Download or read book Crystal Plasticity at Micro and Nano scale Dimensions written by Ronald W. Armstrong and published by MDPI. This book was released on 2021-08-31 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present collection of articles focuses on the mechanical strength properties at micro- and nanoscale dimensions of body-centered cubic, face-centered cubic and hexagonal close-packed crystal structures. The advent of micro-pillar test specimens is shown to provide a new dimensional scale for the investigation of crystal deformation properties. The ultra-small dimensional scale at which these properties are measured is shown to approach the atomic-scale level at which model dislocation mechanics descriptions of crystal slip and deformation twinning behaviors are proposed to be operative, including the achievement of atomic force microscopic measurements of dislocation pile-up interactions with crystal grain boundaries or with hard surface coatings. A special advantage of engineering designs made at such small crystal and polycrystalline dimensions is the achievement of an approximate order-of-magnitude increase in mechanical strength levels. Reasonable extrapolation of macro-scale continuum mechanics descriptions of crystal strength properties at micro- to nano-indentation hardness measurements are demonstrated, in addition to reports on persistent slip band observations and fatigue cracking behaviors. High-entropy alloy, superalloy and energetic crystal properties are reported along with descriptions of deformation rate sensitivities, grain boundary structures, nano-cutting, void nucleation/growth micromechanics and micro-composite electrical properties.

Download or read book Crystal Plasticity at Micro and Nano scale Dimensions written by Ronald W. Armstrong and published by . This book was released on 2021 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present collection of articles focuses on the mechanical strength properties at micro- and nanoscale dimensions of body-centered cubic, face-centered cubic and hexagonal close-packed crystal structures. The advent of micro-pillar test specimens is shown to provide a new dimensional scale for the investigation of crystal deformation properties. The ultra-small dimensional scale at which these properties are measured is shown to approach the atomic-scale level at which model dislocation mechanics descriptions of crystal slip and deformation twinning behaviors are proposed to be operative, including the achievement of atomic force microscopic measurements of dislocation pile-up interactions with crystal grain boundaries or with hard surface coatings. A special advantage of engineering designs made at such small crystal and polycrystalline dimensions is the achievement of an approximate order-of-magnitude increase in mechanical strength levels. Reasonable extrapolation of macro-scale continuum mechanics descriptions of crystal strength properties at micro- to nano-indentation hardness measurements are demonstrated, in addition to reports on persistent slip band observations and fatigue cracking behaviors. High-entropy alloy, superalloy and energetic crystal properties are reported along with descriptions of deformation rate sensitivities, grain boundary structures, nano-cutting, void nucleation/growth micromechanics and micro-composite electrical properties.

Download or read book Enhanced Gradient Crystal plasticity Study of Size Effects in B C C Metal written by Murat Demiral and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Owing to continuous miniaturization, many modern high-technology applications such as medical and optical devices, thermal barrier coatings, electronics, micro- and nano-electro mechanical systems (MEMS and NEMS), gems industry and semiconductors increasingly use components with sizes down to a few micrometers and even smaller. Understanding their deformation mechanisms and assessing their mechanical performance help to achieve new insights or design new material systems with superior properties through controlled microstructure at the appropriate scales. However, a fundamental understanding of mechanical response in surface-dominated structures, different than their bulk behaviours, is still elusive. In this thesis, the size effect in a single-crystal Ti alloy (Ti15V3Cr3Al3Sn) is investigated. To achieve this, nanoindentation and micropillar (with a square cross-section) compression tests were carried out in collaboration with Swiss Federal Laboratories for Materials Testing and Research (EMPA), Switzerland. Three-dimensional finite element models of compression and indentation with an implicit time-integration scheme incorporating a strain-gradient crystal-plasticity (SGCP) theory were developed to accurately represent deformation of the studied body-centered cubic metallic material. An appropriate hardening model was implemented to account for strain-hardening of the active slip systems, determined experimentally. The optimized set of parameters characterizing the deformation behaviour of Ti alloy was obtained based on a direct comparison of simulations and the experiments. An enhanced model based on the SGCP theory (EMSGCP), accounting for an initial microstructure of samples in terms of different types of dislocations (statistically stored and geometrically necessary dislocations), was suggested and used in the numerical analysis. This meso-scale continuum theory bridges the gap between the discrete-dislocation dynamics theory, where simulations are performed at strain rates several orders of magnitude higher than those in experiments, and the classical continuum-plasticity theory, which cannot explain the dependence of mechanical response on a specimen s size since there is no length scale in its constitutive description. A case study was performed using a cylindrical pillar to examine, on the one hand, accuracy of the proposed EMSGCP theory and, on the other hand, its universality for different pillar geometries. An extensive numerical study of the size effect in micron-size pillars was also implemented. On the other hand, an anisotropic character of surface topographies around indents along different crystallographic orientations of single crystals obtained in numerical simulations was compared to experimental findings. The size effect in nano-indentation was studied numerically. The differences in the observed hardness values for various indenter types were investigated using the developed EMSGCP theory.

Download or read book Crystal Plasticity Finite Element Methods written by Franz Roters and published by John Wiley & Sons. This book was released on 2011-08-04 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by the leading experts in computational materials science, this handy reference concisely reviews the most important aspects of plasticity modeling: constitutive laws, phase transformations, texture methods, continuum approaches and damage mechanisms. As a result, it provides the knowledge needed to avoid failures in critical systems udner mechanical load. With its various application examples to micro- and macrostructure mechanics, this is an invaluable resource for mechanical engineers as well as for researchers wanting to improve on this method and extend its outreach.

Download or read book Mechanics and Physics of Solids at Micro and Nano Scales written by Ioan R. Ionescu and published by John Wiley & Sons. This book was released on 2020-02-26 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chronicling the 11th US–France Mechanics and physics of solids at macro- and nano-scales symposium, organized by ICACM (International Center for Applied Computational Mechanics) in Paris, June 2018, this book addresses the breadth of issues raised. It covers a comprehensive range of scientific and technological topics (from elementary plastic events in metals and materials in harsh environments to bio-engineered and bio-mimicking materials), offering a representative perspective on state-of-the-art research and materials. Expounding on the issues related to mesoscale modeling, the first part of the book addresses the representation of plastic deformation at both extremes of the scale – between nano- and macro- levels. The second half of the book examines the mechanics and physics of soft materials, polymers and materials made from fibers or molecular networks.

Download or read book Engineering Plasticity and Its Applications from Nanoscale to Macroscale written by Hoon Huh and published by World Scientific. This book was released on 2009 with total page 925 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of the Asia-Pacific Conference on Engineering Plasticity and Its Applications (AEPA) is to provide a free forum for exchanging ideas and introducing the latest research findings in the field of engineering plasticity. This conference is unique among the related conferences in that it provides a forum for all fields of plasticity so that multi-disciplinary research works are encouraged. This proceedings volume consists of papers presented at AEPA2008, and covers the following categories in all fields of engineering plasticity: constitutive modeling; damage, fracture, fatigue and failure; dynamic loading and crash dynamics; engineering applications and case studies; experimental and numerical techniques; molecular dynamics; nano, meso, micro and crystal plasticity; phase transformations; plastic instability and strain localization; plasticity in advanced materials; plasticity in materials processing technology; plasticity in tribology; porous, cellular and composite materials; structural plasticity; superplasticity; and time-dependent deformation. Ranging from nanoscale to macroscale applications of engineering plasticity, this book touches upon fields as diverse as mechanical engineering, materials science, physics, chemistry and civil engineering.

Download or read book Probing Crystal Plasticity at the Nanoscales written by Arief Budiman and published by . This book was released on 2015-01-31 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Nano Micro Interface 2 Volumes written by Marcel Van de Voorde and published by John Wiley & Sons. This book was released on 2015-03-09 with total page 771 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlling the properties of materials by modifying their composition and by manipulating the arrangement of atoms and molecules is a dream that can be achieved by nanotechnology. As one of the fastest developing and innovative -- as well as well-funded -- fields in science, nanotechnology has already significantly changed the research landscape in chemistry, materials science, and physics, with numerous applications in consumer products, such as sunscreens and water-repellent clothes. It is also thanks to this multidisciplinary field that flat panel displays, highly efficient solar cells, and new biological imaging techniques have become reality. This second, enlarged edition has been fully updated to address the rapid progress made within this field in recent years. Internationally recognized experts provide comprehensive, first-hand information, resulting in an overview of the entire nano-micro world. In so doing, they cover aspects of funding and commercialization, the manufacture and future applications of nanomaterials, the fundamentals of nanostructures leading to macroscale objects as well as the ongoing miniaturization toward the nanoscale domain. Along the way, the authors explain the effects occurring at the nanoscale and the nanotechnological characterization techniques. An additional topic on the role of nanotechnology in energy and mobility covers the challenge of developing materials and devices, such as electrodes and membrane materials for fuel cells and catalysts for sustainable transportation. Also new to this edition are the latest figures for funding, investments, and commercialization prospects, as well as recent research programs and organizations.

Download or read book Mechanics of Advanced Materials written by Vadim V. Silberschmidt and published by Springer. This book was released on 2015-04-09 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents interesting examples of recent developments in this area. Among the studied materials are bulk metallic glasses, metamaterials, special composites, piezoelectric smart structures, nonwovens, etc. The last decades have seen a large extension of types of materials employed in various applications. In many cases these materials demonstrate mechanical properties and performance that vary significantly from those of their traditional counterparts. Such uniqueness is sought – or even specially manufactured – to meet increased requirements on modern components and structures related to their specific use. As a result, mechanical behaviors of these materials under different loading and environmental conditions are outside the boundaries of traditional mechanics of materials, presupposing development of new characterization techniques, theoretical descriptions and numerical tools. The book presents interesting examples of recent developments in this area. Among the studied materials are bulk metallic glasses, metamaterials, special composites, piezoelectric smart structures, nonwovens, etc.

Download or read book The Investigation of Plastic Behavior by Discrete Dislocation Dynamics for Single Crystal Pillar at Submicron Scale written by Yinan Cui and published by Springer. This book was released on 2016-10-26 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis transports you to a wonderful and fascinating small-scale world and tells you the origin of several new phenomena. The investigative tool is the improved discrete dislocation-based multi-scale approaches, bridging the continuum modeling and atomistic simulation. Mechanism-based theoretical models are put forward to conveniently predict the mechanical responses and defect evolution. The findings presented in this thesis yield valuable new guidelines for microdevice design, reliability analysis and defect tuning.

Download or read book Size Effects in Plasticity written by George Voyiadjis and published by Academic Press. This book was released on 2019-08-01 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Size Effects in Plasticity: From Macro to Nano provides concise explanations of all available methods in this area, from atomistic simulation, to non-local continuum models to capture size effects. It then compares their applicability to a wide range of research scenarios. This essential guide addresses basic principles, numerical issues and computation, applications and provides code which readers can use in their own modeling projects. Researchers in the fields of computational mechanics, materials science and engineering will find this to be an ideal resource when they address the size effects observed in deformation mechanisms and strengths of various materials. Provides a comprehensive reference on the field of size effects and a review of mechanics of materials research in all scales Explains all major methods of size effects simulation, including non-local continuum models, non-local crystal plasticity, discrete dislocation methods and molecular dynamics Includes source codes that readers can use in their own projects

Download or read book Principles of Extreme Mechanics XM in Design for Reliability DfR written by Arief Suriadi Budiman and published by Springer Nature. This book was released on 2021-11-13 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses issues pertinent to mechanics and stress generation, especially in recent advanced cases of technology developments, spanning from micrometer interconnects in solar photovoltaics (PV), next-gen energy storage devices to multilayers of nano-scale composites enabling novel stretchable/flexible conductor technologies. In these cases, the mechanics of materials have been pushed to the extreme edges of human knowledge to enable cutting-edge, unprecedented functionalities and technological innovations. Synchrotron X-ray diffraction, in situ small-scale mechanical testing combined with physics-based computational modeling/simulation, has been widely used approaches to probe these mechanics of the materials at their extreme limits due to their recently discovered distinct advantages. The techniques discussed in this manuscript are highlights specially curated from the broad body of work recently reported in the literature, especially ones that the author had led the pursuits at the frontier himself. Extreme stress generation in these advanced material leads to often new failure modes, and hence, the reliability of the final product is directly affected. From the recent topics and various advanced case studies covered in this book, the reader gets an updated knowledge of how new mechanics can and has been applied in Design-for-Reliability (DfR) for some of the latest technological innovations known in our modern world. Further, this also helps in building better designs, which may avoid the pitfalls of the current practiced trends.

Download or read book Crystal Dislocations Their Impact on Physical Properties of Crystals written by Peter Lagerlof and published by MDPI. This book was released on 2019-01-09 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Crystal Dislocations: Their Impact on Physical Properties of Crystals" that was published in Crystals

Download or read book The Plasticity of Metals at the Sub micrometer Scale and Dislocation Dynamics in a Thin Film written by Seok Woo Lee and published by Stanford University. This book was released on 2011 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology has played a significant role in the development of useful engineering devices and in the synthesis of new classes of materials. For the reliable design of devices and for structural applications of materials with micro- or nano-sized features, nanotechnology has always called for an understanding of the mechanical properties of materials at small length scales. Thus, it becomes important to develop new experimental techniques to allow reliable mechanical testing at small scales. At the same time, the development of computational techniques is necessary to interpret the experimentally observed phenomena. Currently, microcompression testing of micropillars, which are fabricated by focused-ion beam (FIB) milling, is one of the most popular experimental methods for measuring the mechanical properties at the micrometer scale. Also, dislocation dynamics codes have been extensively developed to study the local evolution of dislocation structures. Therefore, we conducted both experimental and theoretical studies that shed new light on the factors that control the strength and plasticity of crystalline materials at the sub-micrometer scale. In the experimental work, we produced gold nanopillars by focused-ion beam milling, and conducted microcompression tests to obtain the stress-strain curves. Firstly, the size effects on the strength of gold nanopillars were studied, and "Smaller is Stronger" was observed. Secondly, we tried to change the dislocation densities to control the strength of gold nanopillars by prestraining and annealing. The results showed that prestraining dramatically reduces the flow strength of nanopillars while annealing restores the strength to the pristine levels. Transmission electron microscopy (TEM) revealed that the high dislocation density (~1015 m-2) of prestrained nanopillars significantly decreased after heavy plastic deformation. In order to interpret this TEM observation, potential dislocation source structures were geometrically analyzed. We found that the insertion of jogged dislocations before relaxation or enabling cross-slip during plastic flow are prerequisites for the formation of potentially strong natural pinning points and single arm dislocation sources. At the sub-micron scale, these conditions are most likely absent, and we argue that mobile dislocation starvation would occur naturally in the course of plastic flow. Two more outstanding issues have also been studied in this dissertation. The first involves the effects of FIB milling on the mechanical properties. Since micropillars are made by FIB milling, the damage layer at the free surface is always formed and would be expected to affect the mechanical properties at a sub-micron scale. Thus, pristine gold microparticles were produced by a solid-state dewetting technique, and the effects of FIB milling on both pristine and prestrained microparticles were examined via microcompression testing. These experiments revealed that FIB milling significantly reduces the strength of pristine microparticles, but does not alter that of prestrained microparticles. Thus, we confirmed that if there are pre-existing mobile-dislocations present in the crystal, FIB milling does not affect the mechanical properties. The second issue is the scaling law commonly used to describe the strength of micropillars as a function of sample size. For the scaling law, the power-law approximation has been widely used without understanding fundamental physics in it. Thus, we tried to analyze the power-law approximation in a quantitative manner with the well-known single arm source model. Material parameters, such as the friction stress, the anisotropic shear modulus, the magnitude of Burgers vector and the dislocation density, were explored to understand their effects on the scaling behavior. Considering these effects allows one to rationalize the observed material-dependent power-law exponents quantitatively. In another part of the dissertation, a computational study of dislocation dynamics in a free-standing thin film is described. We improved the ParaDiS (Parallel Dislocation Simulator) code, which was originally developed at the Lawrence Livermore National Laboratory, to deal with the free surface of a free-standing thin film. The spectral method was implemented to calculate the image stress field in a thin film. The faster convergence in the image stress calculation were obtained by employing Yoffe's image stress, which removes the singularity of the traction at the intersecting point between a threading dislocation and free surface. Using this newly developed code, we studied the stability of dislocation junctions and jogs, which are the potential dislocation sources, in a free standing thin film of a face-centered-cubic metal and discussed the creation of a dislocation source in a thin film. In summary, we have performed both microcompression tests and dislocation dynamics simulations to understand the dislocation mechanisms at the sub-micron scale and the related mechanical properties of metals. We believe that these experimental and computational studies have contributed to the enhancement of our fundamental knowledge of the plasticity of metals at the sub-micron scale.

Download or read book Physical Properties of Nanorods written by Roman Krahne and published by Springer Science & Business Media. This book was released on 2013-06-12 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Inorganic nanoparticles are among the most investigated objects nowadays, both in fundamental science and in various technical applications. In this book the physical properties of nanowires formed by nanoparticles with elongated shape, i.e. rod-like or wire-like, are described. The transition in the physical properties is analyzed for nanorods and nanowires consisting of spherical and rod-like nanoparticles. The physical properties of nanowires and elongated inorganic nanoparticles are reviewed too. The optical, electrical, magnetic, mechanical and catalytic properties of nanowires consisting of semiconductors, noble and various other metals, metal oxides properties and metal alloys are presented. The applications of nanorods and nanowires are discussed in the book.

Download or read book Research Methodology on Interfaces of Physics and Chemistry in Micro and Nanoscale Materials written by Nekane Guarrotxena and published by CRC Press. This book was released on 2014-08-04 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers a selection of recent research studies and new developments in physics and chemistry in micro and nanoscale materials. It brings together research contributions from eminent experts in the field from both academic and industry, providing the latest developments in advanced materials chemical domains.

Download or read book Handbook of Micromechanics and Nanomechanics written by Shaofan Li and published by CRC Press. This book was released on 2016-04-19 with total page 1256 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest developments and applications of micromechanics and nanomechanics. It particularly focuses on some recent applications and impact areas of micromechanics and nanomechanics that have not been discussed in traditional micromechanics and nanomechanics books on metamaterials, micromechanics of ferroelectric/piezoelectric,