INTRODUCTION TO MECHANICAL METALLURGY BY GEORGE E Mechanical metallurgy is the area of metallurgy which is concerned. Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds. Office Hours. Mo and Wed pm to pm e-mail [email protected] [email protected] G.E. Dieter; Mechanical Metallurgy; Mc Graw Hill. M.A. Meyers.
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Mechanical Metallurgy. GEORGE E. DIETER, JR. Professor and Head of Department of Metallurgical. Engineering. Drexel Institute of Technologij. Philadelphia. Introduction to Physical Metallurgy by Sidney Avner · Mechanical Metallurgy by George E. Dieter · Foundry Technology by Peter Beeley. Mechanical metallurgy / George E. Dieter. Article with Cite this publication. George Ellwood. Dieter. Abstract. Incluye índice. Ad Request Full-text Paper PDF.
Would you like to tell us about a lower price? If you are a seller for this product, would you like to suggest updates through seller support? Examines the behaviour of materials under stress and their reaction to a variety of hostile environments. This book covers mechanical metallurgy, from an understanding of the continuum description of stress and strain, through crystalline and defect mechanisms of flow and fracture, and on to a consideration of major mechanical property tests. Read more Read less. Frequently bought together. Total price:
A continuous body is one which does not contain voids or empty spaces of any kind. A body is homogeneous if it has identical properties at all points. A body is considered to be isotropic with respect to some property when that property does not vary with direction or orientation. A property which varies with orientation with respect to some system of axes is said to be anisotropic.
While engineering materials such as steel, cast iron, and aluminum may appear to meet these conditions when viewed on a gross scale, it is readily apparent when they are viewed through a microscope that they are anything but homogeneous and isotropic.
Most engineering metals are made up of more than one phase, with different mechanical properties, such that on a micro scale they are heterogeneous.
Further, even a single-phase metal will usually exhibit chemical segregation, and therefore the properties will not be identical from point to point.
Metals are made up of an aggregate of crystal grains having different properties in different crystallographic directions.
The reason why the equations of strength of materials describe the behavior of real metals is that, in gneral, the crystal grains are so small that, for a specimen of any macroscopic volume, the materials are statistically homogeneous and isotropic. However, when metals are severely deformed in a particular direction, as in rolling or forging, the mechanical properties may be anisotropic on a macro scale. Other examples of anisotropic properties are fiber-reinforced composite materials and single crystals.
Lack of continuity may be present in porous castings or powder metallurgy parts and, on an atomic level, at defects such as vacancies and dislocations. It is further found that up to certain limiting loads a solid will recover its original dimensions when the load is removed. The recovery of the original dimensions of a deformed body when the load is removed is known as elastic behavior.
The limiting load beyond which the material no longer behaves elastically is the elastic limit. If the elastic limit is exceeded, the body will experience a permanent set or deformation when the load is removed. A body which is permanently deformed is said to have undergone plastic deformation. For most materials, as long as the load does not exceed the elastic limit, the deformation is proportional to the load. This relationship is known as Hooke's law; it is more frequently stated as stress is proportional to strain.
Hooke's law requires that the load-deformation relationship should be linear. However, it does not necessarily follow that all materials which behave elastically will have a linear stress-strain relationship. Rubber is an example of a material with a nonlinear stress-strain relationship that still satisfies the definition of an elastic material.
This is, however, primarily of academic importance.
While part of the material covered in this chapter is a review of information generally covered in strength of materials, the subject is extended beyond this point to a consideration of stress and strain in three dimensions. The material included in this chapter is important for an understanding of most of the phenomenological aspects of mechanical metallurgy, and for this reason it should be given careful attention by those readers to whom it is unfamiliar.
In the space available for this subject it has not been possible to carry it to the point where extensive problem solving is possible. The material covered here should, however, provide a background for intelligent reading of the more mathematical literature in mechanical metallurgy. It should be recognized that the equations describing the state of stress or strain in a body are applicable to any solid continuum, whether it be an elastic or plastic solid or a viscous fluid.
Indeed, this body of knowledge is often called continuum mechanics. The equations relating stress and strain are called constitutive equations because they depend on the material behavior.
In this chapter we shall only consider the constitutive equations for an elastic solid.
It is the oldest of the metalworking arts, having its origin with the primitive blacksmith of Biblical times. The development of machinery to replace the arm of the smith occurred early during the Industrial Revolution. Today there is a wide variety of forging machinery which is capable of making parts ranging in size from a bolt to a turbine rotor or an entire airplane wing.
Most forging operations are carried out hot, although certain metals may be cold-forged. Two major classes of equipment are used for forging operations. The forging hammer, or drop hammer, delivers rapid impact blows to the surface of the metal, while the forging press subjects the metal to a slow-speed compressive force. The two broad categories of forging processes are open-die forging and closed-die forging. Open-die forging is carried out between fiat dies or dies of very simple shape.
The process is used mostly for large objects or when the number of parts produced is small. Often open-die forging is used to preform the workpiece for closed-die forging.
In some sections advanced material intended primarily for graduate students has been set in smaller type. The problems have been extensively revised and expanded, and a solutions manual has been prepared. In total, more than one-half of the book has been rewritten completely.
Since it is not a precisely defined area, it will mean different things to different persons. To some it will mean mechanical properties of metals or mechanical testing, others may consider the field restricted to the plastic working and shaping of metals, while still others confine their interests to the more theoretical aspects of the field, which merge with metal physics and physical metallurgy.
Still another group may consider that mechanical metallurgy is closely allied with applied mathematics and applied mechanics. In writing this book an attempt has been made to cover, in some measure, this great diversity of interests. The objective has been to include the entire scope of mechanical metallurgy in one fairly comprehensive volume. The book has been divided into four parts. Patt One, Mechanical Fundamentals, presents the mathematical framework for many of the chapters which follow.
The concepts of combined stress and strain are reviewed and extended into three dimensions.
Detailed consideration of the theories of yielding and an introduction to the concepts of plasticity are given. No attempt is made to carry the topics in Part One to the degree of completion required for original problem solving. Instead, the purpose is to acquaint metallurgically trained persons with the mathematical language encountered in some areas of mechanical metallurgy.
Part Two, Metallurgical Fundamentals, deals with the structural aspects of plastic deformation and fracture. Emphasis is on the atornistics of flow and fracture and the way in which metallurgical structure affects these processes. The concept of the dislocation is introduced early in Part Two and is used throughout to provide qualitative explanations for such phenomena as strain hardening, the yield point, dispersed phase hardening, and fracture. A more mathematical treatment of the properties of dislocations is given in a separate chapter.
The topics covered in Part Two stem from physical metallurgy. Certain topics that are more physical metallurgy than mechanical metallurgy are included to provide continuity and the necessary background for readers who have not studied modern physical metallurgy. Part Three, Applications to Materials Testing, deals with the engineering aspects of the common testing techniques of mechanical failure of metals.
Chapters are devoted to the tension, torsion, hardness, fatigue, creep, and impact tests. Others take up the important subjects of residual stresses and the statistical analysis of mechanical-property data.
In Part Three emphasis is placed on the interpretation of the tests and on the effect of metallurgical variables on mechanical behavior rather than on the procedures for conducting the tests.
It is assumed that the actual performance of these tests will be covered in a concurrent laboratory course or in a separate course. Part Four, Plastic Forming of Metals, deals with the common mechanical processes for producing useful metal shapes. Little emphasis is given to the descriptive aspects of this subject, since this can best be covered by plant trips and illustrated lectures.
Instead, the main attention is given to the mechanical and metallurgical factors which control each process such as forging, rolling, extrusion, drawing, and sheet-metal forming. This book is written for the senior or first-year graduate student in metallurgical or mechanical engineering, as well as for practicing engineers in industry. While most universities have instituted courses in mechanical metallurgy or mechanical properties, there is a great diversity in the material covered and in the background of the students taking these courses.
Thus, for the present there can be nothing like a standardized textbook on mechanical metallurgy. It is hoped that the breadth and scope of this book will provide material for these somewhat diverse requirements.
It is further hoped that the existence of a comprehensive treatment of the field of mechanical metallurgy will stimulate the development of courses which cover the total subject.
Since this book is intended for college seniors, graduate students, and practicing engineers, it is expected to become a part of their professional library. Although there has been no attempt to make this book a handbook, some thought has been given to providing abundant references to the literature on mechanical metallurgy. Therefore, more references are included than is usual in the ordinary textbook.
References have been given to point out derivations or analyses beyond the scope of the book, to provide the key to further information on controversial or detailed points, and to emphasize important papers which are worthy of further study. In addition, a bibliography of general references will be found at the end of each chapter.
A collection of problems is included at the end of the volume. This is primarily for the use of the reader who is engaged in industry and who desires some check on his comprehension of the material.