Dissertations / Theses on the topic 'Glass properties'

We use Monte Carlo simulations in order to investigate the density of states and the two-time density autocorrelation function for the two- and three-dimensional Coulomb glass as well as the Bose glass phase of flux lines in type-II superconductors. We find a very fast forming gap in the density of states and explore the dependence of temperature and filling fraction. By studying two scaling methods, we find that the nonequilibrium relaxation properties can be described sufficiently by a full-aging scaling analysis. The scaling exponents depend on both temperature and filling fraction, and are thus non-universal. We look at the trends of these exponents and found that as either the temperature decreases or the filling fraction deviates more from half-filling, the exponents reflect slower relaxation kinetics. With two separate interaction potentials, a comparison of relaxation rates and the gap in the density of states is made.
Ph. D.

Thesis (M.S.)--University of Missouri--Rolla, 2007.
Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 25, 2008) Includes bibliographical references (p. 52-54).

The effects of in situ Ti0₂ whisker reinforcement on mechanical and thermal properties of glass-ceramics in the Li₂O-Al₂0₃-P₂0₆-Si0₂ system were investigated. When Ti0₂ whiskers, having an average aspect ratio of 28, are precipitated from the glass-ceramic matrix, (Li_0.4,Ca_0.05)AI(Si_{0.75>/sub>,P0.5)04.5, flexural strength is improved from 72 to 134 MPa. Fracture toughness, KIc, is increased from the 1.1 to 1.6 MPa·m^1/2 due to crack deflection by the Ti0₂ whiskers. In situ Ti0₂ whisker-reinforced glass-ceramic exhibits rising fracture resistance, KR, with increasing crack extension. The fracture resistance, KR, is increased from 1.89 to 2.5 MPa·m^1/2 over the crack extension range range of 40 to 200 μm. The composite shows a narrow failure strength distribution compared to the glass-ceramic without Ti0₂ whisker precipitation. The coefficient of thermal expansion (CTE) changes from -2.8x10⁻⁷/"C to -1.7xl0⁻⁷/°C due to the precipitation of Ti0₂ phase which has a positive CTE (7.3xl0⁻⁶/°C). With the matrix composition, (Li0.41,Mg0.035)AI(Si00.48},P_O.52)O₄, a three-fold increase in flexural strength was observed with a Ti0₂ content of 12 wt%. CTE value of the composite increases linearly from a negative to a positive value with increasing Ti0₂ content up to 12 wt%. The in situ composite containing 8-10 wt% Ti0₂ exhibits near zero CTE values up to l000°C.
Ph. D.

Woven glass composites have been used for many years in commercial applications due to their light weight, competitive price and good engineering properties. Absorption of energy by laminated composite material results in damage in various forms, the most common of which is delamination. Inter-laminar fracture causes the layers of composite to separate, resulting in a reduction in stiffness and strength of the composite structure, matrix cracking and in some cases fibre breakage takes place. The aim of this project was to improve the inter-laminar bond strength between woven glass fabric and resin. Air jet texturing was selected to provide a small amount of bulk to the glass yarn. The purpose was to provide more surface contact between the fibres and resin and also to increase the adhesion between the neighbouring layers. These were expected to enhance the resistance to delamination in the woven glass composites.Glass yarns were textured by a Stähle air jet texturing machine. Core-and-effect yarn was produced instead of a simple air textured yarn. Hand loom and vacuum bagging techniques were used for making the fabric and composite panels from both textured and non-textured yarns. Density and fibre volume content were established for physical characterisation. Breaking strength (tenacity) of the yarns and tensile, flexure, inter-laminar shear strength (ILSS) and fracture toughness (mode 1) properties of the composites were determined. Projection microscopy and SEM imaging techniques were used to assess the fractured surfaces of the composite specimens. The yarn tenacity and the tensile properties of the composites were significantly reduced after the texturing process, whereas flexure properties were unchanged. However, significant improvement was observed in the ILSS and fracture toughness of the composites after the texturing process. It was also observed that the composites made from the fabrics with textured yarns in only the weft direction are the most advantageous as they maintained the tensile and flexure properties but have significantly higher inter-laminar shear strength.

Apatite containing bioceramic materials are considered to be potentially useful for replacement or repair of natural bone. In the present study, the aim was to produce a new composite bioceramic containing crystalline apatite and wollastonite phases with a bimodal grain size distribution. The manufacturing scheme was based on the liquid phase sintering process in which the compacts pressed from powders of apatite (HAP or Si­
HAP) and pseudowollastonite was sintered in the presence of a liquid phase. Three distinct fluxing agents, magnesium flux (MCAS), sodium feldspar and sodium frit (NCAS), were prepared to act as additives for generating the liquid phase during sintering. Among those, the use of sodium frit resulted in the expected bimodal microstructural assembly. During the sintering studies, it was discovered that the apatite component of the ceramic was prone to compositional modifications by reaction with the liquid phase. This interaction resulted in a formation of siliconized HAP which crystallized in the form of rod-like grains. Meanwhile wollastonite grains tended to exhibit faceted equiaxed morphology and bonded to rod-like apatite grains with the help of a glassy phase. The results showed significant enhancement in the mechanical properties of apatite-wollastonite composites compared to phase pure hydroxyapatite. For example, the sample with 47.5 wt% Si-HAP2 + 47.5 wt% W + 5 wt% NCASfrit had the highest value of flexural strength, 83.6 MPa, which was almost twice that of hydroxyapatite, 46.3 MPa. The results for other properties such as compressive strength, hardness and fracture toughness also demonstrated the benefit of apatite-wollastonite composite approach.

This research provides a comprehensive investigation in understanding the effect of the addition of graphene nano-platelets (GNP) on the mechanical, tribological and biological properties of glass/ceramic composites. We investigated two kinds of materials namely amorphous matrices like glasses (silica, bioglass) and polycrystalline matrices like ceramics (alumina). The idea was to understand the effect of GNP on these matrices as GNP was expected to behave differently in these composites. Bioglass (BG) was also chosen as a matrix material to prepare BG-GNP composites. GNP can improve the electrical conductivity of BG which can be used further for bone tissue engineering applications. The effect of GNP on both electrical conductivity and bio-activity of BG-GNP composites was investigated in detail. There were three main problems for fabricating these novel nano-composites: 1) Production of good quality graphene; 2) Homogeneous dispersion of graphene in a glass/ceramic matrix and; 3) Retention of the graphitic structure during high temperature processing. The first problem was solved by synthesising GNP using liquid phase exfoliation method instead of using a commercially available GNP. The prepared GNP were ~1 μm in length with a thickness of 3-4 layers confirmed using transmission electron microscopy. In order to solve the second problem various processing techniques were used including powder and colloidal processing routes along with different solvents. Processing parameters were optimised to fabricate glass/ceramic-GNP composite powders. Finally in order to avoid thermal degradation of the GNP during high temperature processing composites were sintered using spark plasma sintering (SPS) technique. Fully dense composites were obtained without damaging GNP during the sintering process also confirmed via Raman spectroscopy. Finally the prepared composites were characterised for mechanical, tribological and biological applications. Interestingly fracture toughness and wear resistance of the silica nano-composites increased with increasing concentration of GNP in the glass matrix. There was an improvement of ~45% in the fracture toughness and ~550% in the wear resistance of silica-GNP composites with the addition of 5 vol% GNP. GNP was found to be aligned in a direction perpendicular to the applied force in SPS. In contrast to amorphous materials fracture toughness and scratch resistance of alumina-GNP composites increased only for small loading of GNP and properties of the composites decreased after a critical concentration. There was an improvement of ~40% in the fracture toughness with the addition of only 0.5 vol% GNP in the alumina matrix while the scratch resistance of the composite increased by ~10% in the micro-ductile region. Electrical conductivity of the BG-GNP composite was increased by ~9 orders of magnitude compared to pure BG. In vitro bioactivity tests performed on BG-GNP composites confirmed that the addition of GNP to BG matrix also improved the bioactivity of the nano-composites confirmed using XRD analysis. Future work should focus on understanding electrical and thermal properties of these novel nano-composites.

Dental restorative cements are placed in a harsh oral environment where they are subjected to thermal shock, chemical degradation, and repeating masticatory force. The ideal restorative dental cements should have superior mechanical properties, chemical stability, aesthetic, good handling properties, biocompatibility, antibacterial properties, and preferably bioactivity. This thesis presents research on dental restorative cements with enhanced properties. The overall aim was to increase the bioactivity and antibacterial properties of dental restorative cements without affecting their other properties. The effect from adding calcium silicate to glass ionomer cement (GIC) was investigated. The results showed that calcium silicate could increase the bioactivity and reduce the cytotoxicity of conventional glass ionomer cement without compromising its setting and mechanical properties. Hydroxyapatite (HA) with a high aspect ratio and thin nacreous-layered monetite sheets were also synthesized. Nano HA particles with an aspect ratio of 50 can be synthesized by both precipitation and hydrothermal methods. The aspect ratio was controlled via the pH of reaction medium. Thin nacreous-layered monetite sheets were synthesized through a self-assembly process in the presence of an amine based cationic quaternary surfactant. Temperature, pH, and presence of surfactant played essential roles in forming the nacreous-layered monetite sheets. Then the effect from adding silver doped HA and monetite particles was investigated. The results showed that the antibacterial properties of GIC could be increased by incorporating silver doped HA and monetite particles. Further examination showed that the pH change, F- ion release, and concentration of released Ag+ ions were not responsible for the improved antibacterial properties. The quasi-static strengths and compressive fatigue limits of four types of the most commonly used dental restorations were evaluated. In our study, resin modified GIC and resin-based composite showed superior static compressive strength and fatigue limits compared to conventional GIC. The static compressive strength of dental cements increased with the aging time. However, aging had no effect on the compressive fatigue limit of resin modified GIC and resin-based composite. The compressive fatigue limit of conventional GIC even showed a drastic decrease after aging.

Lack of crystalline order and microstructural features such as grain/grain-boundary in metallic glasses results in a suite of remarkable attributes including very high strength, close to theoretical elasticity, high corrosion and wear resistance, and soft magnetic properties. By altering the morphology and tuning of composition, MGs may be transformed into high-performance catalytic materials. In this study, the catalytic properties of metallic glass powders were demonstrated in dissociating toxic organic chemicals such as AZO dye. BMG powders showed superior performance compared to state of the art crystalline iron because of their high catalytic activity, durability, and reusability. To enhance the catalytic properties, high energy mechanical milling was performed to increase the surface area and defect density. Iron-based bulk metallic glass (BMG) of composition Fe48Cr15Mo14Y2C15B6 was used because of its low cost and ability to make large surface area by high energy ball milling. AZO dye was degraded in less than 20 minutes for the 9 hours milled Fe-BMG. However, subsequent increase in ball milling time resulted in devitrification and loss of catalytic activity as measured using UV-Visible spectroscopy. Aluminum-based bulk metallic glass (Al-BMG) powder of composition Al82Fe3Ni8Y7 was synthesized by arc-melting the constituent elements followed by gas-atomization. The particle size and morphology were similar to Fe-BMG with a fully amorphous structure. A small percentage of transition metal constituents (Fe and Ni) in a mostly aluminum alloy showed high catalytic activity, with no toxic by-products and no change in surface characteristics. Al-alloy particles, being light-weight, were easily dispersed in aqueous medium and accelerated the redox reactions. The mechanism of dye dissociation was studied using Raman and Infrared (IR) spectroscopy. Breaking of -C-H- and - C-N- bonds of AZO dye was found to be the primary mechanism. Mechanical behavior of individual BMG particles was evaluated by in situ pico-indentation in a scanning electron microscope (SEM) to understand the fracture mechanisms. Catastrophic shear banding was found to be the primary fracture mode, which supported the observation of flake formation during high energy ball milling.

Робота публікується згідно наказу Ректора НАУ від 27.05.2021 р. №311/од "Про розміщення кваліфікаційних робіт здобувачів вищої освіти в репозиторії університету". Керівник роботи: доцент, к.т.н. Закієв Вадим Ісламович
This master thesis is dedicated to the сomparative study of glass strength using scratch test technique. The methods of investigation are scratch tests, nanoindentation and calculation methods for results analysis.
Ця магістерська робота присвячена порівняльному вивченню міцності скла за допомогою методики випробування дряпанням. Методами дослідження є скретч-тести, наноіндентування та розрахункові методи аналізу результатів.

In the course of this PhD thesis metastable Cu50Zr50-xTix (0≤ x ≤ 10) and (Cu0.5Zr0.5)100-xAlx (5 ≤ x ≤ 8) alloys were prepared and characterised in terms of phase formation, thermal behaviour, crystallisation kinetics and most importantly in terms of mechanical properties. The addition of Al clearly enhances the glass-forming ability although it does not affect the phase formation. This means that the Cu-Zr-Al system follows the characteristics of the binary Cu-Zr phase diagram, at least for Al additions up to 8 at.%. Conversely, the presence of at least 6 at.% Ti changes the crystallisation sequence of Cu50Zr50-xTix metallic glasses and a metastable C15 CuZrTi Laves phase (Fd-3m) precipitates prior to the equilibrium phases, Cu10Zr7 and CuZr2. A structurally related phase, i.e. the “big cube” phase (Cu4(Zr,Ti)2O, Fd-3m), crystallises in a first step when a significant amount of oxygen, on the order of several thousands of mass-ppm (parts per million), is added. Both phases, the C15 Laves as well as the big cube phase, contain pronounced icosahedral coordination and their formation might be related to an icosahedral-like short-range order of the as-cast glass. However, when the metallic glasses obey the phase formation as established in the binary Cu-Zr phase diagram, the short-range order seems to more closely resemble the coordination of the high-temperature equilibrium phase, B2 CuZr. During the tensile deformation of (Cu0.5Zr0.5)100-xAlx bulk metallic glasses where B2 CuZr nanocrystals precipitate polymorphically in the bulk and some of them undergo twinning, which is due to the shape memory effect inherent in B2 CuZr. Qualitatively, this unique deformation process can be understood in the framework of the potential energy landscape (PEL) model. The shear stress, applied by mechanically loading the material, softens the shear modulus, thus biasing structural rearrangements towards the more stable, crystalline state. One major prerequisite in this process is believed to be a B2-like short-range order of the glass in the as-cast state, which could account for the polymorphic precipitation of the B2 nanocrystals at a comparatively small amount of shear. Diffraction experiments using high-energy X-rays suggest that there might be a correlation between the B2 phase and the glass structure on a length-scale less than 4 Å. Additional corroboration for this finding comes from the fact that the interatomic distances of a Cu50Zr47.5Ti2.5 metallic glass are reduced by cold-rolling. Instead of experiencing shear-induced dilation, the atoms become more closely packed, indicating that the metallic glass is driven towards the more densely packed state associated with the more stable, crystalline state. It is noteworthy, that two Cu-Zr intermetallic compounds were identified to be plastically deformable. Cubic B2 CuZr undergoes a deformation-induced martensitic phase transformation to monoclinic B19’and B33 structures, resulting in transformation-induced plasticity (TRIP effect). On the other hand, tetragonal CuZr2 can also be deformed in compression up to a strain of 15%, yet, exhibiting a dislocation-borne deformation mechanism. The shear-induced nanocrystallisation and twinning seem to be competitive phenomena regarding shear band generation and propagation, which is why very few shear offsets, due to shear banding, can be observed at the surface of the bulk metallic glasses tested in quasistatic tension. The average distance between the crystalline precipitates is on the order of the typical shear band thickness (10 - 50 nm) meaning that an efficient interaction between nanocrystals and shear bands becomes feasible. Macroscopically, these microscopic processes reflect as an appreciable plastic strain combined with work hardening. When the same CuZr-based BMGs are tested in tension at room temperature and at high strain rate (10-2 s-1) there seems to be a “strain rate sensitivity”, which could be related to a crossover of the experimental time-scale and the time-scale of the intrinsic deformation processes (nanocrystallisation, twinning, shear band generation and propagation). However, further work is required to investigate the reasons for the varying slope in the elastic regime. As B2 CuZr is the phase, that competes with vitrification, it precipitates in a glassy matrix if the cooling rate is not sufficient to freeze the structure of the liquid completely. The pronounced work hardening and the plasticity of the B2 phase, which are a result of the deformation-induced martensitic transformation, leave their footprints in the stress-strain curves of these bulk metallic glass matrix composites. The behaviour of the yield strength as a function of the crystalline volume fraction can be captured by the rule of mixtures at low crystalline volume fractions and by the load bearing model at high crystalline volume fractions. In between both of these regions there is a transition caused by percolation (impingement) of the B2 crystals. Furthermore, the fracture strain can be modelled as a function of the crystalline volume fraction by a three-microstructural-element body and the results imply that the interface between B2 crystals and glassy matrix determines the plastic strain of the composites. The combination of shape memory crystals and a glassy matrix leads to a material with a markedly high yield strength and an enhanced plastic strain. In the CuZr-based metastable alloys investigated, there is an intimate relationship between the microstructure and the mechanical properties. The insights gained here should prove useful regarding the optimisation of the mechanical properties of bulk metallic glasses and bulk metallic glass composites.

The blending of polymers is a relatively inexpensive method of manipulating their properties and is common practice in the industry. Phosphate glass/polymer hybrids are an emerging class of nanomaterial with peculiar characteristics derived from nano-micro interactions of their components. Inorganic phosphate glasses are made up of chain-like molecules and are similar to polymer chains in their structure. These glasses are also unique in exhibiting similar processing temperatures to polymers, which opens up the possibility of co-processing and of greatly extending the range of obtainable properties. Both components being fluid during processing allow controlling and tailoring hybrid morphologies, and avoiding the problem of the intractable viscosity inherent from a high solid filler concentration. This work investigates the blending of an organic semi-crystalline polymer, polyamide 11 (PA 11), with different compositions of phosphate glasses. Experimental and theoretical studies of miscibility and phase behaviour of these unusual blends were analysed. In particular the research investigated the effect of glass composition on the rheological and thermo-chemical properties and nano/microstructure of these new materials, focusing on the tin fluoride (SnF2) content in the glasses. The Flory Huggins equilibrium depression point model was employed to correlate and predict miscibility behaviour in these new systems. The experimental results showed that a high amount of SnF2 could act as a proper compatibilizer for the novel Rilsan ® PA 11 matrix. Experiments showed that the halogen content lowered the glass transition temperature (Tg) and softening point (Ts) of the glasses, allowing both phases being fluid during melt-blending. However the water stability of the glasses was improved with increasing SnF2 content in the network. The particle size of glass in the hybrids was inversely correlated with SnF2 in the glass composition. This phenomenon resulted in lowering the equilibrium melting point (Tm0) in the hybrids. The load force (F) generated during the extrusion process and the hybrid viscosities decreased, without compromising chemical and thermal stability of the materials. The Tg of PA 11, measured as shifts of the major peak in dissipation factor against temperature plot, was inversely correlated with SnF2 content in the v glass composition, phenomenon often attributed to the partial miscibility of components in a system. The stiffness of the hybrid was improved by higher amount of SnF2 in the glass compositions with polyamide reinforced by the glass having the lowest Tg (60 SnF2 mol%). The longitudinal storage modulus was inversely correlated with temperature for PA 11 and all hybrids and increased with melting each phosphate glass with the polymer matrix. The storage modulus increased with SnF2 content in the glass composition in the matrix at lower temperature and reached a constant value for all hybrids at higher temperature. The viscosity and shear modulus decreased and increased respectively with increasing angular frequency. Shear modulus of polyamide matrix was lowered by each phosphate glass. All samples showed a small upturn in the modulus versus angular frequency curve at the lowest viscosities, behaviour related to the presence of yield stress in the hybrids, more evident in the hybrids with the highest content of SnF2 in the glass.

The static and dynamic flexural properties of a wood fiber matrix internally reinforced with continuous glass fibers were investigated. When modelled as a sandwich composite, the static flexural modulus of elasticity (MOE) of glass fiber reinforced hardboard could be successfully predicted from the static flexural MOE of the wood fiber matrix, and the tensile MOE and effective volume fraction of the glass fiber reinforcement. Under the same assumption, the composite modulus of rupture (MOR) is a function of the reinforcement tensile MOE and effective volume fraction, and the matrix stress at failure. The composite MOR was predicted on this basis with limited success. The static flexural modulus of elasticity, dynamic modulus of elasticity, and modulus of rupture of glass fiber reinforced hardboard increased with increasing effective reinforcement volume fraction. The logarithmic decrement of the composite decreased with increasing effective reinforcement volume fraction. Excellent linear correlation found among flexural properties determined in destructive static tests and nondestructive dynamic tests demonstrated the usefulness of dynamic test methods for flexural property evaluation. The short-term flexural creep behavior of glass fiber reinforced hardboard was accurately described by a 4-element linear viscoelastic model. Excellent agreement existed between predicted and observed creep deflections based on nonlinear regression estimates of model parameters.
Ph. D.

Silicate glasses are the most common glass types and have impact on almost every aspect in our lives: from window, containers, to glass fibers for telecommunications. Unlike their crystalline counterparts, glass materials lack long-range order in their atomic arrangement but their structures do possess short and medium range characteristics that play critical roles in their physical and chemical properties. Despite active development of characterization techniques that have contributed to the understanding of glass structures, there remain key challenges in obtaining essential structural features of glasses. Atomistic computer simulations have become an increasingly important method in elucidating the atomic structures and in interpretation and/or prediction of composition-structure-property relationships of complex materials. In this dissertation, classical molecular dynamic (MD) simulations were used to investigate the atomic structures, dynamic and other properties of two important glass systems—aluminosilicate glasses and borosilicate glasses, which are the basis of most industrial and technologically important glasses. Firstly, a comprehensive study of peralkaline Na2O-Al2O3-SiO2 glass with varying Al2O3/SiO2, Na2O/Al2O3, Na2O/SiO2 ratios has been performed to obtain better understanding of the composition–structure–property relationships in this glass system. More than 99% of Al were 4-coordinated in these glasses, validating that Na+ tend to charge balance [AlO4]- network forming units first and then, excess Na+ was used to create non-bridging oxygen (NBO) on Si. As the drop of Na/Al ratio, the percentage of NBO decreases, indicating an increase of the glass network connectivity. In addition, polyhedral connection probability results show that Al tend to be randomly distributed in the glass structure, suggesting a violation of Lowenstein's rule. These structural properties were further used to explain macroscopic properties of glass, such as change of glass transition temperature (Tg) and hardness (Hv) with glass composition. Secondly, molecular dynamics simulations were used to understand the structural, thermal mechanical and diffusion behaviors of spodumene (LiAlSi2O6) crystalline phases and glasses. It was found that β-LiAlSi2O6 has a structure much closer to the glass phase. The α-LiAlSi2O6 phase, however, has a more closed-packed structure and higher density. The diffusion behaviors were also found to be closely related to the atomic structures. Thirdly, the surface atomic structures of a series of sodium borosilicate glasses were studied using recently developed compositional dependent partial charge potentials. This provides insight into: a) the structural difference between glass surface and bulk glass; b) the evolution of bulk and surface structures as the change of glass composition. Lastly, pressure and temperature effects on the structure and properties of borosilicate glass were investigated in detail. A serial data derived from different compression temperatures and pressures enable us to explore the link between the microstructure and macroscopic physical properties. The results show that compression temperature and pressure play important roles in glass densification process and may result various glass densification mechanism. This dissertation demonstrates that atomistic simulations coupled with effective potentials and careful validations have become an effective method in research and design of complex glass materials.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1987.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 109-118.
by Dodd Harrison Grande.
Ph.D.

Soda-lime silicate glass (SLS glass) is one of the most commercialized glasses with a huge extent of applications from homewares and kitchenware appliance to cover for touchscreen gadgets. The latter has gained notable attentions recently since the majority of available touchscreen gadgets have covers from other glass families such as aluminosilicate. Technically, these types of glasses are difficult to produce and very costly, therefore, the prices of articles which are made by these glasses are high. In comparison, soda-lime silicate glass has lower price because of globally growing production and promising future. However, due to the intrinsic weaker mechanical properties, the application of SLS glass as cover of touchscreen gadgets is restricted. Several techniques have been applied to improve the mechanical properties of SLS glass. Among them chemical tempering is one the most promising technique. Typically, the chemical tempering is done by an ion-exchange process where sodium atoms contained in the glass are substituted by potassium ions diffusing from the molten salt. The effect of variables such as glass composition, molten bath composition, temperature, and time is crucial in the ion-exchange process. Particularly, selecting an unsuitable time and temperature of the process can affect mechanical properties of glass through a stress relaxation phenomenon. Therefore, optimization of the time and temperature can guarantee efficient reinforcement of glass. In this PhD research, three different temperatures (430°C, 450°C, and 470°C) and five different times (4 h, 8 h, 24 h, 48 h and 168 h) selected for chemical tempering of glass samples in pure molten KNO3 and molten KNO3 systematically poisoned by NaNO3. The compressive residual stress and case depth were determined by optical methods, the flexural strength was measured by a ring-on-ring test method and the surface chemical composition of the glass was analysed by Energy Dispersion X-ray Spectroscopy (EDXS). The resistivity of treated glass against forming surface cracks was studied by Vickers hardness and scratch test. To study the structural evolution, micro-Raman (μ-Raman) spectroscopy was used. The results pointed out that below addition of 0.5 wt% NaNO3, the ion-exchange process is always effective. Indeed, compressive residual stress, flexural strength, surface concentration and potassium penetration in Na-containing baths are substantially identical to values recorded on glasses treated in “pure” KNO3. Actually, case depth and interdiffusion coefficient are invariant with respect to the sodium content at least up to 1 wt%. No significative difference between “tin” and “air” side are revealed. Influence of time of tempering on Na-K exchange process showed that the concentration of K+ on the surface of glass was increased by increasing the duration of of the process. Compressive residual stress, on the other hand, was decreased by time due to the surface structural relaxation. A surface crack tendency under a Vickers indenter and scratch test gave the evident that K/Na ion-exchange process for more than 24 h is responsible for an indent mechanical reinforcement. A structural reorganization of the glass network occurred and a higher number of Q2 and Q3 species were present in the tempered glasses with respect to the pristine one. Such re-polymerization could account for a more plastic behavior under Vickers indentation and scratch test, making the material less susceptible to surface cracking. The case depth of tempered samples was increased by temperature at the expense of the compressive residual stress due to the stress relaxation. Relative concentration of K+ on the surface, as well, increased by the temperature. The increase in the temperature of ion-exchange process led to increase in the tendency of glass against formation of crack under Vickers indenter and scratch test. The limit of this propensity is tempering at 470 °C for 48 h as the formation of radial cracks and shorter plastic deformation regions under scratch test observed. From structural point of view, Na-K exchange caused reorganization of the glass network which is responsible for a more plastic behavior under Vickers indentation and scratch test.

Previous attempts to produce carbon nanotube (CNT) ceramic composites have resulted in poorly dispersed, unaligned and non-continuous CNTs in the composites with modest improvements in properties. The research presented in this thesis pertains to the production of dense aluminoborosilicate (ABS) glass matrix composites containing aligned and continuous multi- walled carbon nanotubes (MWCNT) of millimetre lengths. This was achieved by infiltrating CVD grown MWCNT preforms using a precursor sol and sintering which achieved 80 ± 2% dense composites. Focused ion beam milling together with image analysis showed that the composites contained 20 ± 2 vol.% MWCNTs, which are aligned and continuous within the glass matrix. Indentation studies showed greater damage tolerance in the composite compared to unreinforced ABS glass. Under compression, there is no significant change in the compressive strength between the composite and the unreinforced glass. The bend strength of microcantilever beams were 1.4 to 1.3 GPa for the composite and glass respectively. Elastic modulus of 84 GPa and fracture toughness (Kic of up to 2.4 MPa √m were obtained for the composite. The elastic modulus and fracture toughness results are an improvement of 30 % and 240 % over that of unreinforced ABS glass. Fracture surfaces showed apparent MWCNT pullout lengths of up to ~ 1 urn. Analysis indicates that crack bridging by intact MWCNTs provides the majority of the improvement in fracture toughness. Interlayer sliding of the MWCNTs and "sword in' sheath" failure mechanism of the MWCNTs prevented the maximum potential performance, with respect to elastic modulus and fracture toughness, from being achieved. Electrical conductivity in the alignment direction of the CNTs showed improvements by a factor of 106 compared to unreinforced ABS glass. Furthermore, improvement of a factor of ~ 10 in the thermal conductivity was obtained for the composite over that of ABS glass.

The research reported in this thesis deals mainly with the use of novel nanotechnology-based testing methods in the field of cement-based composites. The existing knowledge of indentation test methods is presented and reviewed. The research presented focuses on the development and pilot usage of depth-sensing indentation (DSI) test methods. The use of DSI test methods for cement-based materials covers two distinct areas. The first area includes the testing of micromechanical properties of cement pastes/matrices. The development in DSI test methods allows direct measurements of properties, such as hardness, elastic modulus, etc., at microscale. Special attention is paid to assessment of interfacial regions in such cement-based materials. In the second area, DSI test methods are used for assessment of interfacial properties of fibre reinforced cementitious composites, with focus being directed to composites reinforced by bundles of microfilaments. A new push-out test method for individual microfilaments collated in a bundle and embedded in cementitious matrix is proposed and developed. Novel use of other nanotechnology-based techniques, such as focused ion beam (FIB) techniques, forms another part of this thesis. The focused ion beam milling technique was utilised for production of diamond probes which enabled push-out tests of individual glass microfibres to be carried out. Also, FIB cross-sectioning of indents induced by DSI test methods was performed. This novel research method showed large potential for a better interpretation of the test and an improved understanding of the microfracture processes in cement-based materials. Detailed information about FIB techniques is therefore presented in a separate chapter. The focus of this project has been to develop methods which will enable further systematic research into micromechanical properties of cementitious materials and may lead to the ultimate goal of this investigation - the development of a new generation of materials of improved macromechanical properties and durability.

The marginal glass-forming alloys have attracted much attention due to unique products of devitrification with a very high number density of nuclei up to 10^23 m^-3. Among these alloy systems, utmost interest is given to Al-RE and Al-TM-RE alloys with excellent lightweight mechanical (fracture strength close to 1 GPa) and chemical properties attributed to the presence of an extremely high density of nanocrystals embedded in an amorphous matrix. Classical nucleation theory fails in explaining this abnormal nucleation behavior, several other mechanisms have been proposed
however, there is still no agreement on the exact nucleation mechanism. Al-Tb system was investigated in liquid and solid amorphous states with a collective study of ab-initio MD and RMC simulations and state of art X-rays and e-beam techniques. Regions of pure Al clusters in the solid and liquid states were detected with the sizes extending up to 1-2 nm length. Al clusters interconnecting regions lead to formation of RE rich MRO structure which gave rise to the pre-peak in S(Q)-Q data in liquid and solid states. Specimens having MRO were crystallized within a controlled atmosphere and temperature and investigated using a combined study of TEM, HRTEM, SEM, XRD and DSC. HRTEM investigations and JMA results indicated different mechanism of nucleation. Therefore the kinetics of highly populated nuclei formation was found too complicated to be explained by well-known JMA approach. Mechanical tests were applied to determine the effects of morphology and populations of nanocrystals embedded in amorphous matrix. The tensile tests and the subsequent fracture surface analysis indicated brittle type of failure and the formation of shear bands, respectively. Relatively high hardness and tensile strength were detected by nanocrystallization.

The nonlinear optical properties of a semiconductor-doped glass (SDG) channel waveguide were measured on a picosecond time-scale; namely, fluence-dependent changes in the absorption and the refractive index as well as the relaxation time of the nonlinearity. Slower, thermally-induced changes in the refractive index were also observed. The saturation of the changes in the absorption and the refractive index with increasing optical fluence is explained using a plasma model with bandfilling as the dominant mechanism. The fast relaxation time of the excited electron-hole plasma (20 ps) is explained using a surface-state recombination model. A figure of merit for a nonlinear directional coupler fabricated in a material with a saturable nonlinear refractive index is presented. The measured nonlinear change in the refractive index of the SDG saturates below the value required to effect fluence-dependent switching in a nonlinear directional coupler. Experiments with a channel-waveguide directional coupler support this prediction. However, absorption switching due to differential saturation of the absorption in the two arms of the directional coupler was observed.

博士
國立成功大學
物理學系
85
We have studied the physical properties of gallium microparticles embeded in porous glass .Near the temperature of superconducting phase transition,the main pattern of the X-ray does not fit in with any previously repoted phase of gallium .Even though sample resistance had two-stage superconducting phase transition correspond to 7 K and 6.3 K, but from the magnetic measurement there is only one superconducting phase transition at 6.3 K~6.4 K.Sample show complete diamagnetic behavior as whole volume were the same material. Magnetic moment had a abrupt change at 4.5 K to 4.4 K as sample cooling in magnetic field . We suggest that there was phase transition correspond to vortex lattice freezing. Temperature hysteresis between melting and freezing of vortex were observed. Magnetic hysteresis at high field range showed that gallium micropartiles formed grain by strong coupling. Magnetic hysteresis at low field range seemed that grains were coupled by Josephson weak links and sample behavior as a granular superconductor.

Optical properties of bismuth borate are measured for the composition range x Bi2O3 (1-x) B2O3, 0.25 < x < 0.65. The refractive indices increase as the bismuth content is increasing. Also the ultraviolet absorption edge was shown to shift to longer wavelengths. From these measurements a generalized Sellmeier formula was derived. Applying heat treatments to the prepared bismuth borate glasses in order to obtain glass ceramics leads in most cases to surface nucleation. It was proved that dopants increase the number of nucleating sites on the surfaces. On erbium-doped samples absorption and luminescence measurements were made. The Judd-Ofelt analysis revealed comparably high Judd-Ofelt coefficients. All coefficients were shown to decrease as the Bi2O3 content increases. The luminescence at 1550 nm reveals a broad and flat band which is narrowing with the increase in Bi2O3 content. The green upconversion was observed and the temporal behavior of the emission at 550 nm was investigated. The absorption and emission spectra of chromium-doped bismuth borate glasses were measured. On surface crystallized glasses, for x = 0.5 Bi2O3 and high chromium content, luminescence of chromate (CrO2-4) ion doped BiBO3 microcrystals was observed. Strontium barium niobate microcrystals embedded in strontium barium borate matrix were obtained by spontaneous nucleation in the melt and rapid quenching. Optical properties of Pb2B5O9Br based glass were also investigated. The heat treatment applied leads to the formation of small nanocrystals inside the glass.

碩士
國立中興大學
物理學系所
104
This experiment is for the secondary hardening chemical methods, the use of reverse engineering method from the etching→Grinding→Cutting pushed back the process to discuss the impact of all relevant factors secondary hardening. Process in the HF concentration because of etched glass and gradually decline, thereby affecting the etch rate, but itself if etching too long, will result in poor product appearance, and lack of etching the cracks can’t be eliminated or reduced, can not achieve the mechanical resistance to pressure increase purposes, If the glass cutting and grinding processes poorly, will produce a lot of> 100 um or more of crack extension (crack), because of the need to use the longer etching time, could have a substantial edge glass water ripples, resulting in poor appearance, If you choose to carry out high-density grinding wheel, reduce the degree of extension of cracks, may help repair two strong chemical effect, but the process is time consuming and costly, nor a mass productivity. Therefore, this study will be tested against the strengthening of the Management and control of secondary etching, grinding, cutting various conditions to 4PBT(4-Point Bending Test) analyze their respective conditions of AVG(Average) anti-stress and B10, to find the best conditions for strengthening.

abstract: This dissertation provides a fundamental understanding of the impact of bulk polymer properties on the nanometer length scale modulus. The elastic modulus of amorphous organic thin films is examined using a surface wrinkling technique. Potential correlations between thin film behavior and intrinsic properties such as flexibility and chain length are explored. Thermal properties, glass transition temperature (Tg) and the coefficient of thermal expansion, are examined along with the moduli of these thin films. It is found that the nanometer length scale behavior of flexible polymers correlates to its bulk Tg and not the polymers intrinsic size. It is also found that decreases in the modulus of ultrathin flexible films is not correlated with the observed Tg decrease in films of the same thickness. Techniques to circumvent reductions from bulk modulus were also demonstrated. However, as chain flexibility is reduced the modulus becomes thickness independent down to 10 nm. Similarly for this series minor reductions in Tg were obtained. To further understand the impact of the intrinsic size and processing conditions; this wrinkling instability was also utilized to determine the modulus of small organic electronic materials at various deposition conditions. Lastly, this wrinkling instability is exploited for development of poly furfuryl alcohol wrinkles. A two-step wrinkling process is developed via an acid catalyzed polymerization of a drop cast solution of furfuryl alcohol and photo acid generator. The ability to control the surface topology and tune the wrinkle wavelength with processing parameters such as substrate temperature and photo acid generator concentration is also demonstrated. Well-ordered linear, circular, and curvilinear patterns are also obtained by selective ultraviolet exposure and polymerization of the furfuryl alcohol film. As a carbon precursor a thorough understanding of this wrinkling instability can have applications in a wide variety of technologies.
Dissertation/Thesis
Ph.D. Chemical Engineering 2011

Borate glasses and glass-nano/microcrystal composite fabrication and investigations into their physical properties, have been interesting from their multifunctionalities view point. Certain borate structural units possess high hyperpolarizabilities and give rise to high nonlinear optical effects. High refractive index materials are important for photonic applications. Heavy metal oxide (Bi2O3) containing compounds have high refractive indices. Glasses embedded with wide band-gap semiconducting oxide crystals such as TiO2 received much attention due to their easy processing, stability and promising physical properties. Though TiO2 is used as nucleating agent to fabricate glass-ceramics of various phases, crystallization of TiO2 in glass matrices is difficult and the data are scarce in the literature. Therefore it was worth attempting to find glass compositions in which one can obtain TiO2 crystallization in large volume fractions. Towards this TiO2 crystallization was accomplished in BaO-TiO2-B2O3 glass matrix over wide composition ranges by tuning the concentration of BaO-TiO2 content in B2O3 network. The physical properties of these glasses of various compositions and glass-nanocrystal composites of TiO2 phase (anatase) were investigated. Interestingly BaO-TiO2-B2O3 glasses found to be hydrophobic in nature. The results obtained in the present research work are classified into five chapters apart from the Introduction, Materials and Methods chapters. Chapter 1 constitutes preface to oxide glasses, principles of glass formation and structural criteria followed by crystallization kinetics. In addition, principles of dielectric, optical and mechanical phenomena in glasses are discussed, since the present thesis focuses on the aforesaid physical properties. This chapter concludes with scope of the present thesis. Chapter 2 includes the detailed description concerning the fabrication techniques of materials under study and various characterization methods that have been employed at various stages of the present research work. The principles and experimental tools adopted for the structural and microstructural studies of materials were illustrated. Measurement techniques and experimental setup used to study physical parameters such as dielectric, optical, mechanical etc. were elaborated. Chapter 3 comprises structural, dielectric, electrical transport characteristics and optical studies of mixed alkali borate glasses in the 0.5Li2O-0.5M2O-2B2O3 (M=Li, Na and K) system. Transparent glasses in the Li2O-2B2O3 (LBO), 0.5Li2O-0.5Na2O-2B2O3 (LNBO) and 0.5Li2O-0.5K2O-2B2O3 (LKBO) were fabricated via the conventional melt quenching technique. Amorphous and glassy nature of the samples was confirmed via the X-ray powder diffraction and the differential scanning calorimetry, respectively. LKBO glass was found to have high thermal stability than that of LBO and LNBO. The frequency and temperature dependent characteristics of the dielectric relaxation and the electrical conductivity were investigated in the 100 Hz - 10 MHz frequency range. The relaxation and conductivity were rationalized using impedance and modulus formalism. Imaginary part of the electric modulus spectra was modelled using an approximate solution of Kohlrausch-Williams-Watts relation. The stretching exponent, β, was found to be temperature independent for LNBO glasses. Activation energies for conduction and relaxation process were calculated using the Arrhenius relation. The activation energy was found to be higher (1.25eV) for LKBO glasses than that of the other glass systems under study. This is attributed to the mixed cation effect. It has wide optical transmission window and optical band gap. Urbach energies were calculated for all these glasses. LBO, LNBO and LKBO glass compositions were found to crystallize in Li2B4O7, LiNaB4O7 and LiKB4O7 phases respectively upon heat treatment at appropriate temperatures. Transparent glass-micro crystal composites of LiKB4O7 were fabricated from LKBO glasses and found to be SHG active. BaO-TiO2-B2O3 Chapter 4 delineates the evolution of nanocrystalline TiO2 phase (Anatase) in BaO-TiO2-B2O3 (BTBO) glasses. Transparent colourless glasses in the ternary system were fabricated via conventional melt-quenching technique. The glasses with certain molar concentrations of BaO and TiO2 upon heat treatment at appropriate temperatures yielded nanocrystalline phase of TiO2 associated with the crystallite size in the 5-15 nm range. Nanocrystallized glasses exhibited high refractive index (no=2.15) at λ=543nm. These glasses were found to be hydrophobic in nature associated with the contact angle of 90o. These high index glass nanocrystal composites would be of potential interest for optical device applications. Crystallization kinetics of anatase phase in BTBO glasses were studied using non-isothermal Differential Scanning Calorimetry (DSC) at three different heating rates (10, 20 & 30 K/min). Scanning Electron Microscopy (SEM) carried out on heat treated (at 920 K) glasses confirmed bulk nucleation and three-dimensional growth. Johnson-Mehl-Avrami model could not be applied for this system suggesting considerable overlap of the nucleation and growth involving complex transformation process. However, modified Kissinger and Ozawa models were used to calculate the effective activation energy associated with anatase crystallization. The kinetic exponent n was found to be temperature dependent indicating the change in the crystallization mechanism. This is attributed to the high entropy fusion of anatase phase, fast crystallization rate and nano dimension of the anatase phase. Chapter 5 illustrates structural changes that occur in the x(BaO-TiO2)-B2O3 (x=0.25, 0.5, 0.75 &1 mol.) system on increasing the x apart from the details concerning some physical property correlations. Thermal stability and glass forming ability as determined by Differential Thermal Analysis (DTA) were found to increase with increasing BaO-TiO2 (BT) content. However, there was no noticeable change in the glass transition temperature (Tg). This was attributed to the active participation of TiO2 in the network formation especially at higher BT contents via the conversion of the TiO6 structural units into TiO4 units which increased the connectivity and resulted in an increase in crystallization temperature. Dielectric and optical properties at room temperature were studied for all the glasses under investigation. Interestingly, these glasses were found to be hydrophobic. The results obtained were correlated with different structural units present in the glass and their connectivity. These glasses exhibited low loss (tan δ≈0.002), frequency (10 kHz- 10 MHz) and temperature independent (or very weak temperature response) flat-dielectric response. Crossover temperature was encountered between flat response and Jonscher’s universal response. The cross-over temperature and cross-over energy barrier from flat dielectric response to Jonscher’s response was deduced for all the glasses in the present investigation. Electric modulus formalism was invoked to rationalize the relaxation phenomena. The observed dielectric response and conduction process in these glasses were attributed to the local vibration and switching of non-bridging oxygen ions in their potential cage and hopping over distributed energy barriers above the crossover temperature. Chapter 6 depicts the dielectric and mechanical properties of glasses embedded with TiO2 nanocrystals. BaO-TiO2-B2O3 glasses on subjecting to appropriate heat treatment temperature yielded TiO2 nano crystalline anatase phase. NMR studies carried out on the as-quenched glasses facilitated the estimation of fraction of tetrahedral and trigonal borate units. Poisson’s ratio and Young’s modulus were evaluated through theoretical expressions proposed by Makishima and Mackenzie. Nano-indentation and micro-indentation studies were carried out on the as-quenched glasses and glass-nanocrystal composites to examine mechanical characteristics. Estimated and indentation Young’s modulus of glasses were found to be in reasonable agreement. Hardness and Young’s modulus increased with increasing fraction of nano crystallites whereas fracture toughness was found to depend strongly on surface conditions. The results were corroborated by the structural units and particulates present in these glasses. Dielectric constant increased with increasing volume fraction of the nanocrystals which was rationalized via mixture rule. Chapter 7 describes the dielectric properties, electrical conduction and electric relaxation phenomena in 2Bi2O3-B2O3 (BBO) glasses followed by thier linear and nonlinear optical characteristics. Glasses in BBO system were obtained via melt-quenching technique. X-ray diffraction and differential scanning calorimetry were used to study the structural characteristics. Dielectric studies carried out on these glasses revealed near constant loss (NCL) response in the 1 kHz to 1 MHz frequency range at moderately high temperatures (300-450 K) accompanied by relatively low loss (tan δ=0.006, at 1 kHz & 300 K) and high dielectric constant (ε' =37, at 1 kHz & 300 K). The variation in AC conductivity with temperature at different frequencies showed a cross over from NCL response characterized by local ion vibration within the potential well to universal Jonscher’s power law dependence triggered by ion hopping between potential wells or cages. Thermal activation energy for single potential well was found to be 0.48±0.05 eV from cross over points. Ionic conduction and relaxation processes were rationalized by modulus formalism. The promising dielectric properties (relatively high ε' and low tan δ) of the BBO glasses were attributed to high density (93 % of its crystalline counterpart), high polarizability and low mobility associated with heavy metal cations, Bi3+. Optical band gap obtained for BBO glasses was found to be 2.6 eV. The refractive index measured for these glasses was 2.25±0.05 at λ=543 nm. Nonlinear refraction and absorption studies were carried out on BBO glasses using z-scan technique at λ=532 nm of 10 ns pulse width. The nonlinear refractive index obtained was n2=12.1x10-14 cm2/W and two-photon absorption coefficient was β=15.2 cm/GW. The n2 and β values of the BBO glasses were higher than that reported for high index bismuth based oxide glass systems in the literature. These were attributed to the high density, high linear refractive index, low band gap and two-photon absorption associated with these glasses. The electronic origin of large nonlinearities was discussed based on bond-orbital theory. Thesis ends with summary and conclusions followed by prospective views, though each chapter comprises conclusions associated with complete list of references. Patent, publications and conference proceedings that are listed below are largely based on the studies conducted as a part of the research work reported in the present thesis.

碩士
中國文化大學
應用化學研究所
86
The soldering procedure of sealing were examined by check the hermetical properties between soider glass and stainless steel. The chemical composition of these two kinds solder glass were determined by using ICP. At the same time,the thermal properties and crystallization behavior of solder glass were studied by DTA(differential thermal analysis). Then ,the heat treatment procedure of soldering was arranged by using the DTA thermogram .The devitrification mechanism and kinetic parameters of solder glass were investigated using non-isothermal technique(DTA) .Experimental results suggested that the devitrification mechanism of these two kinds solder glass were almost dominated by surface nucleation.The activation energies of devitrification solder glass were 56.04Kcal/mole for grey sample and 54.27Kcal/mole for blue one. This result were close to that of other kinds of solder glass. The expansion coefficient 、 possible crystalline phase 、spread capacity 、Vicker's hardness and hermetical properties of solder glass were also disscussed in this work .From the hermetical test, the leakage rate of sealing interface was found to be less than 1 × 10^-5atm.cc/ sec. It met the basic requirement of electric parts. This result showed the applicability of the procedure of heat treatment suggested in this work.

碩士
國立交通大學
光電工程研究所
84
CdS doped glass thin films were deposited onto SiO and Silicon substrates using RF sputtering techniques。The targets were prepared by sol-gel method。In the X-ray diffraction measurements were pointed out the thin films has hexagonnal wurtzite structure and the size of the crystallite were about 300 which is also conformed by SEM.In the transmission spectra showed the blueshifts increased when the size of the microcrystallites decreases。In the Raman spectra,we found that CdS doped glass thin films compared with target shifted to lower frequency。In the EPMA measurements,the ratio of S and Cd atoms( S/Cd)of the films was estimated to be 0.4~0.8。

碩士
國立聯合大學
材料科學工程學系碩士班
95
The objective of this study is to investigate the structure and properties of Bismuth zinc phosphate glasses. This study aims to examine of the properties of Bi2O3-ZnO-P2O5 glass by Bi2O3 replace ZnO. FTIR and Raman spectroscopies and NMR spectrum are employed to examine the structural changes of the glasses. Thermomechanical analysis was measured at heating rate of 10 oC/min for the determining heat properties of glass. Moreover, the relationship between properties and structural changes of the glasses with variations in Bi2O3 content will be established. The substitution of Bi2O3 for ZnO increases the molar volume and thermal expansion coefficient, but decreases the glass transition temperature, while enhancing the chemical durability of glasses. The XRD indicates that the crystalline phases, BiPO4 and Zn2P2O7, are formed in 10Bi2O3-(50-x)ZnO-40P2O5 glass. FTIR and Raman spectroscopies and NMR examine the structural changes with the compositions of the glasses. As Bi2O3 replaces ZnO, the phosphate chain length decreases while P-O-Bi linkages and BiO6 units form in the network of the glasses.

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. This report discusses two aspects of research on bulk metallic glasses. The first is an effort to increase their toughness by combining them with reinforcement to form a composite. The second is the first direct measurement of plane strain fracture toughness of bulk metallic glass. Particulate and continuous fiber reinforced composite materials were fabricated using bulk metallic glass as the matrix. The particulate composites combined W, WC, SiC and Ta reinforcements in a matrix with the composition Zr57Nb5Al10Cu15.4Ni12.6. Continuous fiber composites were fabricated using W and 1080 carbon steel (music) wire reinforcement in a Zr41.25Ti13.75Cu12.5Ni10Be22.5 matrix. In both cases the metallic glass remained amorphous during processing. Compressive strain to failure was greatly enhanced in both particulate and continuous fiber composites by the formation of multiple shear bands. Tungsten reinforcement provided the greatest improvement. The tungsten is wet well by the metallic glass, and forms a strong interface. Both particulate and fiber reinforced composite showed improved tensile properties. Energy (per unit volume) to break increased 52% for 5% Vf, 150 [...] W reinforced Zr57Nb5Al10Cu15.4Ni12.6 and 18% for 60% Vf music wire reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5. Tightly bonded ductile particles and weakly bonded continuous fibers proved best for enhancing the tensile properties of bulk metallic glass. Fracture toughness of the unreinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 bulk metallic glass was determined using 3-point bend measurements and coherent gradient sensing (CGS). The measured fracture toughness is nominally 55 [...]. Once initiated, cracks in the unreinforced metallic glass propagated in an unstable manner. Continuous fiber reinforcement was demonstrated to arrest crack propagation in 3-point bend fracture tests of bulk metallic glass matrix composites.