Download or read book A Molecular Dynamics Study of Nanocontact Plasticity and Dislocation Avalanches in FCC and BCC Crystals written by Javier Varillas and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study aims to investigate the underlying mechanisms which govern the development of dense defect networks in nanoscale crystal plasticity, either under contact and uniaxial loading conditions, with emphasis on the onset of intermittent avalanche phenomena. The investigation is based on a comprehensive set of massive molecular dynamics (MD) simulations performed with embedded-atom method potentials in face-centered cubic (FCC) and body-centered cubic (BCC) crystals. The first part of the thesis concerns the combined role of elasticity and plasticity in nanocontact loadings, where attention is given to the mechanisms leading to the formation of a permanent nanoimprint as well as to the onset of material pile-up at the contact vicinity. It is found that the topographical arrangement of the slip traces emitted at the surface into specific deformation patterns is a distinctive feature of the underlying dislocation glide and twinning processes occurring in FCC and BCC crystals as a function of temperature and surface orientation. A mechanistic analysis is made on the influence of the defect nucleation events in conjunction with the development of entangled defect networks upon the material hardness and its evolution towards a plateau level with increasing indenter-tip penetration. Complementary MD simulations of the uniaxial stress-strain curve of the plastically deformed region are carried out with the purpose of establishing a direct correlation between nanoscale material responses attaining under uniaxial and contact loading conditions. The results of this comparison illustrate on the key role played by defect nucleation processes on the formation of permanent nanoimprints, which differs from the conventional view in that in micro and macroscopic scales imprint formation is essentially governed by the evolutionary character of a preexisting (entangled) defect network: the greater the dislocation density, the larger the measured hardness. In overall, this work provides a fundamental insight into the understanding of why BCC surfaces are harder than FCC surfaces at the nanoscale. A statistical physics background is devised to investigate the influence of the dislocation mechanisms on the onset of avalanche events that are inherent to crystal plasticity. The analysis is predicated upon the notion in that the size distribution of such avalanches follows power-law scaling. To investigate the avalanche size distributions in cubic crystals, a group of novel MD simulations are performed where the computational cells containing a periodic arrangement of a preexisting dislocation network are subjected to uniaxial straining under displacement control at different strain rates and temperatures. Under sufficiently slow driving, the dislocation networks evolve through the emission of dislocation avalanches which do not overlap in time. This illustrates that the mobilized entangled dislocation arrangements exhibit quiescent periods during each plastic (dissipative) event, enabling comparison with experimental results which are also performed under strict displacement controlled conditions. The results illustrate on the attainment of a transitional slip size separating two power-law avalanche regimes as a function of the fundamental dislocation glide processes at the crossroads of self-organized and tuned criticality models. Detailed analyses of the MD simulations furnish specific mechanisms characterizing dislocation avalanche emission and propagation in FCC and BCC metals throughout a wide temperature range, which is central in supporting the onset of the aforementioned two power-law regimes.
Download or read book Using Molecular Dynamics to Develop a Crystal Plasticity Model for BCC Slip written by and published by . This book was released on 2013 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dislocations and Plasticity in Bcc Transition Metals at High Pressure written by and published by . This book was released on 2009 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using first-principles electronic structure calculations, quantum-based atomistic simulations and atomistically informed dislocation dynamics (DD) simulations, we have studied individual dislocation behavior and the multiscale modeling of single-crystal plasticity in the prototype bcc transition metals Ta, Mo and V under both ambient and high pressure conditions. The primary focus in this work is on the pressure-dependent structure, mobility and interaction of a/2111 screw dislocations, which dominate the plastic deformation properties of these materials. At the electronic scale, first-principles calculations of elasticity, ideal strength and generalized stacking fault energy surfaces have been used to validate quantum-based multi-ion interatomic potentials. At the atomistic scale, these potentials have been used in flexible Green's function boundary condition simulations to study the core structure, Peierls stress?{sub P}, thermally activated kink-pair formation and mobility below?{sub P}, and phonon-drag mobility above?{sub P}. These results have then been distilled into analytic velocity laws and used directly in predictive microscale DD simulations of flow stress and resolved yield stress over wide ranges of pressure, temperature and strain rate.
Download or read book Stochastic Thermodynamics written by Luca Peliti and published by Princeton University Press. This book was released on 2021-07-06 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive graduate-level introduction to stochastic thermodynamics Stochastic thermodynamics is a well-defined subfield of statistical physics that aims to interpret thermodynamic concepts for systems ranging in size from a few to hundreds of nanometers, the behavior of which is inherently random due to thermal fluctuations. This growing field therefore describes the nonequilibrium dynamics of small systems, such as artificial nanodevices and biological molecular machines, which are of increasing scientific and technological relevance. This textbook provides an up-to-date pedagogical introduction to stochastic thermodynamics, guiding readers from basic concepts in statistical physics, probability theory, and thermodynamics to the most recent developments in the field. Gradually building up to more advanced material, the authors consistently prioritize simplicity and clarity over exhaustiveness and focus on the development of readers’ physical insight over mathematical formalism. This approach allows the reader to grow as the book proceeds, helping interested young scientists to enter the field with less effort and to contribute to its ongoing vibrant development. Chapters provide exercises to complement and reinforce learning. Appropriate for graduate students in physics and biophysics, as well as researchers, Stochastic Thermodynamics serves as an excellent initiation to this rapidly evolving field. Emphasizes a pedagogical approach to the subject Highlights connections with the thermodynamics of information Pays special attention to molecular biophysics applications Privileges physical intuition over mathematical formalism Solutions manual available on request for instructors adopting the book in a course
Download or read book Nanoindentation written by Anthony C. Fischer-Cripps and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new edition of Nanoindentation includes a dedicated chapter on thin films, new material on dynamic analysis and creep, accounts of recent research, and three new appendices on nonlinear least squares fitting, frequently asked questions, and specifications for a nanoindentation instrument. Nanoindentation Second Edition is intended for those who are entering the field for the first time and to act as a reference for those already conversant with the technique.
Download or read book Applied Nanoindentation in Advanced Materials written by Atul Tiwari and published by John Wiley & Sons. This book was released on 2017-10-30 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research in the area of nanoindentation has gained significant momentum in recent years, but there are very few books currently available which can educate researchers on the application aspects of this technique in various areas of materials science. Applied Nanoindentation in Advanced Materials addresses this need and is a comprehensive, self-contained reference covering applied aspects of nanoindentation in advanced materials. With contributions from leading researchers in the field, this book is divided into three parts. Part one covers innovations and analysis, and parts two and three examine the application and evaluation of soft and ceramic-like materials respectively. Key features: A one stop solution for scholars and researchers to learn applied aspects of nanoindentation Contains contributions from leading researchers in the field Includes the analysis of key properties that can be studied using the nanoindentation technique Covers recent innovations Includes worked examples Applied Nanoindentation in Advanced Materials is an ideal reference for researchers and practitioners working in the areas of nanotechnology and nanomechanics, and is also a useful source of information for graduate students in mechanical and materials engineering, and chemistry. This book also contains a wealth of information for scientists and engineers interested in mathematical modelling and simulations related to nanoindentation testing and analysis.
Download or read book High Entropy Materials written by Yong Zhang and published by Springer. This book was released on 2019-05-27 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book draws on the latest research to discuss the history and development of high-entropy alloys and ceramics in bulk, film, and fiber form. High-entropy materials have recently been developed using the entropy of mixing and entropy of configuration of materials, and have proven to exhibit unique properties superior to those of conventional materials. The field of high-entropy alloys was born in 2004, and has since been developed for both scientific and engineering applications. Although there is extensive literature, this field is rapidly transforming. This book highlights the cutting edge of high-entropy materials, including their fundamentals and applications. Above all, it reflects two major milestones in their development: the equi-atomic ratio single-phase high-entropy alloys; and the non-equi-atomic ratio dual-phase high-entropy alloys.
Download or read book Stochastic Energetics written by Ken Sekimoto and published by Springer. This book was released on 2010-03-10 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stochastic Energetics by now commonly designates the emerging field that bridges the gap between stochastic dynamical processes and thermodynamics. Triggered by the vast improvements in spatio-temporal resolution in nanotechnology, stochastic energetics develops a framework for quantifying individual realizations of a stochastic process on the mesoscopic scale of thermal fluctuations. This is needed to answer such novel questions as: Can one cool a drop of water by agitating an immersed nano-particle? How does heat flow if a Brownian particle pulls a polymer chain? Can one measure the free-energy of a system through a single realization of the associated stochastic process? This book will take the reader gradually from the basics to the applications: Part I provides the necessary background from stochastic dynamics (Langevin, master equation), Part II introduces how stochastic energetics describes such basic notions as heat and work on the mesoscopic scale, Part III details several applications, such as control and detection processes, as well as free-energy transducers. It aims in particular at researchers and graduate students working in the fields of nanoscience and technology.
Download or read book Statistical Mechanics written by Giovanni Gallavotti and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: This clear book presents a critical and modern analysis of the conceptual foundations of statistical mechanics as laid down in Boltzmann's works. The author emphasises the relation between microscopic reversibility and macroscopic irreversibility, explaining fundamental concepts in detail.
Download or read book Structure and Properties of Polymers written by and published by . This book was released on 1993 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Composite Materials Technology written by S.M. Sapuan and published by CRC Press. This book was released on 2009-12-23 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Artificial neural networks (ANN) can provide new insight into the study of composite materials and can normally be combined with other artificial intelligence tools such as expert system, genetic algorithm, and fuzzy logic. Because research on this field is very new, there is only a limited amount of published literature on the subject.Compiling in
Download or read book Nanostructured Materials written by Gan-Moog Chow and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: A critical, up to date, tutorial review and discussion of the science and technology of nanostructured metallic and ceramic materials. The focus is on the synthesis and processing of nanoparticles, the assembly and stability of nanostructures, characterization and properties, and applications. There is a growing interest in the processing of nanoparticles into consolidated bulk materials and coatings. The metastability of nanoparticles may lead to undesirable grain growth during thermally assisted consolidation or other processing routes, and the retention of nanostructures in a processed part or component continues to attract a great deal of attention. Current activity is concentrating on the deposition of nanostructured coatings using established thermal spray technology and wet chemistry methods. Naturally existing or artificially synthesized templates with unique structures and morphologies have been used to fabricate nanostructured materials with the same structural and morphological characteristics as the templates. Recent advances in characterization techniques have provided information on the structure, the surface and bulk chemistry of nanoparticles, and the structures and chemistry of exposed and buried surfaces of coatings. Contributors are drawn from Canada, France, UK, USA, Belarus, Russia and Ukraine.
Download or read book 3D Printing of Metals written by Manoj Gupta and published by MDPI. This book was released on 2019-08-13 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: 3D printing is rapidly emerging as a key manufacturing technique that is capable of serving a wide spectrum of applications, ranging from engineering to biomedical sectors. Its ability to form both simple and intricate shapes through computer-controlled graphics enables it to create a niche in the manufacturing sector. Key challenges remain, and a great deal of research is required to develop 3D printing technology for all classes of materials including polymers, metals, ceramics, and composites. In view of the growing importance of 3D manufacturing worldwide, this Special Issue aims to seek original articles to further assist in the development of this promising technology from both scientific and technological perspectives. Targeted reviews, including mini-reviews, are also welcome, as they play a crucial role in educating students and young researchers.
Download or read book Refractory Castable Engineering written by Ana Paula da Luz and published by . This book was released on 2015 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interfacial Transport Phenomena written by John C. Slattery and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 1174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport phenomena is used here to descril>e momentum, energy, mass, and entropy transfer (Bird et al. 1960, 1980). It includes thermodynamies, a special case of which is thermostatics. Interfacial transport phenomena refers to momentum, energy , mass, and entropy transfer within the immediate neighborhood of a phase interface, including the thermodynamies of the interface. In terms of qualitative physical observations, this is a very old field. Pliny the EIder (Gaius Plinius Secundus, 23-79 A.D.; Pliny 1938) described divers who released small quantities of oil from their mouths, in order to damp capillary ripples on the ocean surface and in this way provide more uniform lighting for their work. Similar stories were retold by Benjamin Franklin, who conducted experiments of his own in England (V an Doren 1938). In terms of analysis, this is a generally young field. Surface thermostatics developed relatively early, starting with Gibbs (1948) and continuing with important contributions by many others (see Chapter 5).
Download or read book Metal Oxide Nanoparticles 2 Volume Set written by Oliver Diwald and published by John Wiley & Sons. This book was released on 2021-09-14 with total page 903 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxide Nanoparticles A complete nanoparticle resource for chemists and industry professionals Metal oxide nanoparticles are integral to a wide range of natural and technological processes—from mineral transformation to electronics. Additionally, the fields of engineering, electronics, energy technology, and electronics all utilize metal oxide nanoparticle powders. Metal Oxide Nanoparticles: Formation, Functional Properties, and Interfaces presents readers with the most relevant synthesis and formulation approaches for using metal oxide nanoparticles as functional materials. It covers common processing routes and the assessment of physical and chemical particle properties through comprehensive and complementary characterization methods. This book will serve as an introduction to nanoparticle formulation, their interface chemistry and functional properties at the nanoscale. It will also act as an in-depth resource, sharing detailed information on advanced approaches to the physical, chemical, surface, and interface characterization of metal oxide nanoparticle powders and dispersions. Addresses the application of metal oxide nanoparticles and its economic impact Examines particle synthesis, including the principles of selected bottom-up strategies Explores nanoparticle formulation—a selection of processing and application routes Discusses the significance of particle surfaces and interfaces on structure formation, stability and functional materials properties Covers metal oxide nanoparticle characterization at different length scales With this valuable resource, academic researchers, industrial chemists, and PhD students can all gain insight into the synthesis, properties, and applications of metal oxide nanoparticles.
Download or read book Multifunctional Composites written by Phuong Nguyen-Tri and published by MDPI. This book was released on 2021-04-01 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the progress in nanotechnology and associated production methods, composite materials are becoming lighter, cheaper, more durable, and more versatile. At present, great progress has been made in the design, preparation, and characterization of composite materials, making them smarter and versatile. By creating new properties using suitable fillers and matrix, functional composites can meet the most challenging standards of users, especially in high-tech industries. Advanced composites reinforced by high-performance carbon fibers and nanofillers are popular in the automotive and aerospace industries thanks to their significant advantages, such as high specific strength to weight ratio and noncorrosion properties. In addition to the improvement of the mechanical performance, composite materials today are designed to provide new functions dealing with antibacterial, self-cleaning, self-healing, super-hard, and solar reflective properties for desired end-use applications. On the other hand, composite materials can contribute to mitigating environmental issues by providing renewable energy technologies in conjunction with multifunctional, lightweight energy storage systems with high performance and noncorrosive properties. They are also used to prepare a new generation of batteries and directly contribute to H2 production or CO2 reduction in fuels and chemicals. This Special Issue aims to collect articles reporting on recent developments dealing with preparative methods, design, properties, structure, and characterization methods as well as promising applications of multifunctional composites. It covers potential applications in various areas, such as anticorrosion, photocatalyst, absorbers, superhydrophobic, self-cleaning, antifouling/antibacterial, renewable energy, energy storage systems, construction, and electronics. The modeling and simulation of processes involving the design and preparation of functional and multifunctional composites as well as experimental studies involving these composites are all covered in this Special Issue.
