Materials Research and Engineering – serie

Dr. Boris Medovar, a member of the Soviet Academy of Sciences, is a promi­ nent member of the E.O. Paton Electric Welding Institute in Kiev, one of the pre-eminent institutes of the USSR. The Paton Institute, internationally famous for its entrepreneurial efforts in electrical welding processes, is also famous for its application of electrically based processes in melting and remelting of high­ alloy and high-temperature materials. These include the ESR (electroslag re­ melting) process, the ESC (electroslag casting) process, skull remelting based on electron-beam processes, plasma arc processes, and electric arc processes. Along with the ESR process for ingot production is the commercial plasma arc remelt process for specialty steels, particularly where high nitrogen contents may be desired, as in austenitic stainless steels. Major industrial centers are now scattered throughout the USSR and are a major factor in high-alloy, high­ strength, low- and high-temperature materials. The ESR process was developed in response to the Western development of the VAR (vacuum arc remelting) process for producing very highly alloyed materials during the growth period of the jet engine age. The V AR and ESR processes utilize different purification and refinement processes that are extremely critical in very highly, complexly alloyed superalloys and high-speed tool steels. In water-cooled remelt systems, they also achieve relatively rapid (directional) solidification, minimizing segregation and coarse phase separation of undesir­ able impurity elements or elements that tend to form coarse brittle phases.

The purpose of this book is to provide a broad, comprehensive, up-to-date coverage of current beneficiation techniques and processes that are used for both metallic and nonmetallic minerals; and for other materials, such as household and industrial solid wastes, that are also processed by conventional beneficiation methods in their standard methods of recycling and reclamation. Conservation of natural resources is an adjunct of beneficiation in that we have used up once-available deposits of high-grade ores, leaving only the low-grade deposits that must be beneficiated to upgrade them to sufficiently high levels for processing and metal recovery by current extractive technology. Conservation is also important in the reclamation and recycling of indestructible, noncorrosive materials, so that they may be recovered and reused many times over. The mainly physical, relatively uncomplicated, beneficiation treatments also save large quantities of energy, as these comparatively simple operations are all relatively low energy consumers, when compared with the later separation operations of pyro and electrical nature, which are very high energy consumers. Environmentally, both air and water pollution from beneficiation treatments are either quite low or can easily be controlled, and are gas-free and operated at ambient temperature, to make them one of the cleaner and lower polluting processes used in material treatments.

This book seeks to provide a comprehensive coverage of the important and growing field of ladle metallurgy, including theory, practice, and economics. During the past decade, major advances have been made in the secondary metallurgy of steel and other metals; indeed, secondary metallurgy, that is, the ladle treatment of molten metals, following the melting and refining steps, has become an important and inevitable part of the overall processing sequence. Ladle metallurgy is attractive because it can provide an effective means for adjusting and fine-tuning the composition and temperature of the molten products prior to solidification processing. Ladle metallurgy allows us to produce materials of very high purity and will become increasingly an essential process requirement. Indeed, many of the novel casting techniques will mandate steels of much higher cleanliness than those in current practice. Of course, ladle metallurgy or secondary metallurgy is not limited to steel; indeed, major advances have been made and are being made in the secondary processing of aluminum, aluminum alloys, and many specialty metals.

In recent years it has been recognized that tundishes playa critical role in affecting the quality of the finished steel products. Furthermore, proper tundish design may be even more important in the development of the novel continuous casting pro­ cesses that are now in varying stages of realizatic)ll. Traditionally, physical modeling has played a key role in tundish design, but the recently evolved computational software packages, the readily accessible computa­ tional hardware, and, perhaps most important, the growing experience with tackling a broad range of computational fluid flow problems within a metallurgical context have made mathematical modeling an important factor in this field. Our aim in writing this book has been to bring realistic perspectives to tundish design. The main purpose is to provide a good physical understanding of what is happening in tundishes, together with a realistic discussion of topics that are still not quite clear. The process metallurgist active in this field has many tools at his or her disposal, including mathematical modeling, physical modeling, and measure­ ments on full plant-scale systems. In this monograph we seek to show how these ideas may be combined to provide a good basic understanding and, hence, an attempt at an optimal design.

This monograph written by two Chinese scientists of the younger generation opens a window into the world of thoughts on Mechanical Metallurgy in this fascinating area of our world, characterized by age old cultural heritage as weil as by its dynamic evolution into the future. Based on notions and names all so familiar to the western scientist, and regarding the subject from the point of view of the theoretical mechanical engineer (Yang) as weil as that of the materials and manufacturing engineer (Lee), the authors present a synthesis of both approaches and endeavour to guide the reader from basic theory to engineering applications. Between structural defects in the micrometer scale and the meter-measures of engineering components, the term of mesoplasticity is meant to place the reader right in the center: This is certainly achallenging enterprise, and the editor expresses his sincere wishes as to enrichment and stimulation which will emanate from this interesting book and its creative perspective. Prof. B. Ilschner March, 1993. Preface In the past two decades, enormous advances in materials and manufacturing tech­ nology have been achieved, which upgrade the material design, processing and precision manufacturing as quantitative and concise scientific disciplines. Rapid improvements on mechanics understanding have been instrumental in the above­ mentioned development. A topic of great interest and importance in plasticity re­ search has been the design and processing of materials themselves on the mesoscale to achieve the desired macroscopic properties.

Very light, very strong. extremely reliable -aircraft and aerospace engineers are. and have to be. very demanding partners in the materials community. The results of their research and development work is not only crucial for one special area of applications. but can also lead the way to new solutions in many other areas of advanced technology. Springer-Verlag and the undersigned editor are pleased to present in this volume. an overview of the many facets of materials science and technology which have been the objective of intensive and systematic research work during past decades in the laboratories of the German Aerospace Research Establishment. Its contents shows clearly the interrelations between goals defined by the user. fundamentals provided by the scientists and viable solutions developed by the practical engineer. The particular personal touch which has been given to this volume by its authors in dedicating it as a farewell present to Professor Wolfgang Bunk. inspiring sci­ entist and director of the DLR Intitute of Materials Research for more than 20 years. has obviously given an added value to this important publication. Surely. this truly cooperative endeavour will render a valuable service to a large interna­ tional community of interested readers. many of them having personal links to the Institute. its director and its staff.

This is the first book in a new series - "Materials Research and Engineering" - devoted to the science and technology of materials. "Materials Research and Engineering" evolves from a previous series on "Reine und Angewand­ te Metallkunde" ("Pure and Applied Metallurgy"), which was edited by Werner Koster until his eightieth birthday in 1976. Although the present series is an outgrowth of the earlier one, it should not and cannot be regarded as a continuation. There had to be a shift of scope - and a change in presentation as well. Metallurgy is no longer an isolated art and science. Rather, it is linked by its scientific basis and tech­ nological implications to non-metallic and composite materials, as well as to processes for production, refining, shaping, surface treatment, and appli­ cation. Thus, the new series, "Materials Research and Engineering", will present up-to-date information on scientific and technological progress, as well as on issues of general relevance within the engineering field and industrial society. Premiering the new series, the present book by Dieter Altenpohl gives the reader a very general outlook, in fact, a position analysis of materials and the materials industry within the framework of our contemporary technological environment. It ventures, moreover, to forecast the changes affecting this pattern in a dynamic, interdependent world. This may be an unusual way to start a scientific series - it is believed, nevertheless, to be an appropriate one.

This is the second book in a new series - "Materials Research and Engineering" - devoted to the science and technology of materials. "Materials Research and Engineering" evolves from a previous series on "Reine und Allgemeine Metallkunde", which was edited by Werner KBster until his eightieth birthday in 1976. Although the present series is an outgrowth of the earlier one, it should not and cannot be regarded as a continuation. There had to be a shift of scope - and a change in presenta­ tion as well. Metallurgy is no longer an isolated art and science. Rather, it is linked by its scientific basis and technological implications to non-metallic and composite materials, as well as to processes for production, refining, shaping, surface treatment, and application. Thus, the new series, "Materials Research and Engineering", will present up-to-date information on scientific and technological pro­ gress, as well as on issues of general relevance within the engineering field and industrial society. Following the general position analysis of materials in the present world as given in volume 1, now volume 2 focuses on a special topic: It provides a thorough treatment of theoretical, experimental, and applied aspects of superplasticity.

This is the third book in the new series "Material Research and Engineering", devoted to the science and technology of materials. "MRE" evolves from a previous series on "Reine und Angewandte Metallkunde", which was edited by Werner Koster until his eightieth birthday in 1976. For the new series, the presentation as well as the scope had to be modified. In particular, the scientific and technological links between volumes on metallic, non-metallic, and composite materials should reflect the successful development of materials science and engineering within the last two decades. Thus, the material provided by Dorre and Hlibner for the present volume is partic­ ularly welcome. Alumina as a ceramic material has received very large attention as an object of scientific investigation in all of its aspects. Additionally, it plays a leading role as a nonmetallic material in many fields of technical appli­ cation. This book deals with both aspects: in Chapter 2 (physical properties) and 3 (me­ chanical properties), H. Hlibner presents an outstanding documentation of what one might call the science of alumina, based on 560 literature references and 15 years of personal experience gained from experimental and theoretical work in university laboratories in Erlangen, Rio de Janeiro, and Hamburg. In Chapter 4 (fabrication) and 5 (applications), E.

It is the objective of the series IIMaterials Research and Engineeringll to publish information on technical facts and pro­ cesses together with specific scientific models and theories. Fundamental considerations assist in the recognition of the origin of properties and the roots of processes. By providing a higher level of understanding, such considerations form the basis for further improving the quality of both traditional and future engineering materials, as well as the efficiency of industrial operations. In a more general sense, theory helps to integrate facts into a framework which ties relations between physical equilibria and mechanisms on the one hand, product development and econo­ mical competition on the other. Aspects of environmental compati­ bili ty, conservation of resources and of socio-cul tural inter­ action form the final horizon - a subject treated in the first ll volume of this series, IIMaterials in World Perspective . The four authors of the present book endeavor to present a comprehensive picture of process modelling in the important field of metal forming and thermomechanical treatment. The reader will be introduced to the rapidly-growing new field of application of computer-aided numerical methods to the quanti­ tative simulation of complex technical processes. Extensive use is made of the state of scientific knowledge related to materials behavior under mechanical stress and thermal treat­ ment.

The atomic arrangements in condensed matter play an ever increasing role in many areas of science and technology - Materials Science and Engineering, Chemistry, Physics, Geology, Biology and Electrical, Civil, Mechanidtl and Chemical Engineering. Exciting discoveries in these fields in this century often stemmed from studies of these arrangements using diffraction: the structure and functions of DNA and other biological molecules, the configuration of polymer chains, the crystalline nature of metals and their imperfections, semiconductors and insulators, and -the links between their structures, their defects and material properties, and the interaction between materials and the environment. The broad, interdisciplinary character of diffraction studies makes them particularly exciting. With new tools such as the high-resolution electron microscope, new detectors, new techniques (such as EXAFS and glancing angle diffraction) and the new sources, the horizons of this field greatly expanded in the 1950's and 60's. Pulsed neutron sources and high intensity storage rings that came on the scene in the late 70's have opened up possibilities for new study to such vast horizons that it is hard to sit here writing this - there's so much to be done! Within the walls bounding each field of science or engineering, diffraction and structure is only one specialty. It is too easy for this topic to be developed in such a narrow way that sight is lost of the basic principles and broad possibilities.