Ordered Intermetallics


Book Description

Ordered intermetallics constitute a unique class of metallic materials which may be developed as new-generation materials for structural use at high temperatures in hostile environments. At present, there is a worldwide interest in intermetallics, and extensive efforts have been devoted to intermetallic research and development in the U.S., Japan, European countries, and other nations. As a result, significant advances have been made in all areas of intermetallic research. This NATO Advanced Workshop on ordered intermetallics (1) reviews the recent progress, and (2) assesses the future direction of intermetallic research in the areas of electronic structure and phase stability, deformation and fracture, and high-temperature properties. The book is divided into six parts: (1) Electronic Structure and Phase Stability; (2) Deformation and Dislocation Structures; (3) Ductility and Fracture; (4) Kinetic Processes and Creep Behavior; (5) Research Programs and Highlights; and (6) Assessment of Current Research and Recommendation for Future Work. The first four parts review the recent advances in the three focus areas. The fifth part provides highlights of the intermetallic research under major programs and in different institutes and countries. The last part provides a forum for the discussion of research areas for future studies.




High Temperature Aluminides and Intermetallics


Book Description

This volume of proceedings is concerned with an increasingly important area, that of intermetallics and high temperature aluminides, which has recently been attracting a great deal of attention. Nearly 150 papers presented at the meeting held in San Diego in September 1991 are reproduced here. They cover a wide range of related topics such as the bonding characteristic and alloying behaviour of TiA1 intermetallic compounds and the cleavage fracture of ordered intermetallic alloys. All the papers have been reviewed according to the standards set by Materials Science and Engineering. This book will be of interest to metallurgists and materials scientists working with composites who are interested in the latest developments in this fast–moving field.




Physics Of Creep And Creep-Resistant Alloys


Book Description

Unique in its approach, this introduction to the physics of creep concentrates on the physical principles underlying observed phenomena. As such it provides a resource for graduate students in materials science, metallurgy, mechanical engineering, physics and chemistry as well as researchers in other fields. Following a brief mathematical treatment, the authors introduce creep phenomena together with some empirical laws and observations. The mechanisms of creep and diffusion under varying experimental conditions are subsequently analysed and developed. The second half of the text considers alloying in greater detail as well as exploring the structure and properties of superalloys and stress effects in these materials.




High-Temperature Ordered Intermetallic Alloys IV: Volume 213


Book Description

The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.




Structural Intermetallics and Intermetallic Matrix Composites


Book Description

Fills a Prominent Gap in a Significant Area of IntermetallicsPresenting a comprehensive overview of structural intermetallics (the most important class of intermetallics), Structural Intermetallics and Intermetallic Matrix Composites is a reference written with the beginning student as well as the practicing professional in mind. Utilizing the auth




Gamma Titanium Aluminide Alloys


Book Description

The first book entirely dedicated to the topic emphasizes the relation between basic research and actual processing technologies. As such, it covers complex microstructures down to the nanometer scale, structure/property relationships and potential applications in key industries. From the contents: * Constitution * Thermophysical Constants * Phase Transformations and Microstructures * Deformation Behaviour * Strengthening Mechanisms * Creep * Fracture Behaviour * Fatigue * Oxidation Resistance and Related Issues * Alloy Design * Ingot Production and Component Casting * Powder Metallurgy * Wrought Processing * Joining * Surface Hardening * Applications and Component Assessment




Thermally Activated Mechanisms in Crystal Plasticity


Book Description

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.




Emerging Engineering Materials


Book Description

From the Author's Preface The rapid advances in Materials Science and Engineering . . . have convinced many that the design, production and use of advanced materials will shape future manufacturing industries. Competitive advantage within entire industries is shaped by the quality of the materials available to the manufacturers; the early availability of a new material can be leveraged manyfold. In addition, advanced materials or advanced materials processing can signal the birth or death of entire industries, and access to higher quality and lower cost material has permitted some countries to obtain market dominance in several key industries. Much of the new strategy entails harnessing the potential of innovative technology, that is, going back to the nano and molecular states of materials and new, effective ways to create, process, and eventually use them. Rather than being concerned with a relatively small number of generic materials, each possessing a broad range of uses, the materials sector is increasingly concerned with tailoring a growing list of ever more specialized materials for narrow niche applications. New products with better growth prospects such as high-performance alloys, composites, laminates, and a variety of coatings have been emphasized. Materials firms also have sought ways to overcome the weaknesses of ceramics and fully exploit their formidable strengths. "Functional materials" that do more than support structures have been developed for use in sophisticated electronic, optical, magnetic, and biotech applications. This book will . . . show what materials will be available in the next decade or two, in addition to those currently available and their effect on material design, start-up, and production processes.




Microstructure And Properties Of Materials, Vol 2


Book Description

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.




Physical Metallurgy and processing of Intermetallic Compounds


Book Description

The attractive physical and mechanical properties of ordered intermetallic alloys have been recognized since early in this century. However, periodic attempts to develop intermetallics for structural applications were unsuc cessful, due in major part to the twin handicaps of inadequate low-temper ature ductility or toughness, together with poor elevated-temperature creep strength. The discovery, in 1979, by Aoki and Izumi in Japan that small additions of boron caused a dramatic improvement in the ductility of Ni3Al was a major factor in launching a new wave of fundamental and applied research on intermetallics. Another important factor was the issuance in 1984 of a National Materials Advisory Board reported entitled "Structural Uses for Ductile Ordered Alloys," which identified numerous potential defense-related applications and proposed the launching of a coordinated development program to gather engineering property and processing data. A substantial research effort on titanium aluminides was already underway at the Air Force Materials Laboratory at Wright Patterson Air Force Base in Ohio and, with Air Force support, at several industrial and university laboratories. Smaller programs also were under way at Oak Ridge National Laboratory, under Department of Energy sponsorship. These research efforts were soon augmented in the United States by funding from Department of Defense agencies such as Office of Naval Research and Air Force Office of Scientific Research, and by the National Science Foundation.