Download or read book Structural Analysis of Metallic Glasses with Computational Homology written by Akihiko Hirata and published by Springer. This book was released on 2016-04-05 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the application of computational homology for structural analysis of metallic glasses. Metallic glasses, relatively new materials in the field of metals, are the next-generation structural and functional materials owing to their excellent properties. To understand their properties and to develop novel metallic glass materials, it is necessary to uncover their atomic structures which have no periodicity, unlike crystals. Although many experimental and simulation studies have been performed to reveal the structures, it is extremely difficult to perceive a relationship between structures and properties without an appropriate point of view, or language. The purpose here is to show how a new approach using computational homology gives a useful insight into the interpretation of atomic structures. It is noted that computational homology has rapidly developed and is now widely applied for various data analyses. The book begins with a brief basic survey of metallic glasses and computational homology, then goes on to the detailed procedures and interpretation of computational homology analysis for metallic glasses. Understandable and readable information for both materials scientists and mathematicians is also provided.

Download or read book Bulk Metallic Glasses written by C. Suryanarayana and published by CRC Press. This book was released on 2017-11-22 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the fast pace of research in the field, the Second Edition of Bulk Metallic Glasses has been thoroughly updated and remains essential reading on the subject. It incorporates major advances in glass forming ability, corrosion behavior, and mechanical properties. Several of the newly proposed criteria to predict the glass-forming ability of alloys have been discussed. All other areas covered in this book have been updated, with special emphasis on topics where significant advances have occurred. These include processing of hierarchical surface structures and synthesis of nanophase composites using the chemical behavior of bulk metallic glasses and the development of novel bulk metallic glasses with high-strength and high-ductility and superelastic behavior. New topics such as high-entropy bulk metallic glasses, nanoporous alloys, novel nanocrystalline alloys, and soft magnetic glassy alloys with high saturation magnetization have also been discussed. Novel applications, such as metallic glassy screw bolts, surface coatings, hyperthermia glasses, ultra-thin mirrors and pressure sensors, mobile phone casing, and degradable biomedical materials, are described. Authored by the world’s foremost experts on bulk metallic glasses, this new edition endures as an indispensable reference and continues to be a one-stop resource on all aspects of bulk metallic glasses.

Download or read book A New Direction in Mathematics for Materials Science written by Susumu Ikeda and published by Springer. This book was released on 2015-12-08 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the first volume of the SpringerBriefs in the Mathematics of Materials and provides a comprehensive guide to the interaction of mathematics with materials science. The anterior part of the book describes a selected history of materials science as well as the interaction between mathematics and materials in history. The emergence of materials science was itself a result of an interdisciplinary movement in the 1950s and 1960s. Materials science was formed by the integration of metallurgy, polymer science, ceramics, solid state physics, and related disciplines. We believe that such historical background helps readers to understand the importance of interdisciplinary interaction such as mathematics–materials science collaboration. The middle part of the book describes mathematical ideas and methods that can be applied to materials problems and introduces some examples of specific studies—for example, computational homology applied to structural analysis of glassy materials, stochastic models for the formation process of materials, new geometric measures for finite carbon nanotube molecules, mathematical technique predicting a molecular magnet, and network analysis of nanoporous materials. The details of these works will be shown in the subsequent volumes of this SpringerBriefs in the Mathematics of Materials series by the individual authors. The posterior section of the book presents how breakthroughs based on mathematics–materials science collaborations can emerge. The authors' argument is supported by the experiences at the Advanced Institute for Materials Research (AIMR), where many researchers from various fields gathered and tackled interdisciplinary research.

Download or read book Metallic Glasses and Their Composites written by D.V. Louzguine and published by Materials Research Forum LLC. This book was released on 2018-01-02 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation of metallic glasses and dual-phase composite/hybrid materials is reviewed, as well as the glass transition process and the resulting structural phenomena. These materials exhibit high strength, extreme hardness, good wear resistance and large elastic deformation. Due to their excellent structural, functional, magnetic, chemical and biological properties metallic glasses are suitable for a great many applications, including in such areas as microelectromechanical devices, pressure sensors, orthopaedic screws and precision surgical instruments. Metallic Glasses, Metallic Glass Composites, Crystal/Glass Transition, Nano-Crystallization, Phase Separations, Supercooled Liquids, Glassy Nanocomposites, Nanoscale Quasicrystals, Mechanical Properties, Nanoscale Wear Resistance, Bauschinger Effect, Cryogenic Temperature, Porous Glasses, Nanocomposite Alloys, Soft Magnetic Alloys, Hard Magnetic Alloys, Magnetocaloric Effect, Corrosion Resistant Alloys, Surface Oxides, Catalysts

Download or read book Microstructure Property Optimization in Metallic Glasses written by Baran Sarac and published by Springer. This book was released on 2015-03-12 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis consists of an in-depth study of investigating microstructure-property relationships in bulk metallic glasses using a novel quantitative approach by which influence of the second phase features on mechanical properties can be independently and systematically analyzed. The author evaluates and optimizes the elastic and plastic deformation, as well as the overall toughness of cellular honeycombs under in-plane compression and porous heterostructures under uniaxial tension. The study reveals three major deformation zones in cellular metallic glass structures, where deformation changes from collective buckling showing non-linear elasticity to localized failure exhibiting a brittle-like deformation, and finally to global sudden failure with negligible plasticity as the length to thickness ratio of the ligaments increases. The author found that spacing and size of the pores, the pore configuration within the matrix, and the overall width of the sample determines the extent of deformation, where the optimized values are attained for pore diameter to spacing ratio of one with AB type pore stacking.

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 Experimental and Computational Investigations of Strain Localization in Metallic Glasses written by Ashwini Bharathula and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Metallic glasses are metallic alloy systems with disordered atomic structure. Due to their unique amorphous structure, they exhibit an extraordinary set of properties that are ideal for a wide variety of applications ranging from electrical transformers, armor-piercing projectiles, sporting goods and fuel cells to precision gears for micromotors. In particular, owing to their exceptional mechanical properties like near-theoretical strength (1-3 GPa), large elastic strain range (2-3%), and unusual formability above the glass transition temperature, metallic glasses have tremendous potential in structural applications. Unfortunately, their unique structure also gives rise to significant limitations, such as limited ductility at room temperature due to rapid localization of plastic flow in shear bands. However, when the test volumes approach the size of a shear band nucleus (~50-500 nm), it is believed that shear band formation and propagation can be constrained, leading to enhanced plasticity and failure strength. This study investigates the phenomenon of strain localization using both experimental and computational techniques. On the experimental front, sample size effects on strength, plasticity and deformation modes were explored in a Zr-based bulk metallic glass via micron- and sub-micron scale compression testing. Specimens with diameters ranging from 200 nm to a few microns were fabricated using Focused Ion Beam technique and were tested under uniaxial compression in a nanoindentation set-up with a flat punch tip. Effect of extrinsic factors like specimen geometry and machine stiffness on deformation behavior was discussed. Shear banding was shown to be more stable at this length scale than in macro-scale testing because of a smaller specimen to load frame stiffness ratio. It was found that as the specimen size is reduced to below 300 nm, the deformation mode changes from being discrete and inhomogeneous to more continuous flow including both localized and non-localized contributions at low strains. Moreover, the magnitude of strain bursts was found to decrease with decrease in specimen size. Furthermore, Weibull statistical analysis was performed to investigate the effect of specimen size on yield strength in this metallic glass. It was revealed that the dispersion in strengths increases dramatically with decrease in sample size, attributed to the size distribution of the defects responsible for shear banding. The findings are crucial in designing systems which promote plasticity in metallic glasses by suppressing the shear-band instability and also in direct application of these materials for structural purposes as small components in micro- and nano-scale systems. On the computational front, Molecular Dynamics (MD) simulations have been employed to generate Zr-Cu metallic glass structures. In order to analyze and better understand and visualize the concepts of "free" volume and flow defects in metallic glasses, an electron density model was developed as an upgrade to the traditional hard sphere approaches. Simple tension and shear modes of deformation were simulated using MD in Zr-Cu system, and role of open volume in deformation was studied using the electron density model. In uniaxial tension simulations, effect of temperature and deformation rate is examined, and the process of accumulation of free volume to the point of catastrophic failure is visualized using the Electron Density model. In shear simulations, we find that the as-quenched glass structures undergo homogeneous deformation and do not exhibit any strain localization. However, it is found that by incorporating a cylindrical void in the glass structure as a source of "free" volume, it is possible to induce strain localization. It was found that a critical void diameter of 8 Angstroms was required to successfully initialize strain localization in this system.

Download or read book Experimental and Computational Investigations of Structure and Plastic Flow in Bulk Metallic Glasses written by Matthew James Lambert and published by . This book was released on 2005 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Thermo-mechanical processing of metallic glasses has been shown to change the free volume and have some effect on the mechanical properties. In order to better quantify these effects, we have studied the homogeneous flow of metallic glasses and the subsequent changes in atomic ordering, in terms of free volume and x-ray measurements, and mechanical properties via nanoindentation. The internal free volume of the specimens, as measured through changes in the specific heat by differential scanning calorimetry, has been shown to increase with increasing levels of total strain in tension and in compression. X-ray diffraction of amorphous specimens in the as-cast, annealed, and homogeneously deformed state also showed a change in the short-range atomic order of the alloy. The shape of the x-ray patterns for the as-cast and annealed states were nearly identical, while a decrease in intensity of x-rays was seen at high angles of 2[theta] in the homogeneously deformed samples. These high angles describe a change in the state of the short-range order. Nanoindentation has shown slight changes in the elastic properties and density of serrations in amorphous materials with changes in the free volume. Using available embedded atom method potentials, molecular dynamics simulations of several Cu-Zr binary, a Cu-Zr-Al ternary, and a quinternary Zr-Cu-Ni-Al-Ti alloy systems at multiple quench rates from the liquid were performed. Using an annealing/quenching technique that allows the simulation of even extremely slow quench rates, glassy structures of these alloys were produced at varying quench rates and their nearest-neighbor coordination examined. Radial distribution functions of the modeled systems show excellent agreement with experimental data, suggesting that the predicted atomic structure should have realistic features similar to real materials. The glass transition temperatures of several of these alloys were determined through a simulated dilatometry technique. Comparing the features and changes in the nearest-neighbor order and the simulated glass transitions with available experimental data, we found a novel set of criteria to predict the effect of changes in alloy composition on glass forming ability. The change in the distribution of nearest neighbors with quench rate, as compared in alloys with different experimentally determined glass forming abilities, did only provide some insights into the formation of glasses. However, the measurement of the fraction of atomic pairs that exhibited icosahedral-like short-range order was found to be directly related to the relative glass forming abilities of the alloys simulated.

Download or read book High throughput Experimental and Computational Investigations of Metallic Glass Structure and Glass Forming Ability written by Juan Wang (Mechanical engineer) and published by . This book was released on 2018 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite intense interest, identifying the structural origin of glass forming ability in metallic alloys remains a challenge due to the difficulty of describing the evolution of the long-range disordered structure from the liquid. In this thesis, we integrate high-throughput experimental methods with computational simulations to study glass formation and the resulting mechanical properties, with a primary focus on the Al-Ni-Zr system. Based on our investigation of the structural and cluster evolution using molecular dynamics simulations, we report the variance of the fraction of different types of atomic clusters in the liquid as a potential parameter to predict glass formation. The predictive power of the variance in the liquid state was verified by comparison with alloy libraries synthesized by a highly efficient laser deposition technique. Experimentally, glass formation was found over a wide compositional range centered on Al21.4Ni23.9Zr54.7, which is in excellent agreement with the simulations. Because the variance of cluster fractions at temperatures above the crystallization temperature is independent of quench rate as well as any particular cluster type, we believe this method could be extended to any alloy system, including those of higher complexity.Building upon this work, we examine the fundamental factors that determine the distribution and volume fraction of the crystal nucleation in simulated Al20Ni60Zr20 metallic glass/crystalline composites. The results show that the initial distribution of the atoms does not contribute to the final faction of atoms that form BCC-coordinated crystals in the composite. However, one major factor that affects the crystalline fraction is the temperature at which the stable nuclei form. The stability of Al-centered 0, 3, 6, 4 clusters also plays an important role in the final percentage of the ordered atoms.Finally, nanoindentation was performed to identify trends in hardness and indentation modulus with composition. The relationship between cluster structure and the observed mechanical behavior was evaluated by molecular dynamic simulation in Al-Ni-Zr system. By addressing the local mechanical property-cluster structure-glass forming ability relationship in this system, this study expands the understanding of the relationship of atomic structure, macroscopic mechanical behavior and glass forming ability.

Download or read book An Introduction to Metallic Glasses and Amorphous Metals written by Zbigniew H. Stachurski and published by Elsevier. This book was released on 2021-07-28 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Introduction to Metallic Glasses and Amorphous Metals gives a background on the physics of materials, describing relevant experimental techniques. The book presents the necessary background in physics, thermodynamics, and the mechanics of solids, before moving on to cover elasticity, plasticity, fracture and the anelastic behavior of metallic glasses, relating these properties to chemical composition, atomic arrangement, microstructure, and methods of preparation. In addition, it compares the structure-property relationships specific to metallic glasses with polycrystalline metals and alloys and describes the properties and characteristics of metallic glasses. The general features and behavior of metallic glasses are also analyzed and summarized. The book includes full derivations of theory and equations and presents a compendium of experimental methods used in materials science to characterize and study metallic glasses and amorphous solids. The title is a comprehensive resource for any researcher interested in the materials science of metallic glasses and amorphous materials. - Presents the fundamental materials science needed to understand amorphous metals, metallic glasses and alloys - Details manufacturing techniques for metallic glasses - Gives the mechanical properties of metallic glasses - Illustrates concepts with detailed tables and graphs - Contains a compendium of experimental methods for use with amorphous metals and metallic glasses

Download or read book Computational Study of Vanadate and Bulk Metallic Glasses written by Anupriya Agrawal and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Finally, the deformation behavior of metal-metallic glass composites was explored for the cases where the crystal is the stronger and weaker phase, respectively. For this we have studied Cu-(Cu65Zr35Ti5) nano-laminates with copper as the stronger phase and Al-(Cu45Zr45Al10) nano-laminates where the glass is the stronger phase. The effect of orientation of the crystal relative to the interface, the loading direction, the annealing temperature and the crystal volume percent was also investigated.

Download or read book Metallic Glasses written by Behrooz Movahedi and published by BoD – Books on Demand. This book was released on 2016-08-17 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallic glasses and amorphous materials have attracted much more attention in the last two decades. A noncrystalline solid produced by continuous cooling from the liquid state is known as a glass. From the other point of view, a noncrystalline material, obtained by any other process, for example, vapor deposition or solid-state processing methods such as mechanical alloying, but not directly from the liquid state, is referred to as an amorphous material. At this moment, bulk metallic glasses (BMG) are appearing as a new class of metallic materials with unique physical and mechanical properties for structural and functional usage. Extreme values of strength, fracture toughness, magnetic properties, corrosion resistance, and other properties have been registered in BMG materials.

Download or read book Polyhedra based Analysis of Computer Simulated Amorphous Structures written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Bulk metallic glasses represent a newly developed class of materials. Some metallic glasses possess combinations of very good or even excellent mechanical, chemical and/or magnetic properties uncovering a broad range of both industrial and vital applications. Besides all advantages metallic glasses have also significant drawbacks, which have to be overcome for commercial application. Apart from low critical thicknesses, brittleness and chemical inhomogeneity one important problem of metallic glasses is the lack of an appropriate theory describing their structure. Therefore, the search for new glass forming compositions as well as the improving of existing ones occurs at present by means of trial-and-error methods and a number of empirical rules. Empirical rules for good glass-forming ability of bulk metallic glasses have been established in recent years by Inoue and Egami. Two of these rules, (i) Preference of more than 3 elements and (ii) Need of more than 12 % radii difference of base elements, seem to be closely related to topological (geometrical) criteria. From this point of view topological parameters contribute essentially to the glass-forming ability. The third rule (iii) demands a negative mixing enthalpy of base elements and refers to the chemical interaction of the atoms. The generalized Bernal's model (hard-sphere approximation) was used for the simulation of monatomic, binary and multi-component structures. Excluding chemical interaction, this method allows the investigation of topological criteria of the glass-forming ability. Bernal's hard-sphere model was shown to be a good approximation for bulk metallic glasses and metallic liquids and yields good coincidence of experimental and theoretical results." The Laguerre (weighted Voronoi) tessellation technique was used as the main tool for the structural analysis. Due to very complex structures it is impossible to determine the structure of bulk metallic glasses by means of standard crystallographic met.

Download or read book Local Structure Analysis of Model Metal metal and Metal metalloid Metallic Glasses written by Jason J. Maldonis and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Materials scientists lack a general, abstract description of the atomic structure of metallic glasses (MGs). Structural descriptions developed for crystals and crystal defects are ineffective because the amorphous structure of MGs does not exhibit the necessary translation and rotational symmetries, and structure descriptions developed for oxide glasses are ineffective due to the lack of strong covalent bonds in MGs and the higher coordination number of local structures, which allows for more structural diversity. This thesis reports research on improved abstract descriptions of MG structure developed by studying both the short- and medium-range order (SRO and MRO) of simulated MGs. Hybrid reverse Monte Carlo (HRMC) simulations were used to generate MG structures with realistic MRO and molecular dynamics (MD) simulations were used to generate MG structures with low energy. In Zr-Cu-Al, a metal-metal system, subcritical fcc-like MRO exists at the nanometer scale, and better glass forming alloys can be creating by destabilizing crystal-like SRO and MRO. In the Pd82Si18 metal-metalloid system, an fcc-like region also exists, but the structure is more complicated and cannot be explained by typical topological structure metrics. A new structure metric called motif extraction based on geometry rather than topology was developed to characterize the local structure of MGs. Motif extraction applied to a canonical metal-metal glass, Zr50Cu45Al5, quenched via MD, reproduces results obtained from topological approaches and identifies a hierarchy of structures as a function of coordination number that is focused around icosahedral geometries, which are dominant in metal-metal glasses. An analogous hierarchy of structures is found in HRMC models of Zr50Cu35Al15 that focuses around fcc geometries. This suggests that one or two motifs may fundamentally dominate the structure of both glassy and crystal-like SRO in MGs.

Download or read book Bulk Metallic Glasses written by Thomas F. George and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An amorphous metal is a metallic material with a disordered atomic-scale structure. In contrast to most metals, which are crystalline and therefore have a highly ordered arrangement of atoms, amorphous alloys are non-crystalline. This book presents and reviews research in the study of bulk metallic glasses.

Download or read book The Structural Study of Metallic Glasses Using Variable Two theta and Variable Energy X ray Diffraction Techniques written by Dokyol Lee and published by . This book was released on 1980 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Studies of Metal Doped Phosphate Glasses and Computational Developments in Diffraction Analysis written by Robert M. Moss and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: