Download or read book Atomistic Simulations of Glasses written by Jincheng Du and published by John Wiley & Sons. This book was released on 2022-04-05 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete reference to computer simulations of inorganic glass materials In Atomistic Simulations of Glasses: Fundamentals and Applications, a team of distinguished researchers and active practitioners delivers a comprehensive review of the fundamentals and practical applications of atomistic simulations of inorganic glasses. The book offers concise discussions of classical, first principles, Monte Carlo, and other simulation methods, together with structural analysis techniques and property calculation methods for the models of glass generated from these atomistic simulations, before moving on to practical examples of the application of atomistic simulations in the research of several glass systems. The authors describe simulations of silica, silicate, aluminosilicate, borosilicate, phosphate, halide and oxyhalide glasses with up-to-date information and explore the challenges faced by researchers when dealing with these systems. Both classical and ab initio methods are examined and comparison with experimental structural and property data provided. Simulations of glass surfaces and surface-water reactions are also covered. Atomistic Simulations of Glasses includes multiple case studies and addresses a variety of applications of simulation, from elucidating the structure and properties of glasses for optical, electronic, architecture applications to high technology fields such as flat panel displays, nuclear waste disposal, and biomedicine. The book also includes: A thorough introduction to the fundamentals of atomistic simulations, including classical, ab initio, Reverse Monte Carlo simulation and topological constraint theory methods Important ingredients for simulations such as interatomic potential development, structural analysis methods, and property calculations are covered Comprehensive explorations of the applications of atomistic simulations in glass research, including the history of atomistic simulations of glasses Practical discussions of rare earth and transition metal-containing glasses, as well as halide and oxyhalide glasses In-depth examinations of glass surfaces and silicate glass-water interactions Perfect for glass, ceramic, and materials scientists and engineers, as well as physical, inorganic, and computational chemists, Atomistic Simulations of Glasses: Fundamentals and Applications is also an ideal resource for condensed matter and solid-state physicists, mechanical and civil engineers, and those working with bioactive glasses. Graduate students, postdocs, senior undergraduate students, and others who intend to enter the field of simulations of glasses would also find the book highly valuable.

Download or read book Atomistic simulations of Silicate Glasses written by Seung Ho Hahn and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicate-based glasses are one of the most versatile materials in terms of technological perspective with a wide range of industrial applications. In most cases, glass products are exposed to various aqueous environments (either humid air or liquid water) and subject to physical contact with foreign objects, which leads to deterioration of chemical and mechanical properties of glass surfaces. Therefore, understanding their interactions with adsorbed interfacial water molecules is critical as it can provide physical insights needed for rational design of more durable glasses. Experimental characterization approaches have been applied to tackle difficult problems associated with the complex nature of glass surfaces but they are often limited by the time-scale resolution. As a result, they have failed to offer important structural characteristics and chemical reaction mechanisms under dynamic processes happening at the glass surface. To complement the challenges that experimental endeavors are encountering, this dissertation aims to provide a comprehensive understanding of water interactions of silicate glass surfaces using atomistic-scale simulations techniques. In particular, ReaxFF reactive force field-based molecular dynamics (MD) simulations are employed to study two distinct surface phenomena, i) surface water reaction and ii) surface mechanochemical wear process. These studies represent the surface damage process of silicate glass in the absence and presence of mechanical actions, respectively. The first part of this dissertation describes the water interactions of a silicate glass with readily leachable alkali (sodium) ions. In this study, highly complex surface chemistry, including proton/water exchange with the sodium ions, formation of relatively long-living sodium-hydroxide ionic complexes at the glass surface and eventual dissolution of those ion pairs into the water phase are described. Also, surface mapping of water binding energy to the glass surface is evaluated at different stages of the glass-water reaction, which would be relevant to assess the chemical durability of the glass materials based on the glass network topology. After the transport behavior and glass-water reaction mechanism at the surface has been identified, the mechanochemical wear process of sodium silicate glass rubbed with amorphous silica in the absence and presence of interfacial water molecules is covered in the second part of this dissertation. The effect of water molecules on the shear-induced chemical reaction at the sliding interface was investigated and the dependence of wear on the number of interfacial water molecules in ReaxFF-MD simulations was found to be qualitatively in reasonable agreement with the experimental data. The large-scale atomistic simulation approaches with ReaxFF reactive force field presented in this dissertation alleviates the limitations of DFT calculations and experiments, providing new and meaningful insights on the chemical dynamics associated within the glass-water interface.

Download or read book Encyclopedia of Glass Science Technology History and Culture Two Volume Set written by Pascal Richet and published by John Wiley & Sons. This book was released on 2021-02-05 with total page 1568 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Encyclopedia begins with an introduction summarizing itsscope and content. Glassmaking; Structure of Glass, GlassPhysics,Transport Properties, Chemistry of Glass, Glass and Light,Inorganic Glass Families, Organic Glasses, Glass and theEnvironment, Historical and Economical Aspect of Glassmaking,History of Glass, Glass and Art, and outlinepossible newdevelopments and uses as presented by the best known people in thefield (C.A. Angell, for example). Sections and chapters arearranged in a logical order to ensure overall consistency and avoiduseless repetitions. All sections are introduced by a briefintroduction and attractive illustration. Newly investigatedtopics will be addresses, with the goal of ensuring that thisEncyclopedia remains a reference work for years to come.

Download or read book Atomistic Simulation of Materials written by David J. Srolovitz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains proceedings of an international symposium on Atomistic th Simulation of Materials: Beyond Pair Potentials which was held in Chicago from the 25 th to 30 of September 1988, in conjunction with the ASM World Materials Congress. This symposium was financially supported by the Energy Conversion and Utilization Technology Program of the U. S Department of Energy and by the Air Force Office of Scientific Research. A total of fifty four talks were presented of which twenty one were invited. Atomistic simulations are now common in materials research. Such simulations are currently used to determine the structural and thermodynamic properties of crystalline solids, glasses and liquids. They are of particular importance in studies of crystal defects, interfaces and surfaces since their structures and behavior playa dominant role in most materials properties. The utility of atomistic simulations lies in their ability to provide information on those length scales where continuum theory breaks down and instead complex many body problems have to be solved to understand atomic level structures and processes.

Download or read book Atomistic Simulations of Borosilicate Glassess written by Kuo Hao Lee and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been challenging to understand the cracking behavior of oxide glasses under sharp contact due to the complicated stress state in the samples and compositional dependence of the mechanical behavior of glasses. Molecular dynamics (MD) is a powerful technique to study materials structure and properties. By taking advantage of its capability of providing the time-dependent trajectories of all atoms in the system, the in-situ observation of mechanical deformation can be achieved. In this research, we used MD simulations to study the mechanical response of two commercial multi-component borosilicate glasses, Borofloat®33 (Boro33) and N-BK7® (N-BK7), under different loading conditions to obtain a more complete picture of the deformation mechanism of the indented glass from the perspective of atomic scale. This dissertation can be divided into five parts. In the first part, the performances of two sets of classical interatomic potentials for borosilicate glasses were evaluated in terms of structural and elastic properties for the two glass compositions. The results were also compared with available experimental data. It was found that the potential by Wang et al. [M. Wang, N.M. Anoop Krishnan, B. Wang, M.M. Smedskjaer, J.C. Mauro, and M. Bauchy, J. Non. Cryst. Solids, 498 294--304 (2018)] provides a closer N4 value for Boro33 but underpredicts the N4 value for N-BK7. In contrast, the N4 value of N-BK7 using the potential of Deng and Du [L. Deng and J. Du, J. Am. Ceram. Soc., 102 [5] 2482--2505 (2019)] agrees well with the experimental data, but that of Boro33 is overpredicted. Our result also indicates that Wang's potential gives a better prediction in the short-range structure, while Du's potential provides a closer medium-range structure compared with the experimental data. Neither set of potentials is able to provide accurate predictions of elastic moduli. Wang's potential predicts lower elastic modulus due to the underpredicted N4 value, whereas Du's potential yields higher elastic modulus compared with the experimental values, resulting from its overpredicted N4 value. The second part presents the results from cold compression-decompression MD simulations of the borosilicate glasses. Our results suggest that the densification of these two borosilicate glasses involves different types of structural changes. The fraction of permanent densification can be correlated to the change in intermediate-range structure. By performing Voronoi analysis, the contributions to densification from different cation types in these two multicomponent borosilicate glasses were qualified. It was found that 3-coordinated cations facilitate the densification process, and higher-coordinated cations are relatively stable and can even show a slight expansion in their Voronoi volume. The third part describes the shear behaviors of the borosilicate glasses under different pressures. It was found that the addition of alkali ions lowers the yield stress and changes the pressure dependence of shear modulus. Moreover, shear-induced densification was observed in both glasses. The results show that the decreases of the oxygen-centered bond angle and the coordination number change of B are responsible for the density changes at low pressures, and the increase of 5-coordinated Si is the dominant mechanism for densification at high pressures. The atomic shear stress was calculated the results suggest that B is able to relax mechanical stress more easily under pressurized shear compared to other element types. By analyzing the nonaffine displacement of atoms, it was found that N-BK7 exhibits more localized plastic deformation compared to Boro33 at low pressures and the local rearrangements in both glasses become more homogeneous with increasing pressure. The mean squared nonaffine displacement curves show that alkali ions have the highest mobility induced by shear compared to the network formers and B is more mobile than Si for both glasses. It was also observed that plastic deformation tends to take place around boron atoms for Boro33, whereas it occurs in the alkali-rich regions for N-BK7, indicating that these two glasses have different atomic-scale deformation mechanisms. In the fourth part, the plasticity of the two glasses under tension was investigated by implementing a uniaxial tension test using MD simulations. A bond-switching mechanism is found to be responsible for the plastic response of both glasses and is governed by the increasing rate of non-bridging oxygen (NBO) production during the uniaxial tension. It was found that the amount of B4OSi4 linkages in the glass governs the stress drop after yielding, due to its higher tendency to create NBOs compared to Si4OSi4. Also, the initial existence of NBOs weakens the critical stress for breaking the B4-O bond in B4OSi4, which in turn lowers the yield strength of the glass. The last part describes the effects of pressure on elastic properties, surface energy, and fracture toughness (K_IC) of the borosilicate glasses. It was found that the impact on K_IC is mainly dominated by the change of Young's modulus under pressure, which is proportional to the relative change in density. Between the two glasses under investigation, K_IC can be improved more effectively by the hot-compression process for Boro33, due to its higher concentration of 3-coordinated boron (B3), which facilitates densification via B3 to B4 conversion under compression.

Download or read book Atomistic Simulations to Study Metallic Glasses a Microscopic Investigation of Local Structural Excitations written by Soumya Swayamjyoti and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atomistic Simulations of Flash Memory Materials Based on Chalcogenide Glasses written by Bin Cai and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomistic Simulations of Flash Memory Materials Based on Chalcogenide Glasses.

Download or read book Atomistic Simulation of Materials written by David J. Srolovitz and published by Springer. This book was released on 2012-03-19 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains proceedings of an international symposium on Atomistic th Simulation of Materials: Beyond Pair Potentials which was held in Chicago from the 25 th to 30 of September 1988, in conjunction with the ASM World Materials Congress. This symposium was financially supported by the Energy Conversion and Utilization Technology Program of the U. S Department of Energy and by the Air Force Office of Scientific Research. A total of fifty four talks were presented of which twenty one were invited. Atomistic simulations are now common in materials research. Such simulations are currently used to determine the structural and thermodynamic properties of crystalline solids, glasses and liquids. They are of particular importance in studies of crystal defects, interfaces and surfaces since their structures and behavior playa dominant role in most materials properties. The utility of atomistic simulations lies in their ability to provide information on those length scales where continuum theory breaks down and instead complex many body problems have to be solved to understand atomic level structures and processes.

Download or read book Understanding Structure Thermodynamics and Dynamics of Silica Liquids and Glasses Using Atomistic Simulations and Machine Learning written by Zheng Yu and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glass materials are found all around us, but fundamental questions about the nature of their amorphous structures and formation processes remain unsolved after decades of research. In this dissertation, silica, an archetype glass former, is taken as an example glass for investigations into glass structures, thermodynamics, dynamics, two-level systems (TLS), and atomic interactions based on molecular dynamics simulations and machine learning methods. Specifically, we investigate the structure-thermodynamic stability relationship using a library of silica inherent structures generated from melt-quench and replica exchange molecular dynamics simulations. Based on machine learning, we find that short-range and medium-range features play very different roles on the glass stability across the liquid and glass regions. We then revisit an interesting dynamical transition in silica liquid, the fragile-to-strong transition (FTS), from the perspective of microscopic dynamics. By machine learning to classify atomic rearrangements, the FTS is found to originate from the two types of energy barriers in silica, representing a fast and a slow microscopic dynamics channel. The fast channel controlled by the short-range defects closes rapidly with decreasing temperature, causing the fragility crossover. A similar approach is also applied to investigate TLS. We predict TLS densities in a large number of inherent structures with a variety of glass stability using machine learning and verify them using molecular dynamics simulations. We find a decrease in the TLS density with the fictive temperature, which can be described by a quadratic function as suggested by the random first-order transition theory. Lastly, we introduce a linear machine learning force matching approach that can directly extract pair atomic interactions from ab initio calculations in amorphous materials. This approach is applied to silica to understand the atomic interactions within its structure and develop a new classical force field. Through the comprehensive fundamental investigations on the nature of silica glass and liquid, I hope the understandings and methods presented in this dissertation can be transferred to study other glass-forming systems.

Download or read book Glasses and Glass Ceramics written by K. Annapurna and published by Springer Nature. This book was released on 2022-11-29 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents various useful processing techniques and applications of glasses and glass-ceramics. It covers various topics such as introduction to glass, its properties, thermodynamics of glass, heat transfer in glass melts, color in glass and advanced characterization techniques to analyze structure of glasses and glass-ceramics along with functional glasses and glass ceramics for advanced applications. This book will be a useful reference for students, researchers, scientists and technologists working in the field of materials science, especially glass.

Download or read book Bulk Metallic Glasses written by Michael Miller and published by Springer Science & Business Media. This book was released on 2007-09-26 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bulk metallic glasses are a new emerging field of materials with many desirable and unique properties. These amorphous materials have many diverse applications from structural applications to biomedical implants. This book provides a complete overview of bulk metallic glasses. It covers the principles of alloy design, glass formation, processing, atomistic modeling, computer simulations, mechanical properties and microstructures.

Download or read book Heterogeneities in Metallic Glasses Atomistic Computer Simulations on the Structure and Mechanical Properties of Copper zirconium Alloys and Composites written by Tobias Brink and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Dynamics Simulations of Disordered Materials written by Carlo Massobrio and published by Springer. This book was released on 2015-04-22 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a unique reference work in the area of atomic-scale simulation of glasses. For the first time, a highly selected panel of about 20 researchers provides, in a single book, their views, methodologies and applications on the use of molecular dynamics as a tool to describe glassy materials. The book covers a wide range of systems covering "traditional" network glasses, such as chalcogenides and oxides, as well as glasses for applications in the area of phase change materials. The novelty of this work is the interplay between molecular dynamics methods (both at the classical and first-principles level) and the structure of materials for which, quite often, direct experimental structural information is rather scarce or absent. The book features specific examples of how quite subtle features of the structure of glasses can be unraveled by relying on the predictive power of molecular dynamics, used in connection with a realistic description of forces.

Download or read book Atomistic Modelling and Prediction of Glass Forming Ability in Bulk Metallic Glasses written by Sina Sedighi and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Glass Properties written by Narottam P. Bansal and published by Elsevier. This book was released on 2013-10-22 with total page 691 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is a compilation of data on the properties of glasses. The authors have critically examined and correlated the most reliable data on the properties of multicomponent commercial silicate glasses, vitreous silica, and binary and ternary laboratory glasses. Thermodynamic, thermal, mechanical, electrical, and transport properties are covered. Measurement methods and appropriate theories are also discussed.

Download or read book Cooling Rate and Stress Relaxation in Silica Melts and Glasses Via Microsecond Molecular Dyanmics written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have conducted extremely long molecular dynamics simulations of glasses to microsecond times, which close the gap between experimental and atomistic simulation time scales by two to three orders of magnitude. The static, thermal, and structural properties of silica glass are reported for glass cooling rates down to 5×109 K/s and viscoelastic response in silica melts and glasses are studied over nine decades of time. We finally present results from relaxation of hydrostatic compressive stress in silica and show that time-temperature superposition holds in these systems for temperatures from 3500 to 1000 K.

Download or read book Atomistic Contribution to the Understanding of Metallic and Silica Glasses written by Pawel Koziatek and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amorphous materials are ubiquitous in everyday life. They comprise "hard" and"soft" glasses. Hard amorphous systems are usually seen as structure materials, with properties and use comparable to those of crystalline solids. Soft glasses are usually seen as complex fluids, described in terms of their rheological properties with the corresponding practical applications (concrete, paints, drilling mud, cosmetic gels, creams or foams, etc). Amorphous materials can either present a solid-like behaviour or flow depending on their mechanical load: all are yield-stress fluids. Their usage limits are often defined by the occurrence of shear-banding, an extreme form of localization seen in molecular glasses as well as in granular materials. There is now considerable evidence that they are consequences of the existence of a disordered structure at the level of the elementary constituents (atoms, particles,...). Studies of plasticity in amorphous solids, are still hampered by the lack of any identifiable defect responsible for the plastic response. It is now acknowledged that plasticity is the net result of local rearrangements, or "shear transformations", involving small clusters of (say a few tens of) particles. These rearrangements are thermally--activated and are ubiquitous processes in the structural relaxation and deformation of glasses at low temperatures. Unfortunately, they take place over timescales long compared to those accessible to direct Molecular Dynamics simulations. Some extremely promising new tools, however, are opening the route towards accelerated algorithms for the simulation of thermal systems. They are based on numerical methods developed over these last two decades to determine thermally activated transitions in atomic systems. Of particular interest here is the Activation-Relaxation Technique (ART), an eigenvector-following method that allows the identification of activated states and paths in the potential energy landscape of atomic systems. In this study, we will show that although an exhaustive search for saddle points in case of disordered solids is unfeasible (because of the exponential number of activated states), ART can identify enough saddles to build statistically relevant samples, from which stationary distributions can be computed. The purpose of this strictly numerical thesis was the prediction of thermally activated kinetics in glasses such as those encountered experimentally. The nature of such miscroscopic events occuring in disordered systems was studied both under mechanical stress and in ageing conditions. We investigate two quantities that describe thermally-activated events within the harmonic approximation of the transition state theory, i.e. activation energy and attempt frequency.Since in the definition of an attempt frequency the curvature of the initial minimum and the saddle point are present, we wanted to see if there was a relation between attempt frequencies and activation energies of a given event in two types of systems: metallic glasses and silica glasses. Such correlation had been observed before for a wide range of phenomena and is referred to as the Meyer-Neldel compensation rule. We also attempt to answer if the simple BKS potential without Ewald summation is able to reproduce polyamorphism observed in silica glasses subject to hydrostatic compression and characterized mainly in terms of coordination numbers. Apart from thermally activated processes, the structural analyses of metallic and silica glasses were performed. The short and medium range orders were characterized using two methods: Voronoi tesselations for metallic glasses, providing us information about near neighbor conformations, and in case of silica, statistics of ring distributions.