Structure Of Metals Through Optical Microscopy

Methods of scientific investigation can be divided into two categories: they are either macroscopic or microscopic in nature. The former are generally older, classical methods where the sample as a whole is studied and various local prop erties are deduced by differentiation. The microscopic methods, on the other hand, have been discovered and developed more recently, and they operate for the most part on an atomistic scale. Glancing through the shelves of books on the various scientific fields, and, in particular, on the field of physical metallurgy, we are surprised at how lit tle consideration has been given to the microscopic methods. How these tools provide new insight and information is a question which so far has not at tracted much attention. Similar observations can be made at scientific confer ences, where the presentation of papers involving microscopic methods is often pushed into a far corner. This has led users of such methods to organize their own special conferences. The aim of this book is to bridge the present gap and encourage more interaction between the various fields of study and selected microscopic meth ods, with special emphasis on their suitability for investigating metals. In each case the principles of the method are reviewed, the advantages and successes pointed out, but also the shortcomings and limitations indicated.

Metallurgical Microscopy provides the general principles, methods, and techniques in metallurgical microscopy. The book initially provides the techniques for specimen preparation for macroscopic and microscopic examination. Subsequent chapters are devoted to the discussion of light-optical microscopy and photography, interferometry and contrast-raising methods, and microhardness measurement. Topics on high-temperature microscopy, a brief review of the electron microprobe and its applications, and the construction, properties and applications of the electron microscope are presented as well. Metallurgists and materials scientists will find the book very informative and useful.

During recent years, people involved in developing new metals and materials for use in some of the rather extreme conditions of stress, temperature, and environment have relied heavily on the microstructural condition of their materials. In fact, many of the newer materials, such as dispersion-strengthened alloys, have been designed almost entirely by first determining the microstruc ture desired and then finding the right combination of composition, heat treatment, and mechanical working that will result in the de sired microstructure. Furthermore, the extremely high reliability required of materials used today, for example, in aerospace and nuclear energy systems, requires close control on the microstruc tural conditions of materials. This is clearly evident from even a cursory examination of recently written specifications for mate rials where rather precise microstructural parameters are stipu lated. Whereas specifications written several years ago may have included microstructural requirements for details such as ASTM grain size or graphite type, today's specifications are beginning to include such things as volume fraction of phases, mean free path of particles, and grain intercept distances. Rather arbitrary terms such as "medium pearlite" have been replaced by requirements such as "interlamella spacing not to exceed 0. 1 micron. " Finally, materials users have become increasingly aware that when a material does fail, the reason for its failure may be found by examining and "reading" its microstructure. The responsibility for a particular microstructure and a resulting failure is a matter of growing importance in current product liability consider ations.

/.letallography is much more than taking striking pictures at high magnifications or polishing and etching specimens in such a way that no scratches can be seen. Basically, metallography is the physical metallurgist's most useful and most used tool for studying metals. Although it is perhaps his oldest tool, it certainly is not likely to become obsolete. Rather, the continued demands that have been placed upon materials have required more detailed charac terizations of their microstructures and this, in turn, has re quired the metallographer to develop new techniques to make these characterizations. Not too many years ago, the metallographer had only optical microscopes with which to examine his specimens. Now he has elec tron microscopes, scanning electron microscopes, and a whole host of instruments which were unknown to him only a relatively few years ago. This has forced him to learn not only how to use these new instruments and how to interpret the information that they provide but it also has made him develop new techniques for preparing the samples for examination.

This early work on the structure of metals is both expensive and hard to find in its first edition. Its 579 pages contain a wealth of information on the physical properties and chemistry of various metals. This is a fascinating work and is thoroughly recommended for students of metallurgy. Many of the earliest books, particularly those dating back to the 1900s and before, are now extremely scarce. We are republishing these classic works in affordable, high quality, modern editions, using the original text and artwork.

Electron Microscopy of Interfaces in Metals and Alloys examines the structure of interfaces in metals and alloys using transmission electron microscopy. The book presents quantitative methods of analysis and reviews the most significant work on interface structure over the last 20 years. It provides the first book description of the methods used for quantitative identification of Burgers vectors of interfacial dislocations, including the geometric analysis of periodicities in interface structure and the comparison of experimental and theoretical electron micrographs. The book explores low- and high-angle grain boundaries and interphase interfaces between neighboring grains, emphasizing interfacial dislocations and rigid-body displacements to the structure and properties of interfaces. It also analyzes the use of two-beam images and diffraction patterns for analysis and studies n-beam lattice imaging. The book includes numerous worked examples of the analysis of the structure of grain boundaries and interphase interfaces, which are particularly useful to those who need to consider the nature of intercrystalline interfaces.