Download or read book The Influence of High temperature Tensile Deformation on Microstructure Evolution in Select BCC Metals written by Philip James Noell and published by . This book was released on 2015 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-temperature plastic deformation can enhance the rate of grain boundary migration in some metals. In the body-centered-cubic (BCC) refractory metals molybdenum and tantalum, this increased rate of grain boundary migration produces abnormal grain growth at temperatures significantly lower than is possible by static annealing. This phenomenon is termed dynamic abnormal grain growth (DAGG). The influence of microstructure on DAGG is studied by examining the morphology of DAGG grains produced in two Mo sheet materials. DAGG grain propagation in these materials is not uniform throughout the sheet thickness. Variations through the sheet thickness in texture and grain size are explored as causes of these behaviors. DAGG grains in both materials preferentially grow into the finest-grained polycrystalline regions of the sheet. Direct effects of local crystallographic texture variation are not evident in microstructures containing DAGG grains. The initiation of abnormal grains in Mo materials by plastic straining at elevated temperatures is investigated. The minimum strain necessary to initiate DAGG, termed the critical strain, decreases approximately linearly with increasing temperature. The variation in critical strain values observed at a single temperature and strain rate is well described by a normal distribution. An increased fraction of grains aligned with the 110 along the tensile axis, a preferred orientation for DAGG grains, appears to decrease the critical strain for DAGG initiation. Uniaxial tension tests at temperatures between 1650 and 1950 °C were conducted with commercial-purity Mo rods to determine if DAGG can be used to produce large single crystals of Mo. Necking in these tensile rod specimens during the production of DAGG grains presents a potential issue with translation to commercial application. High-temperature tensile tests were also performed on another BCC metal, an interstitial-free steel. Grain growth in this interstitial-free steel during high-temperature plastic deformation is significantly accelerated above that of the static case. Grains generally oriented between {112}110 and {111}113 grow more readily than other grains during dynamic grain growth in this material.
Download or read book High Entropy Alloys written by Michael C. Gao and published by Springer. This book was released on 2016-04-27 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a systematic and comprehensive description of high-entropy alloys (HEAs). The authors summarize key properties of HEAs from the perspective of both fundamental understanding and applications, which are supported by in-depth analyses. The book also contains computational modeling in tackling HEAs, which help elucidate the formation mechanisms and properties of HEAs from various length and time scales.
Download or read book Microstructure Evolution and Its Influence on Deformation Mechanisms During Tensile Creep of DD417G Alloy written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermally Activated Mechanisms in Crystal Plasticity written by D. Caillard and published by Elsevier. This book was released on 2003-09-08 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: KEY FEATURES: - A unified, fundamental and quantitative resource. The result of 5 years of investigation from researchers around the world - New data from a range of new techniques, including synchrotron radiation X-ray topography provide safer and surer methods of identifying deformation mechanisms - Informing the future direction of research in intermediate and high temperature processes by providing original treatment of dislocation climb DESCRIPTION: Thermally Activated Mechanisms in Crystal Plasticity is a unified, quantitative and fundamental resource for material scientists investigating the strength of metallic materials of various structures at extreme temperatures. Crystal plasticity is usually controlled by a limited number of elementary dislocation mechanisms, even in complex structures. Those which determine dislocation mobility and how it changes under the influence of stress and temperature are of key importance for understanding and predicting the strength of materials. The authors describe in a consistent way a variety of thermally activated microscopic mechanisms of dislocation mobility in a range of crystals. The principles of the mechanisms and equations of dislocation motion are revisited and new ones are proposed. These describe mostly friction forces on dislocations such as the lattice resistance to glide or those due to sessile cores, as well as dislocation cross-slip and climb. They are critically assessed by comparison with the best available experimental results of microstructural characterization, in situ straining experiments under an electron or a synchrotron beam, as well as accurate transient mechanical tests such as stress relaxation experiments. Some recent attempts at atomistic modeling of dislocation cores under stress and temperature are also considered since they offer a complementary description of core transformations and associated energy barriers. In addition to offering guidance and assistance for further experimentation, the book indicates new ways to extend the body of data in particular areas such as lattice resistance to glide.
Download or read book Dislocation Dynamics and Plasticity written by Taira Suzuki and published by Springer Science & Business Media. This book was released on 2013-03-07 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the 1950s the direct observation of dislocations became possible, stimulat ing the interest of many research workers in the dynamics of dislocations. This led to major contributions to the understanding of the plasticity of various crys talline materials. During this time the study of metals and alloys of fcc and hcp structures developed remarkably. In particular, the discovery of the so-called in ertial effect caused by the electron and phonon frictional forces greatly influenced the quantitative understanding of the strength of these metallic materials. Statis tical studies of dislocations moving through random arrays of point obstacles played an important role in the above advances. These topics are described in Chaps. 2-4. Metals and alloys with bcc structure have large Peierls forces compared to those with fcc structure. The reasons for the delay in studying substances with bcc structure were mostly difficulties connected with the purification techniques and with microscopic studies of the dislocation core. In the 1970s, these difficulties were largely overcome by developments in experimental techniques and computer physics. Studies of dislocations in ionic and covalent bonding materials with large Peierls forces provided infonnation about the core structures of dislocations and their electronic interactions with charged particles. These are the main subjects in Chaps. 5-7.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metallography and Microstructure in Ancient and Historic Metals written by David A. Scott and published by Getty Publications. This book was released on 1992-01-02 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: David A. Scott provides a detailed introduction to the structure and morphology of ancient and historic metallic materials. Much of the scientific research on this important topic has been inaccessible, scattered throughout the international literature, or unpublished; this volume, although not exhaustive in its coverage, fills an important need by assembling much of this information in a single source. Jointly published by the GCI and the J. Paul Getty Museum, the book deals with many practical matters relating to the mounting, preparation, etching, polishing, and microscopy of metallic samples and includes an account of the way in which phase diagrams can be used to assist in structural interpretation. The text is supplemented by an extensive number of microstructural studies carried out in the laboratory on ancient and historic metals. The student beginning the study of metallic materials and the conservation scientist who wishes to carry out structural studies of metallic objects of art will find this publication quite useful.
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 Austenitic Steels at Low Temperatures written by T. Horiuchi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need for alternate energy sources has led to the develop ment of prototype fusion and MHD reactors. Both possible energy systems in current designs usually require the use of magnetic fields for plasma confinement and concentration. For the creation and maintenance of large 5 to 15 tesla magnetic fields, supercon ducting magnets appear more economical. But the high magnetic fields create large forces, and the complexities of the conceptual reactors create severe space restrictions. The combination of re quirements, plus the desire to keep construction costs at a mini mum, has created a need for stronger structural alloys for service at liquid helium temperature (4 K). The complexity of the required structures requires that these alloys be weldable. Furthermore, since the plasma is influenced by magnetic fields and since magnet ic forces from the use of ferromagnetic materials in many configur ations may be additive, the best structural alloy for most applica tions should be nonmagnetic. These requirements have led to consideration of higher strength austenitic steels. Strength increases at low temperatures are achieved by the addition of nitrogen. The stability of the austenitic structure is retained by adding manganese instead of nickel, which is more expensive. Research to develop these higher strength austenitic steels is in process, primarily in Japan and the United States.
Download or read book Metals Abstracts Index written by and published by . This book was released on 1996 with total page 1634 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics of Solids written by Allan F. Bower and published by CRC Press. This book was released on 2009-10-05 with total page 820 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern computer simulations make stress analysis easy. As they continue to replace classical mathematical methods of analysis, these software programs require users to have a solid understanding of the fundamental principles on which they are based.Develop Intuitive Ability to Identify and Avoid Physically Meaningless PredictionsApplied Mechanics o
Download or read book Proceedings of Crack Paths CP 2012 Gaeta Italy 2012 written by and published by Gruppo Italiano Frattura. This book was released on 2012-09-19 with total page 1170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Hardness of Metals written by David Tabor and published by Oxford University Press. This book was released on 2000-08-03 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is an attempt to explain hardness measurements of metals in terms of some of their more basic physical properties. The intention is to provide, for physicists, engineers, and metallurgists, a better understanding of what hardness means and what hardness measurements imply. The author emphasises the physical concepts involved, so that non-mathematical readers can grasp and appreciate the general physical picture without needing to follow the more detailed mathematical treatment.
Download or read book Metals Abstracts written by and published by . This book was released on 1998 with total page 1076 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ductility and Formability of Metals written by Giovanni Straffelini and published by Elsevier. This book was released on 2023-03-23 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ductility and Formability of Metals: A Metallurgical Engineering Perspective uses metallurgical, mechanical and physical principles and concepts to explain ductility while emphasizing the influence of material microstructure on damage mechanisms. Focusing on steel, aluminum, copper, titanium and magnesium alloys, the book examines the strain hardening behaviors of these metals and alloys, the influence of strain rate and temperature, and ductile fracture mechanics. Hot plastic deformation is covered with special consideration given to its interplay with recrystallization phenomena. Other phenomena such as Dynamic Strain Ageing (DSA) and Adiabatic Shear Banding (ASB) are discussed, and metal working applications such as forging, extrusion and machining are included throughout. Methods for control of ductile cracks in metal parts resulting from rolling, forging, extrusion, drawing, and sheet metal forming are also outlined. Provides an overview on the plastic deformation behavior and ductile fracture of steel, aluminum, copper, titanium and magnesium alloys Illustrates the influence of microstructure on yield behavior, strain hardening of metals, and the influence of strain rate and temperature Covers the role of the strain hardening coefficient (n), strain rate index (m), Dynamic Strain Ageing (DSA), and Adiabatic Shear Banding (ASB) Metalworking applications are provided throughout, including forging, rolling, extrusion, wire drawing, sheet metal forming and machining
Download or read book Titanium Alloys and Titanium Based Matrix Composites written by Maciej Motyka and published by . This book was released on 2021-10-09 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this Special Issue is to present the latest achievements related to the manufacturing and processing of titanium alloys and titanium-based composites. The subjects of published research articles concern deformation behavior, development of microstructure and properties and special applications of titanium-based materials. The Special Issue contains 21 articles-1 editorial, 18 research articles, 1 review and 1 technical note, written by the authors representing scientific institutions from 13 countries. It provides a wide overview of recent research developments on different aspects of titanium-based materials, which should be useful for researchers and engineers working in this field.
Download or read book Bulk Nanostructured Materials written by Ruslan Z. Valiev and published by John Wiley & Sons. This book was released on 2013-09-17 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the most recent results in the area of bulk nanostructured materials and new trends in their severe plastic deformation (SPD) processing, where these techniques are now emerging from the domain of laboratory-scale research into the commercial production of various bulk nanomaterials. Special emphasis is placed on an analysis of the effect of nanostructures in materials fabricated by SPD on mechanical properties (strength and ductility, fatigue strength and life, superplasticity) and functional behavior (shape memory effects, magnetic and electric properties), as well as the numerous examples of their innovative applications. There is a high innovation potential for industrial applications of bulk nanomaterials for structural use (materials with extreme strength) as well as for functional applications such as nanomagnets, materials for hydrogen storage, thermoelectric materials, superconductors, catalysts, and biomedical implants.
