Grain Boundary Effects On Microstructural Stability Of Nanocrystalline Metallic Materials

Download Grain Boundary Effects On Microstructural Stability Of Nanocrystalline Metallic Materials full books in PDF, epub, and Kindle. Read online Grain Boundary Effects On Microstructural Stability Of Nanocrystalline Metallic Materials ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!

Grain Boundary Effects on Microstructural Stability of Nanocrystalline Metallic Materials

Author : Xiaofei Zhu
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (115 download)

DOWNLOAD NOW!

Book Synopsis Grain Boundary Effects on Microstructural Stability of Nanocrystalline Metallic Materials by : Xiaofei Zhu

Download or read book Grain Boundary Effects on Microstructural Stability of Nanocrystalline Metallic Materials written by Xiaofei Zhu and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Grain boundaries play an important role in dictating the mechanical and physical properties of nanocrystalline (NC) materials because of the increased volume fraction of intercrystalline components as the grain size decreases. In general, grain boundaries have a high energy level and there exists a thermodynamic driving force to reduce the overall area of grain boundaries through grain coarsening, making NC material systems intrinsically unstable. Recent investigations also indicate that mechanical deformation can promote grain growth in NC material even at the cryogenic temperatures. In this chapter, first, the current investigation on the grain boundary structures of NC metallic materials is briefly reviewed and then the state-of-the-art of experimental results on the microstructural stability during deformation processes is discussed. Finally, several key issues for improving the microstructure stability of NC metallic materials and possible future work are discussed.

Study of Grain Boundary Character

Author : Tomasz Tański
Publisher : BoD – Books on Demand
ISBN 13 : 9535128612
Total Pages : 186 pages
Book Rating : 4.5/5 (351 download)

DOWNLOAD NOW!

Book Synopsis Study of Grain Boundary Character by : Tomasz Tański

Download or read book Study of Grain Boundary Character written by Tomasz Tański and published by BoD – Books on Demand. This book was released on 2017-01-11 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains eight chapters with original and innovative research studies in the field of grain boundaries. The results presented in the chapters of this book are very interesting and inspiring. This book will be very valuable to all researchers who are interested in the influence of grain boundaries on the structure and different kinds of properties of engineering materials. This book is also addressed to students and professional engineers working in the industry as well as to specialists who pay attention to all aspects related to grain boundaries and their impact on the various properties of innovative materials. The chapters of this book were developed by respected and well-known researchers from different countries.

Understanding the Mechanistic Role of Grain Boundaries on the Strength and Deformation of Nanocrystalline Metals Using Atomistic Simulations

Download Understanding the Mechanistic Role of Grain Boundaries on the Strength and Deformation of Nanocrystalline Metals Using Atomistic Simulations PDF Online Free

Author : Satish Rajaram
Publisher :
ISBN 13 :
Total Pages : 230 pages
Book Rating : 4.:/5 (115 download)

DOWNLOAD NOW!

Book Synopsis Understanding the Mechanistic Role of Grain Boundaries on the Strength and Deformation of Nanocrystalline Metals Using Atomistic Simulations by : Satish Rajaram

Download or read book Understanding the Mechanistic Role of Grain Boundaries on the Strength and Deformation of Nanocrystalline Metals Using Atomistic Simulations written by Satish Rajaram and published by . This book was released on 2019 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystalline (NC) materials, defined structurally by having average grain sizes less than 100nm, exhibit a number of enhanced mechanical properties such as ultrahigh strength, improved wear resistance and greater resistance to fatigue crack initiation compared to coarser grained polycrystalline (PC) materials. NC materials exhibit these improved properties, in part, due to the increased grain boundary (GB) volume fraction. NC materials strength increases with decreasing grain size, known as the Hall-Petch (HP) effect often resulting in a peak strength between 10-20nm. Studies have shown that NC materials strength decreases due to the shift from dislocation-dominant to GB-dominant deformation mechanisms in the plastic flow regime as average grain size decreases below 10-20nm. While the potential improved properties are of interest, the application of NC materials are hindered due to microstructural instability i.e., grain growth to reduce the total energy of the system, thus degrading desired mechanical properties. Numerous studies have looked at avenues to stabilize NC microstructure, namely through thermodynamics and kinetics, alloying has been one significant strategy used to stabilize NC materials. As these processes are used to stabilize NC microstructures to thermally-induce grain growth, they add additional uncertainty as the deformation and GB behavior of pure NC materials are still not fully understood. Experimental work on NC materials is difficult due to the length scale being investigated as it is difficult to manufacture and can be time consuming to analyze with current technology. Atomistic simulations have shown the potential to investigate fundamental behavior at the nanoscale and provide important insight in the mechanisms that drive the mechanical behavior of NC materials. This thesis will use atomistic simulations to study the structure-property relationship of face-centered-cubic (fcc) metals by focusing on GBs to investigate the strength of NC nickel. During the course of this thesis, four aspects that govern NC behavior will be studied, yielding, plasticity, thermal effects, and GB disorder to elucidate deeper insight into the underlying deformation mechanisms that control the strength of FCC NC metals i.e., flow stress, in the grain size regime 6 to 20nm.

Grain Boundary Segregation in Nanocrystructured Metallic Materials

Author : Jinyu Zhang
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (115 download)

DOWNLOAD NOW!

Book Synopsis Grain Boundary Segregation in Nanocrystructured Metallic Materials by : Jinyu Zhang

Download or read book Grain Boundary Segregation in Nanocrystructured Metallic Materials written by Jinyu Zhang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this chapter is to shed light on the effects of grain boundary segregation on microstructural evolution in nanostructured metallic materials as well as on their mechanical properties. Several key topics will be covered. First, a brief explanation of mechanical stress-driven grain growth in nanostructured Al, Ni, and Cu thin films will be provided in terms of a deformation mechanism map. It will become clear that the excess energy of grain boundaries enable the nanostructured metals to suffer from significant microstructure evolution via dislocation-boundary interactions during plastic deformation even at room temperature. Manipulation of grain boundary structures/properties via dopants segregation at grain boundaries to inhibit grain coalescence associated with remarkably enhanced mechanical properties is then discussed in three representative binary Cu-based systems, id est, Cu-Zr, Cu-Al, and Cu-W. This is finally followed by a summary of this chapter.

Transmission Electron Microscopy

Author : C. Barry Carter
Publisher : Springer
ISBN 13 : 3319266519
Total Pages : 543 pages
Book Rating : 4.3/5 (192 download)

DOWNLOAD NOW!

Book Synopsis Transmission Electron Microscopy by : C. Barry Carter

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.

Microstructure And Properties Of Materials, Vol 2

Author : James C M Li
Publisher : World Scientific Publishing Company
ISBN 13 : 9813105658
Total Pages : 454 pages
Book Rating : 4.8/5 (131 download)

DOWNLOAD NOW!

Book Synopsis Microstructure And Properties Of Materials, Vol 2 by : James C M Li

Download or read book Microstructure And Properties Of Materials, Vol 2 written by James C M Li and published by World Scientific Publishing Company. This book was released on 2000-10-09 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second volume of an advanced textbook on microstructure and properties of materials. (The first volume is on aluminum alloys, nickel-based superalloys, metal matrix composites, polymer matrix composites, ceramics matrix composites, inorganic glasses, superconducting materials and magnetic materials). It covers titanium alloys, titanium aluminides, iron aluminides, iron and steels, iron-based bulk amorphous alloys and nanocrystalline materials.There are many elementary materials science textbooks, but one can find very few advanced texts suitable for graduate school courses. The contributors to this volume are experts in the subject, and hence, together with the first volume, it is a good text for graduate microstructure courses. It is a rich source of design ideas and applications, and will provide a good understanding of how microstructure affects the properties of materials.Chapter 1, on titanium alloys, covers production, thermomechanical processing, microstructure, mechanical properties and applications. Chapter 2, on titanium aluminides, discusses phase stability, bulk and defect properties, deformation mechanisms of single phase materials and polysynthetically twinned crystals, and interfacial structures and energies between phases of different compositions. Chapter 3, on iron aluminides, reviews the physical and mechanical metallurgy of Fe3Al and FeAl, the two important structural intermetallics. Chapter 4, on iron and steels, presents methodology, microstructure at various levels, strength, ductility and strengthening, toughness and toughening, environmental cracking and design against fracture for many different kinds of steels. Chapter 5, on bulk amorphous alloys, covers the critical cooling rate and the effect of composition on glass formation and the accompanying mechanical and magnetic properties of the glasses. Chapter 6, on nanocrystalline materials, describes the preparation from vapor, liquid and solid states, microstructure including grain boundaries and their junctions, stability with respect to grain growth, particulate consolidation while maintaining the nanoscale microstructure, physical, chemical, mechanical, electric, magnetic and optical properties and applications in cutting tools, superplasticity, coatings, transformers, magnetic recordings, catalysis and hydrogen storage.

Microstructural Stability of Nanostructured Fcc Metals During Cyclic Deformation and Fatigue

Author : Matthias Friedrich Funk
Publisher : KIT Scientific Publishing
ISBN 13 : 3866449186
Total Pages : 218 pages
Book Rating : 4.8/5 (664 download)

DOWNLOAD NOW!

Book Synopsis Microstructural Stability of Nanostructured Fcc Metals During Cyclic Deformation and Fatigue by : Matthias Friedrich Funk

Download or read book Microstructural Stability of Nanostructured Fcc Metals During Cyclic Deformation and Fatigue written by Matthias Friedrich Funk and published by KIT Scientific Publishing. This book was released on 2014-05-22 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructured metals with maximal grain or twin sizes of less than 100 nm have advanced properties like increased strength.As beneficial as these microstructures can be for the strength of materials, they are not infinitely stable. During mechanical loading these metals tend to coarsen and lose their beneficial structure. Besides electron microscopic analysis of fatigued samples, in situ cycling tests were conducted in order to observe structural degradation during mechanical loading.

Influences of Stress-driven Grain Boundary Motion on Microstructural Evolution in Nanocrystalline Metals

Author : Mohammad Aramfard
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (135 download)

DOWNLOAD NOW!

Book Synopsis Influences of Stress-driven Grain Boundary Motion on Microstructural Evolution in Nanocrystalline Metals by : Mohammad Aramfard

Download or read book Influences of Stress-driven Grain Boundary Motion on Microstructural Evolution in Nanocrystalline Metals written by Mohammad Aramfard and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystalline (NC) metals with averaged grain size smaller than 100 nm have shown promising mechanical properties such as higher hardness and toughness than conventional coarse-grained metals. Unlike conventional metals in which the deformation is controlled by dislocation activities, the microstructural evolution in NC metals is mainly dominated by grain rotation and stress-driven grain boundary motion (SDGBM) due to the high density of grain boundaries (GBs). SDGBM is thus among the most studied modes of microstructural evolution in NC materials with particular interests on their fundamental atomistic mechanisms. In the first part of this thesis, molecular dynamics simulations were used to investigate the influences of Triple Junctions (TJs) on SDGBM of symmetric tilt GBs in copper by considering a honeycomb NC model. TJs exhibited asymmetric pinning effects to the GB migration and the constraints by the TJs and neighboring grains led to remarkable non-linear GB motion in directions both parallel and normal to the applied shear. Based on these findings, a generalized model for SDGBM in NC Cu was proposed. In the second part, the interaction of SDGBM with crack, voids and precipitates was investigated. It was found that depending on the GB structure, material type and temperature, there is a competition between different atomistic mechanisms such as crack healing, recrystallization and GB decohesion. It is hoped that the findings of this work could clarify the micro-mechanisms of various experimental phenomena such as grain refinement in metals during severe plastic deformation, which can be used to design optimized route of making stabilized bulk NC metals.

Grain Boundary Structure and Interfacial Complexions for the Creation of Tough, Stable Nanostructured Metals

Author : Amirhossein Khalajhedayati
Publisher :
ISBN 13 : 9781321996067
Total Pages : 127 pages
Book Rating : 4.9/5 (96 download)

DOWNLOAD NOW!

Book Synopsis Grain Boundary Structure and Interfacial Complexions for the Creation of Tough, Stable Nanostructured Metals by : Amirhossein Khalajhedayati

Download or read book Grain Boundary Structure and Interfacial Complexions for the Creation of Tough, Stable Nanostructured Metals written by Amirhossein Khalajhedayati and published by . This book was released on 2015 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystalline metals have been the focus of current literature due to their interesting mechanical properties. This is a result of having nanometer sized grains and high volume fraction of grain boundaries. While these materials have high strength, the large number of boundaries is also responsible for the limited ductility and thermal instability often observed for nanocrystalline systems. Despite the current efforts in the literature, these challenges still prevent widespread use of nanocrystalline metals in real engineering applications. In this thesis, we study these problems by focusing on tailoring the grain boundary structure and chemistry and propose a methodology that can be used to mitigate those challenges. First, we study the plastic flow and failure as a function of grain boundary volume fraction (i.e., grain size) using microcompression in a nanocrystalline Ni-W. Since grain boundary physics are extremely important here, we also study how the relaxation of nonequilibrium grain boundaries affects failure. We show that nanocrystalline metals with larger grain boundary volume fractions and relaxed boundary structures are stronger, but also more likely to fail prematurely through catastrophic shear banding. We also show that shear banding can create a dynamic microstructure leading to grain coarsening. A major take-away from this work is that disordered grain boundaries can actually be beneficial. Therefore, in the next study we introduce amorphous complexions, highly disordered grain boundaries, through grain boundary doping as an all-in-one solution to design against failure and thermal instability. We use nanocrystalline Cu with the addition of Zr as our model system to explore complexion engineering in these materials. High resolution transmission electron microscopy in conjunction with energy dispersive x-ray spectroscopy demonstrates segregation of Zr to the boundaries of Cu-Zr alloys created with mechanical alloying. This provided evidence for the formation of amorphous grain boundaries complexions under certain conditions. Microcompression and in-situ bending experiments are then used to quantify the effect of doping on mechanical behavior. Finally, our results show that strength, strain-to-failure, failure mode, and thermal stability can be controlled with boundary doping. The proposed methodology described here is rather general and can be applied to other material systems to make bulk nanocrystalline metals with improved mechanical properties.

Grain Boundaries

Author : P. E. J. Flewitt
Publisher : Wiley
ISBN 13 : 9780471979517
Total Pages : 0 pages
Book Rating : 4.9/5 (795 download)

DOWNLOAD NOW!

Book Synopsis Grain Boundaries by : P. E. J. Flewitt

Download or read book Grain Boundaries written by P. E. J. Flewitt and published by Wiley. This book was released on 2001-04-11 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over recent years the understanding of grain boundaries, interphase boundaries and free surfaces has advanced greatly, leading to a clear recognition that these discontinuities make a significant contribution to the physical and mechanical properties of materials from multiphase metals and alloys to electronic materials. Grain Boundaries -Their Microstructure and Chemistry discusses the interrelationship between microstructure and chemistry of the grain boundary, with particular emphasis on the influence of the environment (air, liquid and liquid metal) and composition (bulk and impurity). This highly practical volume presents a brief background to interphase and grain boundaries, before considering in detail grain boundary composition and composition changes, and how grain boundary composition affects material properties. Very recent advances in techniques such as electron energy loss spectroscopy, high-resolution transmission electron microscopy and atom probe, and the facinating new insights into grain boundary, microstructure that they have revealed, are also discussed. Grain Boundaries - Their Microstructure and Chemistry is an indispensable text for design and safety engineers in many industries, including power and aerospace, as well as for materials scientists and engineers in academia and research institutes.

Grain Boundary Segregation in Metals

Author : Pavel Lejcek
Publisher : Springer Science & Business Media
ISBN 13 : 3642125050
Total Pages : 249 pages
Book Rating : 4.6/5 (421 download)

DOWNLOAD NOW!

Book Synopsis Grain Boundary Segregation in Metals by : Pavel Lejcek

Download or read book Grain Boundary Segregation in Metals written by Pavel Lejcek and published by Springer Science & Business Media. This book was released on 2010-07-20 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grain boundaries are important structural components of polycrystalline materials used in the vast majority of technical applications. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities. It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. The current book deals with fundamentals of grain boundary segregation in metallic materials and its relationship to the grain boundary structure, classification and other materials properties.

Nanostructured Metals and Alloys

Author : S H Whang
Publisher : Elsevier
ISBN 13 : 0857091123
Total Pages : 840 pages
Book Rating : 4.8/5 (57 download)

DOWNLOAD NOW!

Book Synopsis Nanostructured Metals and Alloys by : S H Whang

Download or read book Nanostructured Metals and Alloys written by S H Whang and published by Elsevier. This book was released on 2011-03-22 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tensile strength, fatigue strength and ductility are important properties of nanostructured metallic materials, which make them suitable for use in applications where strength or strength-to-weight ratios are important. Nanostructured metals and alloys reviews the latest technologies used for production of these materials, as well as recent advances in research into their structure and mechanical properties. One of the most important issues facing nanostructured metals and alloys is how to produce them. Part one describes the different methods used to process bulk nanostructured metals and alloys, including chapters on severe plastic deformation, mechanical alloying and electrodeposition among others. Part two concentrates on the microstructure and properties of nanostructured metals, with chapters studying deformation structures such as twins, microstructure of ferrous alloys by equal channel angular processing, and characteristic structures of nanostructured metals prepared by plastic deformation. In part three, the mechanical properties of nanostructured metals and alloys are discussed, with chapters on such topics as strengthening mechanisms, nanostructured metals based on molecular dynamics computer simulations, and surface deformation. Part four focuses on existing and developing applications of nanostructured metals and alloys, covering topics such as nanostructured steel for automotives, steel sheet and nanostructured coatings by spraying. With its distinguished editor and international team of contributors, Nanostructured metals and alloys is a standard reference for manufacturers of metal components, as well as those with an academic research interest in metals and materials with enhanced properties.

The Effect of Solutes on Interface Structure and Microstructural Stability in Binary, Nanocrystalline Alloys

Author : Jonathan Priedeman
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

DOWNLOAD NOW!

Book Synopsis The Effect of Solutes on Interface Structure and Microstructural Stability in Binary, Nanocrystalline Alloys by : Jonathan Priedeman

Download or read book The Effect of Solutes on Interface Structure and Microstructural Stability in Binary, Nanocrystalline Alloys written by Jonathan Priedeman and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stabilizing a nanocrystalline material against grain growth is necessary to preserve the nanostructure and associated strength while experiencing conditions experienced during manufacturing and/or service. This work examines the structures and stability provided by solutes in different alloys. First, a platinum-gold alloy thin film is examined during in-situ annealing where observations of a faceted grain boundary structure are made. Atomistic simulations reveal that segregation of gold to that grain boundary stabilize such a structure. Second, a bulk copper-niobium alloy is plastically deformed at elevated temperature. The nanostructure of the alloy is preserved, indicating good stability. The strength of the niobium-doped alloy, however, is more sensitive to temperature than a related copper-tantalum alloy. This sensitivity is found to be a result of the oxidation behavior of the solutes: theoretical calculations of the misfit strengthening provided by these oxide precipitates reveal greater temperature sensitivity than either the niobium or tantalum precipitates. Third, a bulk copper-hafnium alloy is also plastically deformed at elevated temperature, and the nanostructure is also retained. Here the hafnium was processed as a conformal coating over the copper powder prior to consolidation rather than use of an elemental powder-powder mixing. The copper-hafnium alloy has good low-temperature strength, but begins deforming by grain boundary mediated mechanisms at much lower temperatures compared to copper-tantalum and copper-niobium. Again, the precipitates contribute to this behavior, as the hafnium oxidizes to form a monoclinic hafnium dioxide. This oxide provides good resistance to dislocation propagation but does not reinforce grain boundaries due to lack of coherency. Thus, in all three alloys studied, the solute behavior as it seeks to achieve local equilibrium has profound effects on observed structural evolution (and mechanical response).

Quantification of Grain Boundary Mediated Plasticity Mechanisms in Nanocrystalline Metals

Author : Jason F. Panzarino
Publisher :
ISBN 13 : 9781369228304
Total Pages : 147 pages
Book Rating : 4.2/5 (283 download)

DOWNLOAD NOW!

Book Synopsis Quantification of Grain Boundary Mediated Plasticity Mechanisms in Nanocrystalline Metals by : Jason F. Panzarino

Download or read book Quantification of Grain Boundary Mediated Plasticity Mechanisms in Nanocrystalline Metals written by Jason F. Panzarino and published by . This book was released on 2016 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystalline metals have been a topic of great discussion over recent years due to their exceptional strengths and novel grain boundary-mediated deformation mechanisms. Their microstructures are known to evolve through dynamic processes such as grain boundary migration and grain rotation, but how the collective interaction of these mechanisms alter the microstructure on a larger scale is not completely understood. In this thesis, we present coupled atomistic modeling and experimental tasks that aim to understand how the grain structure, grain boundaries, and associated grain boundary network change during nanocrystalline plasticity. Due to the complex three-dimensional nature of these mechanisms and the limited spatial and temporal resolution of current in-situ experimental techniques, we turn to atomistic modeling to help understand the dynamics by which these mechanisms unfold. In order to provide a quantitative analysis of this behavior, we develop a tool which fully characterizes nanocrystalline microstructures in atomistic models and subsequently tracks their evolution during molecular dynamics simulations. We then use this algorithm to quantitatively track grain structure and boundary network evolution in plastically deformed nanocrystalline Al, finding that higher testing temperature and smaller average grain size results in increased evolution of grain structure with evidence of larger scale changes to the grain boundary network also taking place. This prompts us to extend our analysis technique to include full characterization of grain boundary networks and rigorous topographical feature identification. We then employ this tool on simulations of Al subject to monotonic tension, cycling loading, and simple annealing, and find that each case results in different evolution of the grain boundary network. Finally, our computational work is complemented synergistically by experimental analyses which track surface microstructure evolution during sliding wear of nanocrystalline Ni-W thin films. These experiments track the development of a surface grain growth layer which evolves through grain boundary mediated plasticity and we are able to make direct connections between this evolution and that which was observed in our simulation work. All of the findings of this thesis are a direct result of the dynamic and collective nature by which nanocrystalline materials deform.

Variations in Grain Boundary Segregation for Nanocrystalline Stability and Strength

Author : Oscar Figueroa (III.)
Publisher :
ISBN 13 :
Total Pages : 39 pages
Book Rating : 4.:/5 (821 download)

DOWNLOAD NOW!

Book Synopsis Variations in Grain Boundary Segregation for Nanocrystalline Stability and Strength by : Oscar Figueroa (III.)

Download or read book Variations in Grain Boundary Segregation for Nanocrystalline Stability and Strength written by Oscar Figueroa (III.) and published by . This book was released on 2012 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last few decades, nanocrystalline metals have been of increasing interest. Their ability to show increased yield strength and uniform structure show them to be potentially useful in many applications. Additionally, nanocrystalline metals have become more easily manufactured in recent years, allowing for more testing and more use within industrial settings. However, nanocrystalline metals are still highly unstable, mainly due to temperature related growth. Grain boundary segregation is one way in which materials can keep nano length-scale grains. This process involves metal alloys that preferentially segregate the alloying material to the grain boundaries, potentially leading to Grain Boundary Embrittlement (GBE). Using an ideal work of fracture equation, [gamma] = 2[sigma]s - [sigma]g, the energy required to fracture nanocrystalline metal alloys was obtained, and predicted grain stability. Fracture toughness data is also calculated and compared. A contrast between bulk and nanocrystalline alloys is then made, showing benefits to the use of either set of materials for specific alloy functions.

Mechanical Properties of Nanocrystalline Materials

Author : James C. M. Li
Publisher : CRC Press
ISBN 13 : 9814241970
Total Pages : 346 pages
Book Rating : 4.8/5 (142 download)

DOWNLOAD NOW!

Book Synopsis Mechanical Properties of Nanocrystalline Materials by : James C. M. Li

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?

Mechanical Properties and Deformation Behavior of Materials Having Ultra-Fine Microstructures

Author : M. Nastasi
Publisher : Springer Science & Business Media
ISBN 13 : 9401117659
Total Pages : 616 pages
Book Rating : 4.4/5 (11 download)

DOWNLOAD NOW!

Book Synopsis Mechanical Properties and Deformation Behavior of Materials Having Ultra-Fine Microstructures by : M. Nastasi

Download or read book Mechanical Properties and Deformation Behavior of Materials Having Ultra-Fine Microstructures written by M. Nastasi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an attempt to meet the demand for new ultra-high strength materials, the processing of novel material configurations with unique microstructure is being explored in systems which are further and further from equilibrium. One such class of emerging materials is the so-called nanophased or nanostructured materials. This class of materials includes metals and alloys, ceramics, and polymers characterized by controlled ultra-fine microstructural features in the form oflayered, fibrous, or phase and grain distribution. While it is clear that these materials are in an early stage of development, there is now a sufficient body of literature to fuel discussion of how the mechanical properties and deformation behavior can be controlled through control of the microstructure. This NATO-Advanced Study Institute was convened in order to assess our current state of knowledge in the field of mechanical properties and deformation behavior in materials with ultra fine microstructure, to identify opportunities and needs for further research, and to identify the potential for technological applications. The Institute was the first international scientific meeting devoted to a discussion on the mechanical properties and deformation behavior of materials having grain sizes down to a few nanometers. Included in these discussions were the topics of superplasticity, tribology, and the supermodulus effect. Lectures were also presented which covered a variety of other themes including synthesis, characterization, thermodynamic stability, and general physical properties.