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Understanding

Materials Science

Second Edition

Springer

New York Berlin Heidelberg Hong Kong London Milan Paris Tokyo

Rolf E. Hummel College of Engineering University of Florida Gainesville, FL 32601 USA

Cover illustration : Rubens N Vulcano Cat. 1676. © Museo Nacional del Prado-Madrid. Reproduced with permission.

Library of Congress Cataloging-in-Publication Data Hummel, Rolf E., 1934– Understanding materials science / Rolf E. Hummel.—2nd ed. p. cm. Includes bibliographical references and index. ISBN 0-387-20939-5 (alk. paper)

1. Materials science. I. Title. TA401.6.A1H86 2004 620.1’1—dc22 2004041693

ISBN 0-387-20939-5 Printed on acid-free paper.

© 2004, 1998 Springer-Verlag New York, LLC. All rights reserved. This work may not be translated or copied in whole or in part with- out the written permission of the publisher (Springer-Verlag, New York, LLC., 175 Fifth Avenue, New York, NY 10010, USA), except for brief excerpts in connection with re- views or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use of general descriptive names, trade names, trademarks, etc., in this publica- tion, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may ac- cordingly be used freely by anyone.

Printed in the United States of America. (MP/HAM)

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Springer-Verlag is a part of Springer Science Business Media

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Understanding the history of materials means understanding

the history of mankind and civilization.

ties and applications of metals, alloys, ceramics, plastics, and electronic materials by means of easily understandable explana- tions and entertaining historical facts. It is also intended to raise the readers’ awareness of their obligations to society as practic- ing engineers and scientists. What has been changed compared to the first edition? Natu- rally, there is always room for improvement. Accordingly, a large number of additions, corrections, and clarifications have been made on almost each page. Furthermore, the treatment of “high- tech ceramics” has been substantially expanded (mostly at the suggestions of my colleagues) by including topics such as silicon nitride ceramics, transformation-toughened zirconia, alumina, ultra-hard ceramics, and bioceramics. A separate section on com- posite materials has been added, including fiber-reinforced composites, particular composites, and laminar composites. A section on advanced fabrics seemed to be of interest to the read- ers. Most of all, however, Chapter 18 (Economic and Environ- mental Considerations) has been rewritten and expanded in many places by updating the statistical information on prices of materials, production figures, world reserves, consumption (par- ticularly oil), recycling (particularly plastics, paper, household batteries, electronic scrap, automobiles), the possible use of “bio- diesel” (rape plant oil), waste prevention, lead-free solder, energy savings through recycling, efficient design, and stability of ma- terials. The iron and steel production statistics were updated in Chapter 7, and new figures on gold production and consumption were included in Chapter 17. Finally, considerations on new trends such as “nanomaterials by severe plastic deformation,” a rendition of Moore’s law, and more philosophical remarks on the expected ethical behavior of engineers have been incorporated into Chapter 19. A few readers have suggested that I should provide the com- plete solutions for the homework problems. I am against this. The exercises should be challenges (some more, some less). Giv- ing the detailed solution of the problems (rather than just the numerical results) would tempt many students not to work the problems and in turn would deprive them of an important learn- ing experience and the satisfaction of having succeeded through perseverance. I can assure the readers, however, from my own experience that all problems are solvable. Those readers who like interactive communication and ani- mated visualizations by using the computer are directed to the post scriptum of the Preface to the First Edition that follows. My thanks go to many of my students who, through their kind words of praise and their challenging questions, helped me to

viii Preface to the Second Edition

Preface to the Second Edition ix

clarify many points. My colleagues, such as Professor Emeritus Gerold (MPI Stuttgart/Germany), Professor Emeritus Petzow (MPI Stuttgart/Germany), Professor Emeritus Hench (Imperial College London), and Professors Ebrahimi, Sigmund, and Me- cholsky (University of Florida) helped with valuable suggestions which are much appreciated.

Rolf E. Hummel Gainesville, FL June 2004

and thermal properties of all materials including textiles, fibers, paper, cement, and wood in a balanced and easily understand- able way. This book is not an encyclopedia of materials science. Indeed, it is limited in its depth so that the content can be con- veniently taught in a one-semester (15-week), three-credit-hour course. Nevertheless, the topics are considered to be essential for introducing engineers and other interested readers to the fasci- nating field of materials science. Plenty of applied problems are given at the end of the techni- cal chapters. The solutions for them are listed in the Appendix. The presentation follows an unusual sequence, starting with a description of the properties of the first materials utilized by man, such as stone, fiber, and copper. Subsequently, the differences between these materials are explained by considering their atom- istic structure, the binding forces between the atoms, and their crystallography. A description of the Bronze Age is followed by the treatment of alloys and various strengthening mechanisms which are achieved when multiple constituents are blended to compounds. The properties of iron and steel are explained only after an extensive history of iron and steel making has been pre- sented. In Part II, the electronic properties of materials are cov- ered from a historical, as well as from a scientific, point of view. Eventually, in Part III the historic development and the proper- ties of ceramics, glass, fibers and plastics as we understand them today are presented. The book concludes with a chapter on eco- nomics, world resources, recycling practices, and ecology of ma- terials utilization. Finally, an outlook speculating on what mate- rials might be utilized 50 years from now is given. Color reproductions of relevant art work and artifacts are included in an insert to show the reader how materials science is interwo- ven with the development of civilization. This book is mainly written for engineering, physics, and ma- terials science students who seek an easily understandable and enjoyable introduction to the properties of materials and the laws of physics and chemistry which govern them. These students (and their professors) will find the mixture of history, societal issues, and science quite appealing for a better understanding of the con- text in which materials were developed. I hope, however, that this book also finds its way into the hands of the general read- ership which is interested in the history of mankind and civi- lization as it relates to the use and development of materials. I trust that these readers will not stop at the end of the historical chapters, but instead will continue in their reading. They will dis- cover that the technical sections are equally fascinating since they provide an understanding of the present-day appliances and tech-

xii Preface to the First Edition

Preface to the First Edition xiii

nical devices which they use on a daily basis. In other words, I hope that a sizeable readership also comes from the humanities. Last, but not least, future archaeo-metallurgists should find the presentation quite appealing and stimulating. A book of this broad spectrum needs, understandably, the ad- vice of many specialists who are knowledgeable in their respec- tive fields. It is my sincere desire to thank all individuals who in one way or another advised me after I wrote the first draft of the manuscript. One individual above all stands out particularly: Dr. Volkmar Gerold, Professor Emeritus of the University of Stuttgart and the Max-Planck-Institut for Materials Research who read the manuscript more than once and saw to it that each definition and each fact can stand up to the most rigid scrutiny. My sin- cere thanks go to him for the countless hours he spent on this project. Other colleagues (most of them from the University of Florida) have read and advised me on specific chapters. Among them, Dr. R.T. DeHoff (diffusion and general metallurgy), Dr. A. Brennan (polymers), and Dr. E.D. Verink (corrosion) are particularly thanked. Further, Drs. C. Batich and E. Douglas (polymers), Drs. D. Clark, J. Mecholsky, and D. Whitney (ceramics), Dr. C. Beatty (recycling), Dr. J.D. Livingston (MIT; magnetism), Dr. C. Pastore (Philadelphia College of Textiles and Science; fibers), Mr. E. Co- hen (Orlando, FL) and Mr. R.G. Barlowe (U.S. Department of Agriculture, World Agricultural Outlook Board) need to be grate- fully mentioned. Ms. Tita Ramirez cheerfully typed the manu- script with great skill and diligence. Finally, Dr. M. Ludwig car- ried on my research work at those times when my mind was completely absorbed by the present writings. To all of them my heartfelt thanks.

Rolf E. Hummel Gainesville, FL April 1998

P.S. For those readers who want to deepen their understanding in selected technical topics covered in this book and who have a propensity to the modern trend of playing with the computer, I recommend considering a computer software entitled “Materials Science: A Multimedia Approach” by J.C. Russ (PWS Publishing Comp. Boston/Ma; http://www. pws.com). This CD-ROM provides animated visualizations of physical principles and interactive sample problems.

PART II: ELECTRONIC PROPERTIES OF MATERIALS

PART I

MECHANICAL

PROPERTIES

OF MATERIALS

Materials have accompanied mankind virtually from the very be- ginning of its existence. Among the first materials utilized by man were certainly stone and wood, but bone, fibers, feathers, shells, animal skin, and clay also served specific purposes. Materials were predominantly used for tools, weapons, uten- sils, shelter, and for self-expression, that is, for creating decora- tions or jewelry. The increased usage and development of ever more sophisticated materials were paralleled by a rise of the con- sciousness of mankind. In other words, it seems to be that ad- vanced civilizations generally invented and used more elaborate materials. This observation is probably still true in present days. Materials have been considered of such importance that his- torians and other scholars have named certain ancient periods after the material which was predominantly utilized at that re- spective time. Examples are the Stone Age , the Copper–Stone Age (Chalcolithic^1 Period) , the Bronze Age , and the Iron Age. The Stone Age, which is defined to have begun about 2.5 million years ago, is divided into the Paleolithic (Old Stone Age), the Mesolithic (Middle Stone Age), and the Neolithic (New Stone Age) phases. We will consider on the following pages mostly the Neolithic and Chalcolithic periods. Surprisingly, these classifications do not in- clude a Ceramics Age , even though pottery played an important role during extended time periods (see Chapter 15).

The First Materials

(Stone Age and

Copper–Stone Age)

(^1) Chalcos (Greek)
copper; lithos (Greek)
stone.

FIGURE 1.1. Copper pendant found in a cave in northeast Iraq; about 9500 B.C. The shape was obtained by hammering native copper or by carving copper ore. (Reprinted by permission from C.S. Smith, Metallurgy as a Human Experi- ence (1977), ASM International, Materials Park, OH, Figure 2.)

1 • The First Materials (Stone Age and Copper–Stone Age) 5

(^1) See the map on the rear endpaper for locations cited in the following discussion.

This transition, incidentally, did not occur at the same time in all places of the world. The introduction of metals stretched over nearly 5,000 years, if it occurred at all, and seems to have begun independently at various locations. For example, metals were used quite early in Anatolia, the bridge between Asia and Europe (part of today’s Turkey),^1 where a highly developed civilization existed which cultivated seed-bearing grasses (wheat and barley) and domesticated such animals as cattle, sheep, and goats. The transition from a nomadic to a settled society left time for ac- tivities other than concerns for everyday gathering of food. Thus, man’s interest in his environment, for example, in native copper, gold, silver, mercury, or lead, is understandable. Neolithic man must have found out that metals in their native state (that is, not combined with other elements, as in ores) can be deformed and hardened by hammering or can be softened by heat- ing. Pieces of native metals were probably quite valuable because they were rare. Still, these pure metals were generally too soft to replace, to a large extent, tools and weapons made of stone. Thus, pure metals, particularly copper, silver, and gold , were mostly used for ceremonial purposes and to create ornaments or decorations. As an example, one of the very earliest copper artifacts, a 2.3-cm long, oval-shaped pendant is shown in Figure 1.1. It was found in a cave in northeast Iraq (Shanidar). It is believed that it has been created around 9500 B.C. by hammering native copper or possibly by carving copper ore. Utensils made of metal must have lent some prestige to their owner. Copper, in particular, played an outstand- ing role because of its appearance and its relative abundance (es- pecially after man learned how to smelt it). In short, the stone and

copper ages coexisted for a long time. This led to the above-men- tioned name, Chalcolithic, or Copper–Stone Age. The exact time when Neolithic man begun to use copper will probably never be exactly known, but it is believed that this was about 8000 B.C. Copper weapons and utensils were found in Egypt- ian graves dating about 5000 B.C. The epics of Shu Ching mention the use of copper in China at 2500 B.C. Native copper for orna- ments is believed to have been used in the Lake Superior area in Michigan (USA) starting A.D. 100–200 where rich deposits of native copper are present. (Other scholars date Native American copper use as early as 4000 B.C.) Eventually, native copper and other metals must have been nearly exhausted. Thus, Neolithic man turned his attention to new sources for metals, namely, those that were locked up in minerals. A widely used copper ore is malachite (Plate 1.3). It is plentiful in certain regions of the earth such as in Anatolia, or on the Sinai peninsula. Other regions, such as Cyprus, contain chalcopyrite (a copper-iron sulfide). Now, the smelting of cop- per from copper ore, that is, the separation of copper from oxy- gen, sulphur, and carbon, was (and is), by no means, a trivial task. It requires intense heat, that is, temperatures above the melting point of pure copper (1084°C) and a “reducing atmos- phere”; in other words, an environment that is devoid of oxygen and rich in carbon monoxide. The latter is obtained by burning wood or charcoal. When all conditions are just right, the oxygen is removed from the copper ore and combines with carbon monoxide to yield gaseous carbon dioxide, which is allowed to escape. Finally, a fluxing agent , for example, iron ore, assists in

6 1 • The First Materials (Stone Age and Copper–Stone Age)

Bellows

Cu

Charcoal, Ore, Flux

Tuyere Slag

Bricks

Clay

FIGURE 1.2. Schematic representation of an ancient copper smelting furnace which was charged with a mixture of charcoal, copper ore, and flux (e.g., iron ore). The oxygen was provided by forcing air into the furnace by means of foot-operated bellows.