000 GPa. Cooling to 300 K, without applied pressure, shows the liquid glass presence with Δε = 0.22335 as memory effect and Tn+ = 2120 K for Tm = 1257 K.
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Affiliation(s)
- Robert F. Tournier
- UPR 3228 Centre National de la Recherche Scientifique, Laboratoire National des Champs Magnétiques Intenses, European Magnetic Field Laboratory, Institut National des Sciences Appliquées de Toulouse, Université Grenoble Alpes, F-31400 Toulouse, France;
| | - Michael I. Ojovan
- Department of Materials, Imperial College London, London SW7 2AZ, UK
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2
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Ojovan MI. The Flow of Glasses and Glass-Liquid Transition under Electron Irradiation. Int J Mol Sci 2023; 24:12120. [PMID: 37569496 PMCID: PMC10418639 DOI: 10.3390/ijms241512120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 07/22/2023] [Accepted: 07/26/2023] [Indexed: 08/13/2023] Open
Abstract
Recent discovery and investigation of the flow of glasses under the electron beams of transmission electron microscopes raised the question of eventual occurrence of such type effects in the vitrified highly radioactive nuclear waste (HLW). In connection to this, we analyse here the flow of glasses and glass-liquid transition in conditions of continuous electron irradiation such as under the e-beam of transmission electron microscopes (TEM) utilising the configuron (broken chemical bond) concept and configuron percolation theory (CPT) methods. It is shown that in such conditions, the fluidity of glasses always increases with a substantial decrease in activation energy of flow at low temperatures and that the main parameter that controls this behaviour is the dose rate of absorbed radiation in the glass. It is revealed that at high dose rates, the temperature of glass-liquid transition sharply drops, and the glass is fully fluidised. Numerical estimations show that the dose rates of TEM e-beams where the silicate glasses were fluidised are many orders of magnitude higher compared to the dose rates characteristic for currently vitrified HLW.
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Affiliation(s)
- Michael I. Ojovan
- Department of Materials, Imperial College London, London SW7 2AZ, UK;
- Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK
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Khan RAA, Luo M, Alsaad AM, Qattan IA, Abedrabbo S, Hua D, Zulfqar A. The Role of Polymer Chain Stiffness and Guest Nanoparticle Loading in Improving the Glass Transition Temperature of Polymer Nanocomposites. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1896. [PMID: 37446412 DOI: 10.3390/nano13131896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 07/15/2023]
Abstract
The impact of polymer chain stiffness characterized by the bending modulus (kθ) on the glass transition temperature (Tg) of pure polymer systems, as well as polymer nanocomposites (PNCs), is investigated using molecular dynamics simulations. At small kθ values, the pure polymer system and respective PNCs are in an amorphous state, whereas at large kθ values, both systems are in a semicrystalline state with a glass transition at low temperature. For the pure polymer system, Tg initially increases with kθ and does not change obviously at large kθ. However, the Tg of PNCs shows interesting behaviors with the increasing volume fraction of nanoparticles (fNP) at different kθ values. Tg tends to increase with fNP at small kθ, whereas it becomes suppressed at large kθ.
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Affiliation(s)
- Raja Azhar Ashraaf Khan
- Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Mengbo Luo
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Ahmad M Alsaad
- Department of Physics, Jordan University of Science & Technology, P.O. Box 3030, Irbid 22110, Jordan
| | - Issam A Qattan
- Department of Physics, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi 127788, United Arab Emirates
| | - Sufian Abedrabbo
- Department of Physics, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi 127788, United Arab Emirates
| | - Daoyang Hua
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Afsheen Zulfqar
- Department of Physics, Zhejiang Normal University, Jinhua 321004, China
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4
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Abrosimova G, Gunderov D, Postnova E, Aronin A. Changes in the Structure of Amorphous Alloys under Deformation by High-Pressure Torsion and Multiple Rolling. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1321. [PMID: 36770327 PMCID: PMC9920891 DOI: 10.3390/ma16031321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/02/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
X-ray diffraction and scanning electron microscopy were used to study changes in the structure of amorphous alloys under deformation by high-pressure torsion and multiple rolling. The change in mean nearest neighbor distance (the radius of the first coordination sphere) under deformation was determined. During deformation, shear bands are formed in amorphous alloys, which are regions of lower density compared to the surrounding undeformed amorphous matrix. Shear bands are zones of increased free volume, in which crystallization processes are facilitated. The change in the proportion of free volume under deformation of various types was estimated. The formation of shear bands leads to the appearance of steps on the surface of the samples. The number of shear bands and the surface morphology of deformed amorphous alloys were determined by the type of deformation and the physical properties of the material. The results obtained are discussed within the concept of free volume in the amorphous phase.
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Affiliation(s)
- Galina Abrosimova
- Osipyan Institute of Solid State Physics RAS, 142432 Chernogolovka, Russia
| | - Dmitry Gunderov
- Ufa Federal Research Center RAS, Institute of Molecule and Crystal Physics, 450075 Ufa, Russia
| | - Evgenia Postnova
- Osipyan Institute of Solid State Physics RAS, 142432 Chernogolovka, Russia
| | - Alexandr Aronin
- Osipyan Institute of Solid State Physics RAS, 142432 Chernogolovka, Russia
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Louzguine-Luzgin DV. Structural Changes in Metallic Glass-Forming Liquids on Cooling and Subsequent Vitrification in Relationship with Their Properties. MATERIALS (BASEL, SWITZERLAND) 2022; 15:7285. [PMID: 36295350 PMCID: PMC9610435 DOI: 10.3390/ma15207285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 09/30/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
The present review is related to the studies of structural changes observed in metallic glass-forming liquids on cooling and subsequent vitrification in terms of radial distribution function and its analogues. These structural changes are discussed in relationship with liquid's properties, especially the relaxation time and viscosity. These changes are found to be directly responsible for liquid fragility: deviation of the temperature dependence of viscosity of a supercooled liquid from the Arrhenius equation through modification of the activation energy for viscous flow. Further studies of this phenomenon are necessary to provide direct mathematical correlation between the atomic structure and properties.
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Affiliation(s)
- D. V. Louzguine-Luzgin
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Aoba-Ku, Sendai 980-8577, Japan;
- MathAM-OIL, National Institute of Advanced Industrial Science and Technology (AIST), Sendai 980-8577, Japan
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Bolmatov D. The Phonon Theory of Liquids and Biological Fluids: Developments and Applications. J Phys Chem Lett 2022; 13:7121-7129. [PMID: 35950307 DOI: 10.1021/acs.jpclett.2c01779] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Among the three basic states of matter (solid, liquid, and gas), the liquid state has always eluded general theoretical approaches for describing liquid energy and heat capacity. In this Viewpoint, we derive the phonon theory of liquids and biological fluids stemming from Frenkel's microscopic picture of the liquid state. Specifically, the theory predicts the existence of phonon gaps in vibrational spectra of liquids and a thermodynamic boundary in the supercritical state. Direct experimental evidence reaffirming these theoretical predictions was achieved through a combination of techniques using static compression X-ray diffraction and inelastic X-ray scattering on deeply supercritical argon in a diamond anvil cell. Furthermore, these findings inspired and then led to the discovery of phonon gaps in liquid crystals (mesogens), block copolymers, and biological membranes. Importantly, phonon gaps define viscoelastic crossovers in cellular membranes responsible for lipid self-diffusion, lateral molecular-level stress propagation, and passive transmembrane transport of small molecules and solutes. Finally, molecular interactions mediated by external stimuli result in synaptic activity controlling biological membranes' plasticity resulting in learning and memory. Therefore, we also discuss learning and memory effects─equally important for neuroscience as well as for the development of neuromorphic devices─facilitated in biological membranes by external stimuli.
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Affiliation(s)
- Dima Bolmatov
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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Molecular Dynamics Simulation of Bulk Cu Material under Various Factors. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12094437] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In this paper, the molecular dynamics (MD) method was used to study the influence of factors of bulk Cu material, such as the effect of the number of atoms (N) at temperature (T), T = 300 K, temperature T, and annealing time (t) with Cu5324 on the structure properties, phase transition, and glass temperature Tg of the bulk Cu material. The obtained results showed that the glass transition temperature (Tg) of the bulk Cu material was Tg = 652 K; the length of the link for Cu-Cu had a negligible change; r = 2.475 Å; and four types of structures, FCC, HCP, BCC, Amor, always existed. With increasing the temperature the FCC, HCP, and BCC decrease, and Amorphous (Amor) increases. With an increasing number of atoms and annealing time, the FCC, HCP, and BCC increased, and Amor decreased. The simulated results showed that there was a great influence of factors on the structure found the gradient change, phase transition, and successful determination of the glass temperature point above Tg of the bulk Cu material. On the basis of these results, essential support will be provided for future studies on mechanical, optical, and electronic properties.
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