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Book Structure Property Relations of Mixed Alkali and Ion Exchange Silicate Glasses

Download or read book Structure Property Relations of Mixed Alkali and Ion Exchange Silicate Glasses written by Courtney Marie Calahoo and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improvement of the mechanical properties of glass was undertaken by furthering understanding of the fundamental relationships between composition, structure and mechanical response. Glasses which were known to already have desirable mechanical properties were made and analysed in order to establish correlations between different properties. Ion exchange (IE), where a smaller ion is replaced by a larger ion without subsequent structural relaxation, causes surface compressive stresses which increase strength and scratch resistance significantly. Micro-Raman spectroscopy was employed to directly measure the volumetric negative strain (contraction) and compressive stress as a function of IE processing temperature by observing changes in Raman peaks correlated with Si-O bond lengths and Si-O-Si bond angles. From the Raman data, the strain of the glass network and consequent stress was calculated relative to several reference states. The reference state of relaxed, fully exchanged glass produced results which matched the complex experimental behaviour. The mechanical response of the IE layer was probed using nano-indentation. Stiffness and hardness were measured as a function of distance from the surface and IE temperature. Additionally, elastic recovery and resistance to plastic deformation were determined. Low IE temperatures (which the Raman results indicated contained the most compressive stress) were observed to improve mechanical properties more than higher IE temperatures, likely due to increased thermal relaxation. The mixed-modifier effect (MME), a deviation from additivity when two or more different types of modifying cations are combined, is known to exist in in static, dynamic and mechanical properties. Yet, the underlying mechanism of the MME is poorly understood, thus, a comprehensive study of several mixed-modifier glass series was undertaken to better elucidate the complex relationships between these three categories of properties. The most significant predictor of the MME was the valence(s) of the mixed cations. Furthermore, the MME in conductivity, packing fraction, bulk modulus, hardness and fracture toughness was related to relative cationic field strength and ionic radii. The MME in shear modulus, Young's modulus and Poisson's ratio was related to structural connectivity rather than the properties of the modifier cations.

Book Field Strength Effect on the Elastoplastic and Mechanical Properties of Single Modifier Aluminoborosilicate Glasses

Download or read book Field Strength Effect on the Elastoplastic and Mechanical Properties of Single Modifier Aluminoborosilicate Glasses written by Aubrey Fry and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theoretical strength of glass far exceeds its measurable strength. The limiting factor is glass's sensitivity to surface flaws, largely due to handling. Silicate glasses are the largest commercially used glass family because they are highly versatile and can be designed with many enhanced properties. Decades worth of patents and scientific literature discuss intrinsic and extrinsic strengthening mechanisms that compensate for glass's sensitivity to surface damage, including thermal tempering, ion exchange, ceramming, lamination, etc. The focus of this dissertation is to explore the impact of modifier field strength on the mechanical response of aluminoborosilicate glasses designed to have intrinsic damage resistance. By exploring the strengthening mechanisms at the atomic level, it is possible to gain a deeper understanding of how the glass composition governs physical properties and its mechanical response. Based on the principle of topological adaptability, aluminoborosilicate (ABS) glasses can be designed with intrinsically high damage resistance if they incorporate three-coordinated boron atoms. Using a careful selection of network modifying ions, they can also be amenable for chemical strengthening. This dissertation provides a comprehensive investigation of the effect of field strength (FS) on intrinsic damage resistance considering three monovalent and three divalent modifiers in ABS glasses. Various aspects of mechanical properties were analyzed as a function of network modifier (NWM) field strength and the magnitude of the applied stress. Results from this work help to (i) reevaluate assumptions regarding glass structure, (ii) improve future mechanical testing procedures, and (iii) gain insights into the cracking behavior and deformation mechanisms in silicate glasses as a function of modifier field strength and applied stress. (1) Atomic Structure: The first major discovery from this work regards the atomic structure of high strain point, mixed former glasses. For the current ABS glasses, the ratio of network formers and the low concentration of modifier oxides, in addition to high processing temperatures, increases the entropic contribution to the glass structure such that the enthalpically driven modifier and network former (NWF) interactions are frustrated. Therefore, in such systems it cannot be assumed that all Al3+ cations will be four-coordinated even if [NWM] >= [Al2O3] (concentrations denoted by square brackets). (2) Hardness and Crack Resistance: The second major discovery from this work addresses the simultaneous increase of both hardness (H) and crack resistance (CR) as a function of modifier field strength. Historically, an increase in H is presumably marked by an increase in rigidity and the probability of crack initiation. This is not the case for the current compositions, which brings the assumption of the inverse relationship between H and CR into question, specifically for glasses that might not be classified as normal. (3) Plasticity: The third discovery of this work involves the nuanced relationship between H, CR, and plasticity. Plasticity (VP) increases with modifier field strength, similar to H and CR. These findings appear counterintuitive since hardness is a measure of resistance to plastic deformation. It is found that a balance of plastic deformation mechanisms, namely, shear flow and densification, allow for an increase in H, CR, and plasticity as a function of field strength. (4) Topological Adaptability: The fourth major finding from this dissertation involves the predominant assumptions regarding topological adaptability. The topological adaptability is mainly attributed to two mechanisms: (i) the reduction in free volume under an applied stress (e.g., a decrease in bond length or angle), and (ii) structural unit conversion under an applied stress (e.g., NWF coordination changes). The first attribute is quantified by a decrease in molar volume (VM) post indentation or compression, and the second attribute is enabled by an initially high concentration of three-coordinated boron ([B3]). It is generally accepted that CR increases as topological adaptability is enhanced. The ABS glasses in this study were designed to take advantage of both mechanisms, while changing the modifier FS. Although this work did not systematically explore the impact of varying VM and [B3] on CR, it did show that CR increased as VM decreased. While this work implies that the topological adaptability can be helped or hindered based on the modifier species, future work needs to be done to systematically monitor changes in VM and CR as a function of varying [B3] in a series of related ABS glasses. (5) Poisson's Ratio: The fifth discovery from this research is that the suggested link between Poisson's ratio and cracking behavior should be reexamined. The elastic modulus increases with field strength but the Poisson's ratio did not trend with any measured property, namely, the VM and CR. Poisson's ratio has been touted as holding the key to understand cracking behavior in oxide glasses, but this is not the case for the current compositions. This misconception is likely due to the large amount of research conducted on normal (e.g., soda-lime silicate) and anomalous (e.g., pure silica) glasses which tend to ignore the intermediate glasses or mixed former glasses. (6) Elastic to Plastic Ratio: The sixth finding of this research has a direct connection to application: the mechanical performance of glass under increasing stress. The elastic-to-plastic deformation ratio (VE/VP) increases as the applied load increases. For the current compositions, a higher load results in a greater elastic response, which may help to explain static vs dynamic fatigue phenomena where a glass appears to be "stronger" when tested at higher strain rates. (7) Fracture Toughness: The seventh major discovery of this work is that the fracture toughness (KIc) of the alkaline earth glasses increases as a function of modifier field strength. Predicting fracture toughness has eluded many researchers both in ceramic and glass sciences. KIc has been related to a variety of material properties, but there is no universal predictor for how a material will perform during a fracture toughness test, especially since property trends are often found to deviate when changing the length scale of the test. From this work, results indicate that the hardness (micro-scale), crack resistance (meso-scale), fracture toughness (meso- to macro-scale), and the elastic moduli (bulk) all increase in ABS glasses with increasing FS, which has not been shown before. Additionally, the material property that had the highest linear correlation with KIc was VE/VP, indicating that a volumetric recovery study may serve as a new micro-scale test that can help predict the fracture toughness performance of ABS glasses. The goal of this dissertation is to explore the impact of glass composition on the elastoplastic response and mechanical performance of six novel single modifier aluminoborosilicate glasses. This work finds that modifier FS has a distinct role influencing mechanical properties and cracking behavior, even at modifier concentrations of around 10 mole percent. By rethinking glass chemistry accounting for these effects, properties such as hardness, crack resistance, elastic modulus, and even fracture toughness can be improved.

Book Tellurite Glasses Handbook

Download or read book Tellurite Glasses Handbook written by Raouf A.H. El-Mallawany and published by CRC Press. This book was released on 2014-10-31 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-crystalline solid tellurite glasses continue to intrigue both academic and industry researchers not only because of their many technical applications, but also because of a fundamental interest in understanding their microscopic mechanisms. Tellurite Glasses Handbook: Physical Properties and Data is the first and only comprehensive sourc

Book Tellurite Glasses Handbook

Download or read book Tellurite Glasses Handbook written by Raouf A.H. El-Mallawany and published by CRC Press. This book was released on 2016-04-19 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tellurite Glasses Handbook: Physical Properties and Data, Second Edition covers the current dominant physical properties of this prototype glass system. Focusing on thermal, elastic, acoustic, electrical, and optical properties, this second edition incorporates the latest scientific data and up-to-date applications of tellurite glass. New Topics in

Book Technological Advances in Tellurite Glasses

Download or read book Technological Advances in Tellurite Glasses written by V.A.G. Rivera and published by Springer. This book was released on 2017-03-30 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the first to provide a comprehensive introduction to the synthesis, optical properties, and photonics applications of tellurite glasses. The book begins with an overview of tellurite glasses, followed by expert chapters on synthesis, properties, and state-of-the-art applications ranging from laser glass, optical fibers, and optical communications through color tuning, plasmonics, supercontinuum generation, and other photonic devices. The book provides in-depth information on the the structural, linear, and non-linear optical properties of tellurite glasses and their implications for device development. Real-world examples give the reader valuable insight into the applications of tellurite glass. A detailed discussion of glass production methods, including raw materials and melting and refining oxide- and fluoro-tellurite glasses, is also included. The book features an extensive reference list for further reading. This highly readable and didactic text draws on chemical composition, glass science, quantum mechanics, and electrodynamics. It is suitable for both advanced undergraduate and graduate students as well as practicing researchers.

Book The Structure and Mechanical Properties of Inorganic Glasses

Download or read book The Structure and Mechanical Properties of Inorganic Glasses written by Georgiĭ Mikhaĭlovich Bartenev and published by . This book was released on 1970 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Mechanical Properties of Water Soluble Silicate Glasses

Download or read book The Mechanical Properties of Water Soluble Silicate Glasses written by Charles Wesley Jennings and published by . This book was released on 1973 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Handbook of Glass Properties

Download or read book Handbook of Glass Properties written by Narottam P. Bansal and published by Academic Press. This book was released on 1986-05-28 with total page 700 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.

Book Mechanical and Electrical Properties of Thick Film Silicate Glasses on Stainless Steel

Download or read book Mechanical and Electrical Properties of Thick Film Silicate Glasses on Stainless Steel written by Christopher D. Blair and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The measurement of the surface mechanical properties of silicate glasses using a stress wave emission detection technique

Download or read book The measurement of the surface mechanical properties of silicate glasses using a stress wave emission detection technique written by William Edward Swindlehurst and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Mixed Modifier Effect in Aluminosilicate Glasses

Download or read book Mixed Modifier Effect in Aluminosilicate Glasses written by Yinan Lin and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this PhD study are to gain insights into mass transport-related properties, e.g., glass transition temperature, Vickers hardness, and activation energy of dynamic dissolution, of mixed modifier aluminosilicate glasses and gain a coherent understanding of the mechanism of mass transfer. The primary objective is to propose and apply an experimental framework that can be capable of predicting these properties for multicomponent glasses containing mixtures of network modifiers. Pairwise and ternary interactions are examined experimentally to understand the mixed modifier effect (MME) in a series of ternary modifier containing (Na2O·K2O·CaO) aluminosilicate glasses. The pairwise model follows from the work of LaCourse [LaCourse WC. A defect model for the mixed alkali effect. J Non-Cryst Solids. 1987;95-96:905--912.]. By keeping the glass network former concentration constant and adjusting the molar ratios of the three network modifiers, the glass transition temperature (Tg), Vickers hardness (Hv) and activation energy (Ea) for aqueous dissolution of each modifier cation are investigated. We examine whether the pairwise interaction model is sufficient, or if ternary interactions also need to be included to predict the MME in these more complicated glass systems. This work reveals that the pairwise model can be used to predict the mixed modifier effect for Tg in complex multiple-modifier glass system by solely using a combination of binary systems involving the two-body interaction factors. However, ternary mixed-modifier interactions are present in other properties such as Hv and Ea. The outcomes suggest pathways that could be used to improve the chemical durability of aluminosilicate glasses by compositional alternations that enhance network rigidity.

Book Static and Dynamic Fatigue of Silicate Glasses

Download or read book Static and Dynamic Fatigue of Silicate Glasses written by Charles L. Sherburne and published by . This book was released on 1971 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: