Download or read book Deformation Mechanisms of Nanocrystalline Nickel Studied by In situ X ray Diffraction written by Stefan Brandstetter and published by . This book was released on 2009 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Deformation Mechanisms in Nanocrystalline Metals and Alloys by in Situ Synchrotron X ray Diffraction written by Jochen Andreas Lohmiller and published by KIT Scientific Publishing. This book was released on 2014-05-22 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, different nanocrystalline metals and alloys were investigated by a synchrotron-based in situ XRD mechanical testing technique in order to investigate the dominant deformation mechanisms. All tested samples show a succession and coexistence of several mechanisms, regardless of grain size, loading condition, or sample geometry. However, the relative shares of the individual mechanisms strongly vary and depend on parameters such as grain size, sample purity, and alloy composition.
Download or read book Footprints of Deformation Mechanisms During In situ X ray Diffraction written by Zeljka Budrovic and published by . This book was released on 2006 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Footprints of Deformation Mechanisms During In situ X ray Diffraction written by Željka Budrović and published by . This book was released on 2006 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The World Bank written by Katherine Marshall and published by Routledge. This book was released on 2008-01-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The World Bank is one of the most important and least understood major international institutions. This book provides a concise, accessible and comprehensive overview of the World Bank's history, development, structure, functionality and activities. These themes are illustrated with a wide variety of case studies drawn from the Bank's int
Download or read book The Systematic Study of Deformation and Fracture Mechanism of Nano Crystalline Nickel written by Manish Sharma and published by . This book was released on 2020-04-14 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present study is initiated with the specific objective of observing, both during and after deformation in Nickel Crystal by TEM experiments, the mechanisms of the deformation and fracture using state of the art experimental tools in high purity, fully dense nanocrystalline metals with a narrow range of gain sizes. The goal is to develop a strategy to reach the rational design of nanomaterials i.e. nanocrystal Nickel with modelled and controlled particles size, morphology, orientation, and crystal structure, i.e. purpose-built nanomaterials, to probe, tune, and optimize their physical, chemical properties and mechanical properties. In our view, to achieve such ambitious challenge, the most pertinent parameter to monitor is the dislocation mechanism of the system. In an attempt to take part in the fascinating nanoworld, and to contribute to its ambitious challenges, the present review will expose the outcome of a novel general concept of nucleation, growth, thin film processing method. Now a days, new concepts of nanocomposites and nano glasses are also being investigated with special emphasis on ceramic composites to increase their strength and toughness. There appears to be a great potential for applications in the near future for nanocrystalline materials. The extensive investigations in recent years on structure-property correlations in nanocrystalline materials have begun to unravel the complexities of these materials, and pave the way for successful exploitation of alloy design principles to synthesize better materials than hitherto available. For the first time, direct and compelling conclusive evidence of the deformation mechanism crossover is provided. In addition, unexpected dislocation activities are also observed in grains as small as 5 nm. Nano beam diffraction observations revealed that a nanocrystalline grain with a size of about 20 nm may experience ultrahigh elastic strain during deformation and the implication of this finding is discussed in detail. Also Understanding the formation mechanisms and role of grain agglomerates in nanocrystalline metals is expected to directly impact the processing methods required to create nanocrystalline metals with improved strength and ductility.
Download or read book Deformation Study of Nanocrystalline Ni fe Alloy Using Synchroton Diffraction written by Li Li and published by . This book was released on 2010 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation addresses two critical issues in the deformation of nc metals and alloys: (1) A stress-induced genuine grain growth after the plastic deformation rather than just a change of the grain shape; (2) A systematically quantitative study of micrsostructural evolution during the plastic deformation. These two critical issues point to the deformation of nc materials with the average-grain sizes within the range of 10 to 50 nm, which is the most interesting and controversial region in the current time. The current study provides a systematic and detailed microstructural evolution for this region, which is definitely beneficial for the investigation of the deformation mechanism in this region, especially for the simulation. The main experimental and data-analysis methods employed in this research are synchrotron high-energy X-ray diffraction, X-ray line profile analysis, and texture analysis. The combination of these methods is beneficial to the accurate microstructural interpretation of the bulk materials.
Download or read book In Situ TEM Studies of Deformation Mechanisms in Nanoindentation of Ultrafine grained and Nanocrystalline Metals written by Miao Jin and published by . This book was released on 2006 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanical properties of ultrafine-grained and nanocrystalline materials have received a great deal of recent attention because of their unusual and promising values. However, some of the most important mechanisms of deformation remain unclear. To address this issue, an in situ nanoindentation stage has been used in a transmission electron microscope to explore the deformation behaviors of nanocrystalline aluminum, ultrafine-grained aluminum, and ultrafine-grained iron in real time.
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 Study of Deformation Behavior of Nanocrystalline Nickel Using Nanoindentation Techniques written by Changli Wang and published by . This book was released on 2010 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystalline materials with grain size less than 100 nm have been receiving much attention because of their unparallel properties compared with their microcrystalline counterparts. Because of its high hardness, nanocrystalline nickel has been used for MEMS. Long term thermomechnical properties and deformation mechanism at both ambient and elevated temperatures need to be evaluated which is vital for reliability of its applications as structural material. In this thesis, nanoindentation creep of nanocrystalline nickel with an as-deposited grain size of 14 nm was characterized at elevated temperatures. The nanoindentation creep rate was observed to scale with temperature and applied load (or stress), and could be expressed by an empirical power-law equation for describing conventional crystalline solids. Creep activation energy was found to be close to that for grain boundary self-diffusion in nickel. The activation volume was also evaluated using a stress relaxation technique. The creep results were compared with those for fine-grained nickel in the literature. Possible mechanisms were discussed in light of the creep rate and temperature ranges. To provide a direct comparison, uniaxial creep tests were conducted on nanocrystalline nickel with an as-deposited grain size of 14 nm at 398 K. It was found that stress exponents under the two test conditions are almost the same, indicating a similar creep mechanism. However, the strain rate measured by nanoindentation creep was about 100 times faster than that by uniaxial creep. The rate difference was discussed in terms of stress states and the appropriate selection of Tabor factor. To further explore the time-dependent plastic behavior, multiple unload-reload tests were conducted on electrodeposited nanocrystalline nickel in both compression and tension. A hysteresis was observed during each unload-reload cycle, indicating irreversible energy dissipation. The dissipated energy was evaluated and the energy dissipation rate was found to increase with the flow stress to the third power and sensitive to the stress state (tension or compression). A mechanistic model based on grain boundary sliding was proposed to describe the unload-reload behavior. Experimental results were found to be in good agreement with the model predictions, suggesting the observed hysteresis was indeed caused by grain boundary sliding.
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 Nanocrystalline Metals written by Zhen Sun and published by . This book was released on 2016 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mots-clés de l'auteur: nanocrystalline metals and alloys ; in situ X-ray diffraction (XRD) ; stress reduction tests ; molecular dynamics (MD) ; constant deformation resistance.
Download or read book Defects and Deformation in Nanostructured Metals written by Christopher Earl Carlton and published by . This book was released on 2009 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: A better understanding of how the nanoscale environment affects the mechanical properties of materials, in particular metallic nanoparticles and nanocrystalline metals is vital to the development of next generation materials. Of special interest is obtaining a fundamental understanding of the inverse Hall-Petch Effect in nanocrystalline metals, and nanoindentation in individual nanoparticles. Understanding these subjects is critical to understanding how the mechanical properties of materials are fundamentally affected by nanoscale dimensions. These topics have been addressed by a combination of theoretical modeling and in-situ nanoindentation transmission electron microscopy (TEM) analysis. Specifically, the study of the inverse Hall-Petch effect in nanocrystalline metals will be investigated by a thorough review of the literature followed by a proposed novel theoretical model that better explains the experimentally observed behavior of nanocrystalline metals. On the other hand, the nanoindentation of individual nanoparticles is a very new research topic that has yet to aggregate a large body of experimental data. In this context, in-situ TEM nanoindentation experiments on silver nanoparticles will be first performed to determine the mechanisms of deformation in these nanostructures. A theoretical explanation for the observed deformation mechanisms will be then developed and its implications will be discussed. In addition to nanoparticles, this study will also provide unique and valuable insight into the deformation mechanisms of nanopillars, a growing area of research despite much controversy and speculation about their actual mechanisms of deformation. After studying the novel behavior of both nanocrystalline metals and nanoparticles, useful applications of both classes of materials will be explored. The discussion of applications will focus on utilizing the interesting behaviors explored in the dissertation. Of particular interest will be applications of nanoparticles and nanocrystalline materials to coatings, radiation resistance and super-plastic materials.
Download or read book Thermo Mechanically Coupled Cyclic Deformation and Fatigue Failure of NiTi Shape Memory Alloys written by Guozheng Kang and published by Springer Nature. This book was released on 2023-07-24 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by leading experts in the field, this book highlights an authoritative and comprehensive introduction to thermo-mechanically coupled cyclic deformation and fatigue failure of shape memory alloys. The book deals with: (1) experimental observations on the cyclic deformation and fatigue failure in the macroscopic and microscopic scales; (2) molecular dynamics and phase-field simulations for the thermo-mechanical behaviors and underlying mechanisms during cyclic deformation; (3) macroscopic phenomenological and crystal plasticity-based cyclic constitutive models; and (4) fatigue failure models. This book is an important reference for students, practicing engineers and researchers who study shape memory alloys in the areas of mechanical, civil and aerospace engineering as well as materials science.
Download or read book Defect Structure and Properties of Nanomaterials written by J Gubicza and published by Woodhead Publishing. This book was released on 2017-03-05 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: Defect Structure and Properties of Nanomaterials: Second and Extended Edition covers a wide range of nanomaterials including metals, alloys, ceramics, diamond, carbon nanotubes, and their composites. This new edition is fully revised and updated, covering important advances that have taken place in recent years. Nanostructured materials exhibit unique mechanical and physical properties compared with their coarse-grained counterparts, therefore these materials are currently a major focus in materials science. The production methods of nanomaterials affect the lattice defect structure (vacancies, dislocations, disclinations, stacking faults, twins, and grain boundaries) that has a major influence on their mechanical and physical properties. In this book, the production routes of nanomaterials are described in detail, and the relationships between the processing conditions and the resultant defect structure, as well as the defect-related properties (e.g. mechanical behavior, electrical resistance, diffusion, corrosion resistance, thermal stability, hydrogen storage capability, etc.) are reviewed. In particular, new processing methods of nanomaterials are described in the chapter dealing with the manufacturing procedures of nanostructured materials. New chapters on (i) the experimental methods for the study of lattice defects, (ii) the defect structure in nanodisperse particles, and (iii) the influence of lattice defects on electrical, corrosion, and diffusion properties are included, to further enhance what has become a leading reference for engineering, physics, and materials science audiences. - Provides a detailed overview of processing methods, defect structure, and defect-related mechanical and physical properties of nanomaterials - Covers a wide range of nanomaterials including metals, alloys, ceramics, diamond, carbon nanotubes, and their composites - Includes new chapters covering recent advances in both processing techniques and methods for the study of lattice defects - Provides valuable information that will help materials scientists and engineers highlight lattice defects and the related mechanical and physical properties
Download or read book Influence of strain on the functionality of ink jet printed thin films and devices on flexible substrates written by Mishra, Nilesha and published by KIT Scientific Publishing. This book was released on 2019-02-15 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ink-jet printed devices on the flexible substrate are inexpensive and large area compatible as compared to rigid substrates. However, during fabrication and service they are subjected to complex strains, resulting in crack formation or delamination within the layers, affecting the device performance. Therefore, it is necessary to understand their failure mechanisms by correlating their electrical or structural properties with applied strain, supported by detailed microstructural investigations.
Download or read book Microstructures and Mechanical Properties of Nanocrystalline Materials written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
