Download or read book Thermal Stability and Deformation of Nanocrystalline Nickel written by James Edward Darnbrough and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Stability and Deformation of Nanocrystalline Nickel written by James Edward Darnbrough and published by . This book was released on 2014 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Stability of Nanocrystalline Nickel Electrodeposited from an Additive free Electrolyte written by Charles Soong and published by . This book was released on 2009 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thermal stability of nanocrystalline materials has been studied extensively in recent years for a wide spectrum of materials. Specifically, electrodeposited nanocrystalline nickels has shown dramatic sensitivity in its growth behaviour to sulphur impurity concentrations in the range of hundred parts per million. In the current study, a novel approach to eleetrodeposition utilizing strong mechanical agitation and unusually high pulse deposition current densities was developed to produce nanocrystalline nickel with low sulphur content from an additive-free electrolyte. Inductively coupled plasma analysis showed that the sulphur impurity content was less than 10 ppm. Isothermal heat treatments of this material at three annealing temperatures of 285°C, 350°C and 450°C showed no strong evidence of abnormal grain growth, a growth form observed in many past studies on sulphur-containing nanocrystalline nickel. The microstructure evolution was classified via the introduction of log-time distribution histograms, and cumulative volume fraction diagrams. The activation energy and kinetics for grain growth was determined.

Download or read book Transmission Electron Microscopy written by C. Barry Carter and published by Springer. This book was released on 2016-08-24 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text is a companion volume to Transmission Electron Microscopy: A Textbook for Materials Science by Williams and Carter. The aim is to extend the discussion of certain topics that are either rapidly changing at this time or that would benefit from more detailed discussion than space allowed in the primary text. World-renowned researchers have contributed chapters in their area of expertise, and the editors have carefully prepared these chapters to provide a uniform tone and treatment for this exciting material. The book features an unparalleled collection of color figures showcasing the quality and variety of chemical data that can be obtained from today’s instruments, as well as key pitfalls to avoid. As with the previous TEM text, each chapter contains two sets of questions, one for self assessment and a second more suitable for homework assignments. Throughout the book, the style follows that of Williams & Carter even when the subject matter becomes challenging—the aim is always to make the topic understandable by first-year graduate students and others who are working in the field of Materials Science Topics covered include sources, in-situ experiments, electron diffraction, Digital Micrograph, waves and holography, focal-series reconstruction and direct methods, STEM and tomography, energy-filtered TEM (EFTEM) imaging, and spectrum imaging. The range and depth of material makes this companion volume essential reading for the budding microscopist and a key reference for practicing researchers using these and related techniques.

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 Nanostructure formation and thermal stability of Cu and Cu based alloys written by Mohsen Samadi Khoshkhoo and published by Cuvillier Verlag. This book was released on 2015-01-12 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructured materials are materials with grain size smaller than 100 nm. Due to the very small grain size, a large fraction of atoms belong to the grain-boundaries. As a result, their properties are significantly different compared to their coarse-grained counterparts. Generally, a considerable improvement in the properties is observed when the size is reduced to nanometer dimensions. These include high strength and hardness, improved ductility and toughness, as well as enhanced diffusivity, which make this category of materials of particular interest for a wide range of applications. The properties of nanocrystalline materials are strongly affected by their structure and defects density, which in turn are determined by the method of production. As a result, the knowledge of the mechanism of nanostructure formation is a prerequisite for the structure/property optimization.

Download or read book Nanostructured Coatings written by Albano Cavaleiro and published by Springer Science & Business Media. This book was released on 2007-02-19 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book delivers practical insight into a broad range of fields related to hard coatings, from their deposition and characterization up to the hardening and deformation mechanisms allowing the interpretation of results. The text examines relationships between structure/microstructure and mechanical properties from fundamental concepts, through types of coatings, to characterization techniques. The authors explore the search for coatings that can satisfy the criteria for successful implementation in real mechanical applications.

Download or read book Mechanical Properties Microstructure and Thermal Stability of a Nanocrystalline CoCrFeMnNi High entropy Alloy After Severe Plastic Deformation written by and published by . This book was released on 2015 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: An equiatomic CoCrFeMnNi high-entropy alloy (HEA), produced by arc melting and drop casting, was subjected to severe plastic deformation (SPD) using high-pressure torsion. This process induced substantial grain refinement in the coarse-grained casting leading to a grain size of approximately 50 nm. As a result, strength increased significantly to 1950 MPa, and hardness to similar to 520 MV. Analyses using transmission electron microscopy (TEM) and 3-dimensional atom probe tomography (3D-APT) showed that, after SPD, the alloy remained a true single-phase solid solution down to the atomic scale. Subsequent investigations characterized the evolution of mechanical properties and microstructure of this nanocrystalline HEA upon annealing. Isochronal (for 1 h) and isothermal heat treatments were performed followed by microhardness and tensile tests. The isochronal anneals led to a marked hardness increase with a maximum hardness of similar to 630 HV at about 450 degrees C before softening set in at higher temperatures. The isothermal anneals, performed at this peak hardness temperature, revealed an additional hardness rise to a maximum of about 910 MV after 100 h. To clarify this unexpected annealing response, comprehensive microstructural analyses were performed using TEM and 3D-APT. New nano-scale phases were observed to form in the originally single-phase HEA. After times as short as 5 min at 450 degrees C, a NiMn phase and Cr-rich phase formed. With increasing annealing time, their volume fractions increased and a third phase, FeCo, also formed. It appears that the surfeit of grain boundaries in the nanocrystalline HEA offer many fast diffusion pathways and nucleation sites to facilitate this phase decomposition. The hardness increase, especially for the longer annealing times, can be attributed to these nano-scaled phases embedded in the HEA matrix. The present results give new valuable insights into the phase stability of single-phase high-entropy alloys as well as the mechanisms controlling the mechanical properties of nanostructured multiphase composites. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd.

Download or read book Self diffusion and Impurity Diffusion in Pure Metals written by Gerhard Neumann and published by Elsevier. This book was released on 2011-08-19 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diffusion in metals is an important phenomenon, which has many applications, for example in all kinds of steel and aluminum production, and in alloy formation (technical applications e.g. in superconductivity and semiconductor science). In this book the data on diffusion in metals are shown, both in graphs and in equations.Reliable data on diffusion in metals are required by researchers who try to make sense of results from all kinds of metallurgical experiments, and they are equally needed by theorists and computer modelers. The previous compilation dates from 1990, and measurements relying on the electron microprobe and the recent Rutherford backscattering technique were hardly taken into account there.This reference book, containing all results on self-diffusion and impurity diffusion in pure metals with an indication of their reliability, will be useful to everyone in this field for the theory, fundamental research and industrial applications covered.• Up-to-date and complete (including EPMA and RBS investigations)• Indication of reliability of the measurements• Reassessment of many early results• Data can easily be extracted from Tables and Graphs

Download or read book Recrystallization and Related Annealing Phenomena written by F.J. Humphreys and published by Elsevier. This book was released on 2012-12-02 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: The annealing of deformed materials is of both technological importance and scientific interest. The phenomena have been most widely studied in metals, although they occur in all crystalline materials such as the natural deformation of rocks and the processing of technical ceramics. Research is mainly driven by the requirements of industry, and where appropriate, the book discusses the extent to which we are able to formulate quantitative, physically-based models which can be applied to metal-forming processes.The subjects treated in this book are all active research areas, and form a major part of at least four regular international conference series. However, there have only been two monographs published in recent times on the subject of recrystallization, the latest nearly 20 years ago. Since that time, considerable advances have been made, both in our understanding of the subject and in the techniques available to the researcher.The book covers recovery, recrystallization and grain growth in depth including specific chapters on ordered materials, two-phase alloys, annealing textures and annealing during and after hot working. Also contained are treatments of the deformed state and the structure and mobility of grain boundaries, technologically important examples and a chapter on computer simulation and modelling. The book provides a scientific treatment of the subject for researchers or students in Materials Science, Metallurgy and related disciplines, who require a more detailed coverage than is found in textbooks on physical metallurgy, and a more coherent treatment than will be found in the many conference proceedings and review articles.

Download or read book Cold Rolling Texture of Electrodeposited Nanocrystalline FCC Metals written by Yanling Yang and published by American Academic Press. This book was released on 2018-01-16 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Properties of nanocrystalline metals or alloys cannot be predicted according to the phenomena observed in traditional coarse-grained materials. Nanocrystalline materials exhibit special physical and chemical properties, such as extremely high mechanical strength, outstanding thermal, optical, magnetic and electrical properties. Deformation mechanisms of nanocrystalline materials have been discussed for many years. Previous literatures mainly focus on the investigation of deformation behaviors through in-situ experimental methods such as in-situ TEM observation or simulation methods by modeling. With regard to the in-situ TEM observation, it still remains controversial whether the TEM results can represent the deformation behaviors of bulk nanocrystalline materials. In line with the molecular dynamics simulation method, the materials are frequently assumed to be ideal and the strain rate utilized is extraordinarily high. All the above conditions almost cannot be met or validated through experiments. In this work, it is attempted to explore deformation mechanisms of nanocrystalline face-centered cubic metals or alloys based on texture evolution during plastic deformation. Dislocation movements in plastic deformation process are always followed by formation of deformation texture in most cases, and plastic deformation coordinated by grain boundary sliding and/or grain rotation mechanisms does not incur the occurrence of crystallographic texture. Therefore, investigations on texture evolution during plastic deformation are able to provide powerful evidence for the deformation mechanisms of nanocrystalline materials.

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 Thermal Stability Comparison of Nanocrystalline Ni and Co based Materials written by Guillaume Burstert and published by . This book was released on 2004 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Mechanical Properties of Nanocrystalline Materials written by James C. M. Li and published by CRC Press. This book was released on 2011-09-02 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book concentrates on both understanding and development of nanocrystalline materials. The original relation that connects grain size and strength, known as the Hall-Petch relation, is studied in the nanometer grain size region. The breakdown of such a relation is a challenge. Why and how to overcome it? Is the dislocation mechanism still operating when the grain size is very small, approaching the amorphous limit? How do we go from the microstructure information to the continuum description of the mechanical properties?

Download or read book Microjoining and Nanojoining written by Y N Zhou and published by Elsevier. This book was released on 2008-03-27 with total page 835 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many important advances in technology have been associated with nanotechnology and the miniaturization of components, devices and systems. Microjoining has been closely associated with the evolution of microelectronic packaging, but actually covers a much broader area, and is essential for manufacturing many electronic, precision and medical products.Part one reviews the basics of microjoining, including solid-state bonding and fusion microwelding. Part two covers microjoining and nanojoining processes, such as bonding mechanisms and metallurgy, process development and optimization, thermal stresses and distortion, positioning and fixturing, sensing, and numerical modelling. Part three discusses microjoining of materials such as plastics, ceramics, metals and advanced materials such as shape memory alloys and nanomaterials. The book also discusses applications of microjoining such as joining superconductors, the manufacture of medical devices and the sealing of solid oxide fuel cells.This book provides a comprehensive overview of the fundamental aspects of microjoining processes and techniques. It is a valuable reference for production engineers, designers and researchers using or studying microjoining technologies in such industries as microelectronics and biomedical engineering. - Reviews the basics of nanojoining including solid-state bonding and fusion microwelding - Covers microjoining and nanojoining processes such as bonding mechanisms and metallurgy, sensing and numerical modelling - Examines applications of microjoining such as the manufacturing of medical devices, and the sealing of solid oxide fuel cells

Download or read book Nanostructured Materials by High Pressure Severe Plastic Deformation written by Yuntian T. Zhu and published by Springer Science & Business Media. This book was released on 2006-01-20 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, it was reported that nanostructured materials processed under high pressure by HPT and ECAP have an extraordinary combination of both high strength and high ductility, which are two desirable, but rarely co-existing properties. These findings indicate that high-pressure is a critical factor that can be employed to process nanostructured materials with superior mechanical, and possibly also physical, properties. It is the objective of this workshop to review our current knowledge, identify issues for future research, and discuss future directions on the processing and properties of nanostructured materials via SPD techniques, with a special emphasis on high-pressure effects. The 42 peer-reviewed papers in this book cover areas of high pressure effect on the nanostructure and properties of SPD-processed materials, fundamentals of nanostructured materials, development of high-pressure SPD technologies for commercializations, recent advances of SPD technologies as well as applications and future markets of SPD-processed nanostructured materials.