Characteristics of Selected Elements
Atomic Density of Crystal Atomic Ionic Most Melting Atomic Weight Solid, 20⬚C Structure, Radius Radius Common Point Element Symbol Number (amu) (g/cm3) 20⬚C (nm) (nm) Valence (⬚C)
Aluminum Al 13 26.98 2.71 FCC 0.143 0.053 3⫹ 660.4
Argon Ar 18 39.95 — — — — Inert ⫺189.2
Barium Ba 56 137.33 3.5 BCC 0.217 0.136 2⫹ 725
Beryllium Be 4 9.012 1.85 HCP 0.114 0.035 2⫹ 1278
Boron B 5 10.81 2.34 Rhomb. — 0.023 3⫹ 2300
Bromine Br 35 79.90 — — — 0.196 1⫺ ⫺7.2
Cadmium Cd 48 112.41 8.65 HCP 0.149 0.095 2⫹ 321
Calcium Ca 20 40.08 1.55 FCC 0.197 0.100 2⫹ 839
Carbon C 6 12.011 2.25 Hex. 0.071 ⬃0.016 4⫹ (sublimes at 3367)
Cesium Cs 55 132.91 1.87 BCC 0.265 0.170 1⫹ 28.4
Chlorine Cl 17 35.45 — — — 0.181 1⫺ ⫺101
Chromium Cr 24 52.00 7.19 BCC 0.125 0.063 3⫹ 1875
Cobalt Co 27 58.93 8.9 HCP 0.125 0.072 2⫹ 1495
Copper Cu 29 63.55 8.94 FCC 0.128 0.096 1⫹ 1085
Fluorine F 9 19.00 — — — 0.133 1⫺ ⫺220
Gallium Ga 31 69.72 5.90 Ortho. 0.122 0.062 3⫹ 29.8
Germanium Ge 32 72.64 5.32 Dia. cubic 0.122 0.053 4⫹ 937
Gold Au 79 196.97 19.32 FCC 0.144 0.137 1⫹ 1064
Helium He 2 4.003 — — — — Inert ⫺272 (at 26 atm)
Hydrogen H 1 1.008 — — — 0.154 1⫹ ⫺259
Iodine I 53 126.91 4.93 Ortho. 0.136 0.220 1⫺ 114
Iron Fe 26 55.85 7.87 BCC 0.124 0.077 2⫹ 1538
Lead Pb 82 207.2 11.35 FCC 0.175 0.120 2⫹ 327
Lithium Li 3 6.94 0.534 BCC 0.152 0.068 1⫹ 181
Magnesium Mg 12 24.31 1.74 HCP 0.160 0.072 2⫹ 649
Manganese Mn 25 54.94 7.44 Cubic 0.112 0.067 2⫹ 1244
Mercury Hg 80 200.59 — — — 0.110 2⫹ ⫺38.8
Molybdenum Mo 42 95.94 10.22 BCC 0.136 0.070 4⫹ 2617
Neon Ne 10 20.18 — — — — Inert ⫺248.7
Nickel Ni 28 58.69 8.90 FCC 0.125 0.069 2⫹ 1455
Niobium Nb 41 92.91 8.57 BCC 0.143 0.069 5⫹ 2468
Nitrogen N 7 14.007 — — — 0.01–0.02 5⫹ ⫺209.9
Oxygen O 8 16.00 — — — 0.140 2⫺ ⫺218.4
Phosphorus P 15 30.97 1.82 Ortho. 0.109 0.035 5⫹ 44.1
Platinum Pt 78 195.08 21.45 FCC 0.139 0.080 2⫹ 1772
Potassium K 19 39.10 0.862 BCC 0.231 0.138 1⫹ 63
Silicon Si 14 28.09 2.33 Dia. cubic 0.118 0.040 4⫹ 1410
Silver Ag 47 107.87 10.49 FCC 0.144 0.126 1⫹ 962
Sodium Na 11 22.99 0.971 BCC 0.186 0.102 1⫹ 98
Sulfur S 16 32.06 2.07 Ortho. 0.106 0.184 2⫺ 113
Tin Sn 50 118.71 7.27 Tetra. 0.151 0.071 4⫹ 232
Titanium Ti 22 47.87 4.51 HCP 0.145 0.068 4⫹ 1668
Tungsten W 74 183.84 19.3 BCC 0.137 0.070 4⫹ 3410
Vanadium V 23 50.94 6.1 BCC 0.132 0.059 5⫹ 1890
Zinc Zn 30 65.41 7.13 HCP 0.133 0.074 2⫹ 420
Zirconium Zr 40 91.22 6.51 HCP 0.159 0.079 4⫹ 1852
Values of Selected Physical Constants
Quantity Symbol SI Units cgs Units
Avogadro’s number NA 6.022 ⫻1023 6.022 ⫻1023 molecules/mol molecules/mol Boltzmann’s constant k 1.38 ⫻10⫺23J/atom K 1.38 ⫻10⫺16erg/atom K
8.62 ⫻10⫺5eV/atom K Bohr magneton B 9.27 ⫻10⫺24A m2 9.27 ⫻10⫺21erg/gaussa Electron charge e 1.602 ⫻10⫺19C 4.8 ⫻10⫺10statcoulb Electron mass — 9.11 ⫻10⫺31kg 9.11 ⫻10⫺28g
Gas constant R 8.31 J/mol K 1.987 cal/mol K
Permeability of a vacuum 0 1.257 ⫻10⫺6henry/m unitya Permittivity of a vacuum ⑀0 8.85 ⫻10⫺12farad/m unityb
Planck’s constant h 6.63 ⫻10⫺34J s 6.63 ⫻10⫺27erg s 4.13 ⫻10⫺15eV s Velocity of light in a vacuum c 3 ⫻108m/s 3 ⫻1010cm/s aIn cgs-emu units.
bIn cgs-esu units.
#
#
#
#
#
#
#
#
#
Unit Abbreviations
A ⫽ampere in.⫽inch N ⫽newton
⫽angstrom J ⫽joule nm ⫽nanometer
Btu ⫽British thermal unit K ⫽degrees Kelvin P ⫽poise
C ⫽Coulomb kg ⫽kilogram Pa ⫽Pascal
⫽degrees Celsius lbf⫽pound force s ⫽second cal ⫽calorie (gram) lbm⫽pound mass T⫽temperature cm ⫽centimeter m ⫽meter m ⫽micrometer eV ⫽electron volt Mg ⫽megagram (micron)
⫽degrees Fahrenheit mm ⫽millimeter W ⫽watt
ft ⫽foot mol ⫽mole psi ⫽pounds per square
g ⫽gram MPa ⫽megapascal inch
°F °C Å
SI Multiple and Submultiple Prefixes Factor by Which
Multiplied Prefix Symbol
109 giga G
106 mega M
103 kilo k
10⫺2 centia c
10⫺3 milli m
10⫺6 micro
10⫺9 nano n
10⫺12 pico p
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E
I G H T HE
D I T I O NMaterials Science
and Engineering
An Introduction
William D. Callister, Jr.
Department of Metallurgical Engineering The University of Utah
David G. Rethwisch
Department of Chemical and Biochemical Engineering The University of Iowa
John Wiley & Sons, Inc.
Front Cover: Depiction of a unit cell for the inverse spinel crystal structure. Red spheres represent
O2⫺oxygen ions; dark blue and light blue spheres denote Fe2⫹and Fe3⫹iron ions, respectively. (As
dis-cussed in Chapter 20, some of the magnetic ceramic materials have this inverse spinel crystal structure.)
Back Cover: The image on the right shows the ionic packing of a close-packed plane for the inverse spinel
crystal structure. The relationship between this close-packed plane and the unit cell is represented by the image on the left; a section has been taken through the unit cell, which exposes this close-packed plane.
VICE PRESIDENT AND EXECUTIVE PUBLISHER Donald Fowley
ACQUISITIONS EDITOR Jennifer Welter
EDITORIAL PROGRAM ASSISTANT Alexandra Spicehandler
PRODUCTION SERVICES MANAGER Dorothy Sinclair
PRODUCTION EDITOR Janet Foxman
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PHOTO EDITOR Hilary Newman
PHOTO RESEARCHER Teri Stratford
ILLUSTRATION EDITOR Anna Melhorn
MEDIA EDITOR Lauren Sapira
PRODUCTION SERVICES Elm Street Publishing Services
COVER ART Roy Wiemann and Bill Callister
This book was set in Times Ten Roman 10/12 by Aptara, Inc., and printed and bound by World Color USA/Versailles. The cover was printed by World Color USA/Versailles.
This book is printed on acid-free paper.
Copyright © 2010, 2007, 2003, 2000 John Wiley & Sons, Inc. All rights reserved. No part of this publi-cation may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, website www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030-5774, (201) 748-6011, fax (201) 748-6008, website www.wiley.com/go/permissions.
Evaluation copies are provided to qualified academics and professionals for review purposes only, for use in their courses during the next academic year. These copies are licensed and may not be sold or transferred to a third party. Upon completion of the review period, please return the evaluation copy to Wiley. Return instructions and a free of charge return shipping label are available at
www.wiley.com/go/returnlabel. Outside of the United States, please contact your local representative.
Library of Congress Cataloging-in-Publication Data
Callister, William D.,
1940-Materials science and engineering: an introduction / William D. Callister, Jr., David G. Rethwisch.–8th ed. p. cm.
Includes index.
ISBN 978-0-470-41997-7 (cloth)
1. Materials. I. Rethwisch, David G. II. Title.
TA403.C23 2009 620.1’1—dc22
2009023130
L.C. Call no. Dewey Classification No. L.C. Card No.
ISBN 978-0-470-41997-7 (Main Book)
ISBN 978-0-470-55673-3 (Binder-Ready Version)
Printed in the United States of America 10 9 8 7 6 5 4 3 2 1
q
Dedicated to
our wives, Nancy and Ellen, whose love, patience, and understanding
have helped make this volume possible
I
n this Eighth Edition we have retained the objectives and approaches for teach-ing materials science and engineerteach-ing that were presented in previous editions. The first, and primary, objective is to present the basic fundamentals on a level appro-priate for university/college students who have completed their freshmen calculus, chemistry, and physics courses. In order to achieve this goal, we have endeavored to use terminology that is familiar to the student who is encountering the discipline of materials science and engineering for the first time, and also to define and ex-plain all unfamiliar terms.The second objective is to present the subject matter in a logical order, from the simple to the more complex. Each chapter builds on the content of previous ones.
The third objective, or philosophy, that we strive to maintain throughout the text is that if a topic or concept is worth treating, then it is worth treating in suffi-cient detail and to the extent that students have the opportunity to fully understand it without having to consult other sources; also, in most cases, some practical rele-vance is provided. Discussions are intended to be clear and concise and to begin at appropriate levels of understanding.
The fourth objective is to include features in the book that will expedite the learning process. These learning aids include:
• Numerous illustrations, now presented in full color, and photographs to help visualize what is being presented;
• Learning objectives, to focus student attention on what they should be getting from each chapter;
• “Why Study . . .” and “Materials of Importance” items that provide relevance to topic discussions;
• “Concept Check” questions that test whether or not a student understands the subject matter on a conceptual level;
• Key terms and descriptions of key equations highlighted in the margins for quick reference;
• End-of-chapter questions and problems designed to progressively develop students’ understanding of concepts and facility with skills;
• Answers to selected problems, so that students can check their work; • A glossary, list of symbols, and references to facilitate understanding the
subject matter.
The fifth objective is to enhance the teaching and learning process by using the newer technologies that are available to most instructors and students of engi-neering today.
• vii
F
EATUREST
HATA
REN
EW TOT
HISE
DITION New/Revised ContentSeveral important changes have been made with this Eighth Edition. One of the most significant is the incorporation of a number of new sections, as well as revisions/ amplifications of other sections. New sections/discussions are as follows:
• Diffusion in semiconductors (Section 5.6). • Flash memory (in Section 18.15).
• “Biodegradable and Biorenewable Polymers/Plastics” Materials of Importance piece in Chapter 22.
Other revisions and additions include the following: • Expanded discussion on nanomaterials (Section 1.5).
• A more comprehensive discussion on the construction of crystallographic directions in hexagonal unit cells—also of conversion from the three-index scheme to four-index (Section 3.9).
• Expanded discussion on titanium alloys (Section 11.3).
• Revised and enlarged treatment of hardness and hardness testing of ceram-ics (Section 12.11).
• Updated discussion on the process for making sheet glass (in Section 13.9). • Updates on magnetic storage (hard disk drives and magnetic tapes—Section
20.11).
• Minor updates and revisions in Chapter 22 (“Economic, Environmental, and Societal Issues in Materials Science and Engineering”), especially on recycling.
• Appendix C (“Costs and Relative Costs for Selected Engineering Materials”) has been updated.
• End-of chapter summaries have been revised to reflect answers/responses to the extended lists of learning objectives, to better serve students as a study guide.
• Summary table of important equations at the end of each chapter. • Summary list of symbols at the end of each chapter.
• New chapter-opener photos and layouts, focusing on applications of materials science to help engage students and motivate a desire to learn more about materials science.
• Virtually all Homework problems requiring computations have been refreshed.
Processing/Structure/Properties/Performance Correlations
One new feature that has been incorporated throughout this new edition is a track-ing of relationships among the processtrack-ing, structure, properties, and performance components for four different materials: steel alloys, glass-ceramics, polymer fibers, and silicon semiconductors.This concept is outlined in Chapter 1 (Section 1.7), which includes the presentation of a “topic timeline.” This timeline notes those locations (by section) where discussions involving the processing, structure, properties, and performance of each of these four material types are found.
These discussions are introduced in the “Why Study?” sections of appropriate chapters, and, in addition, end-of-chapter summaries with relational diagrams are also included. Finally, for each of the four materials a processing/structure/properties/
viii • Preface
performance summary appears at the end of that chapter in which the last item on the topic timeline appears.
Discipline-Specific Modules
A set of discipline-specific modules appear on the book’s web site (Student Com-panion Site). These modules treat materials science/engineering topics not covered in the print text that are relevant to specific engineering disciplines—mechanical and biomaterials.
All Chapters Now In Print
Five chapters of the previous edition were in electronic format only (i.e., not in print). In this edition, all chapters are in print.
Case Studies
In prior editions, “Materials Selection and Design Considerations” consisted of a series of case studies that were included as Chapter 22. These case studies will now appear as a library of case studies on the book’s web site (Student Compan-ion Site) at www.wiley.com/college/callister. This library includes the following:
• Materials Selection for a Torsionally Stressed Cylindrical Shaft • Automobile Valve Spring
• Failure of an Automobile Rear Axle • Artificial Total Hip Replacement • Chemical Protective Clothing
• Materials for Integrated Circuit Packages
S
TUDENTL
EARNINGR
ESOURCES(
WWW.
WILEY.
COM/
COLLEGE/
CALLISTER)
Also found on the book’s web site (Student Companion Site) are several impor-tant instructional elements for the student that complement the text; these include the following:
1. VMSE: Virtual Materials Science and Engineering. This is an expanded ver-sion of the software program that accompanied the previous edition. It consists of interactive simulations and animations that enhance the learning of key concepts in materials science and engineering, and, in addition, a materials properties/cost data-base. Students can access VMSE via the registration code included on the inside front cover of the textbook.
Throughout the book, whenever there is some text or a problem that is supple-mented by VMSE, a small “icon” that denotes the associated module is included in one of the margins. These modules and their corresponding icons are as follows:
Metallic Crystal Structures
Phase Diagrams and Crystallography
Ceramic Crystal Structures Diffusion
Repeat Unit and Polymer
Tensile Tests Structures
Dislocations Solid-Solution Strengthening
Preface • ix
2. Answers to Concept Check questions. Students can visit the web site to find the correct answers to the Concept Check questions.
3. Extended Learning Objectives—a more extensive list of learning objectives than is provided at the beginning of each chapter. These direct the student to study the subject material to a greater degree of depth.
4. Direct access to online self-assessment exercises. This is a Web-based assess-ment program that contains questions and problems similar to those found in the text; these problems/questions are organized and labeled according to textbook sec-tions. An answer/solution that is entered by the user in response to a question/problem is graded immediately, and comments are offered for incorrect responses. The student may use this electronic resource to review course material, and to assess his/her mastery and understanding of topics covered in the text.
5. Index of Learning Styles. Upon answering a 44-item questionnaire, a user’s learning style preference (i.e., the manner in which information is assimilated and processed) is assessed.
I
NSTRUCTORS’ R
ESOURCESThe Instructor Companion Site (www.wiley.com/college/callister) is available for in-structors who have adopted this text. Please visit the web site to register for access. Resources that are available include the following:
1. Instructor Solutions Manual. Detailed solutions of all end-of-chapter ques-tions and problems (in both Word® and Adobe Acrobat® PDF formats).
2. Photographs, illustrations, and tables that appear in the book. These are in both PDF and JPEG formats so that an instructor can print them for handouts or prepare transparencies in his/her desired format.
3. A set of PowerPoint® lecture slides. These slides, developed by Peter M. Anderson (The Ohio State University), and adapted by the text authors, fol-low the ffol-low of topics in the text, and include materials from the text and from other sources. Instructors may use the slides as is or edit them to fit their teach-ing needs.
4. A list of classroom demonstrations and laboratory experiments. These portray phenomena and/or illustrate principles that are discussed in the book; references are also provided that give more detailed accounts of these demon-strations.
5. Conversion guide. This guide notes, for each homework problem/question (by number), whether or not it appeared in the seventh edition of Introduction, and, if so, its number in this previous edition. Most problems have been refreshed (i.e., new numbers were assigned to values of parameters given the problem statement); refreshed problems are also indicated in this conversion guide.
6. Suggested course syllabi for the various engineering disciplines. Instructors may consult these syllabi for guidance in course/lecture organization and planning. 7. In addition, all of the student learning resources described above are avail-able on the Instructor Companion Site.
W
ILEYPLUS
This online teaching and learning environment integrates the entire digital textbook with the most effective instructor and student resources to fit every learning style.
x • Preface
With WileyPLUS:
• Students achieve concept mastery in a rich, structured environment that’s available 24/7.
• Instructors personalize and manage their course more effectively with assessment, assignments, grade tracking, and more.
WileyPLUS can complement your current textbook or replace the printed text altogether.
For Students
Personalize the learning experience
Different learning styles, different levels of proficiency, different levels of preparation— each of your students is unique. WileyPLUS empowers them to take advantage of their individual strengths:
• Students receive timely access to resources that address their demonstrated needs, and get immediate feedback and remediation when needed.
• Integrated, multi-media resources—including visual exhibits, demonstration problems, and much more—provide multiple study-paths to fit each student’s learning preferences and encourage more active learning. • WileyPLUS includes many opportunities for self-assessment linked to the
relevant portions of the text. Students can take control of their own learn-ing and practice until they master the material.
For Instructors
Personalize the teaching experience
WileyPLUS empowers you, the instructor, with the tools and resources you need to make your teaching even more effective:
• You can customize your classroom presentation with a wealth of resources and functionality from PowerPoint slides to a database of rich visuals. You can even add your own materials to your WileyPLUS course.
• With WileyPLUS you can identify those students who are falling behind and intervene accordingly, without having to wait for them to come to your office. • WileyPLUS simplifies and automates such tasks as student performance
assessment, making assignments, scoring student work, recording grades, and more.
F
EEDBACKWe have a sincere interest in meeting the needs of educators and students in the materials science and engineering community, and, therefore, would like to solicit feedback on this eighth edition. Comments, suggestions, and criticisms may be sub-mitted to the authors via e-mail at the following address: billcallister@comcast.net.
A
CKNOWLEDGMENTSSince undertaking the task of writing this and previous editions, instructors and stu-dents, too numerous to mention, have shared their input and contributions on how to make this work more effective as a teaching and learning tool. To all those who have helped, we express our sincere thanks!
Preface • xi
Appreciation is expressed to those who have made contributions to this edi-tion. We are especially indebted to Michael Salkind of Kent State University, who provided assistance in updating and upgrading important material in several chap-ters. In addition, we sincerely appreciate Grant E. Head’s expert programming skills, which he used in developing the Virtual Materials Science and Engineering software. In addition, we would like to thank instructors who helped in reviewing the manu-script, who reviewed and have written content for WileyPLUS, and, in addition, oth-ers who have made valuable contributions:
Arvind Agarwal Florida International University
Sayavur I. Bakhtiyarov New Mexico Institute of Mining and Technology Prabhakar Bandaru University of California-San Diego
Valery Bliznyuk Western Michigan University Suzette R. Burckhard South Dakota State University Stephen J. Burns University of Rochester Audrey Butler University of Iowa
Matthew Cavalli University of North Dakota Alexis G. Clare Alfred University
Stacy Gleixner San José State University Ginette Guinois Dubois Agrinovation Richard A. Jensen Hofstra University
Bob Jones University of Texas, Pan American Molly Kennedy Clemson University
Kathleen Kitto Western Washington University Chuck Kozlowski University of Iowa
Masoud Naghedolfeizi Fort Valley State University Todd Palmer Penn State University
Oscar J. Parales-Perez University of Puerto Rico at Mayaguez Bob Philipps Fujifilm USA
Don Rasmussen Clarkson University Sandie Rawnsley Murdoch University Wynn A. Ray San José State University Hans J. Richter Seagate Recording Media Joe Smith Black Diamond Equipment Jeffrey J. Swab U.S. Military Academy
Cindy Waters North Carolina Agricultural and Technical State University
Yaroslava G. Yingling North Carolina State University
We are also indebted to Jennifer Welter, Sponsoring Editor, for her assistance and guidance on this revision
Last, but certainly not least, the continual encouragement and support of our families and friends is deeply and sincerely appreciated.
WILLIAMD. CALLISTER, JR.
LIST OFSYMBOLS xxi
1. Introduction
Learning Objectives 2 1.1 Historical Perspective 2
1.2 Materials Science and Engineering 3
1.3 Why Study Materials Science and Engineering? 5 1.4 Classification of Materials 5
Materials of Importance—Carbonated Beverage Containers 10
1.5 Advanced Materials 11 1.6 Modern Materials’ Needs 13
1.7 Processing/Structure/Properties/Performance Correlations 14
Summary 16 References 17 Question 17
2. Atomic Structure and Interatomic Bonding 18
Learning Objectives 19 2.1 Introduction 19
ATOMICSTRUCTURE 19
2.2 Fundamental Concepts 19 2.3 Electrons in Atoms 20 2.4 The Periodic Table 26
ATOMICBONDING INSOLIDS 28
2.5 Bonding Forces and Energies 28 2.6 Primary Interatomic Bonds 30
2.7 Secondary Bonding or van der Waals Bonding 34
Materials of Importance—Water (Its Volume Expansion Upon Freezing) 37
2.8 Molecules 38 Summary 38
Equation Summary 39
Processing/Structure/Properties/Performance Summary 40 Important Terms and Concepts 40
References 40
Questions and Problems 41
Contents
• xiii
3. The Structure of Crystalline Solids 44
Learning Objectives 45 3.1 Introduction 45
CRYSTALSTRUCTURES 46
3.2 Fundamental Concepts 46 3.3 Unit Cells 47
3.4 Metallic Crystal Structures 47 3.5 Density Computations 51 3.6 Polymorphism and Allotropy 52 3.7 Crystal Systems 52
Materials of Importance—Tin (Its Allotropic Transformation) 53
CRYSTALLOGRAPHICPOINTS, DIRECTIONS,
ANDPLANES 55
3.8 Point Coordinates 55
3.9 Crystallographic Directions 57 3.10 Crystallographic Planes 64 3.11 Linear and Planar Densities 68 3.12 Close-Packed Crystal
Structures 70
CRYSTALLINE ANDNONCRYSTALLINE
MATERIALS 72
3.13 Single Crystals 72
3.14 Polycrystalline Materials 72 3.15 Anisotropy 73
3.16 X-Ray Diffraction: Determination of Crystal Structures 74
3.17 Noncrystalline Solids 79 Summary 80
Equation Summary 82
Processing/Structure/Properties/Performance Summary 83
Important Terms and Concepts 83 References 83
Questions and Problems 84
4. Imperfections in Solids 90
Learning Objectives 91 4.1 Introduction 91
POINTDEFECTS 92
4.2 Vacancies and Self-Interstitials 92 4.3 Impurities in Solids 93
4.4 Specification of Composition 95
MISCELLANEOUSIMPERFECTIONS 99
4.5 Dislocations–Linear Defects 99 4.6 Interfacial Defects 102
Materials of Importance—Catalysts (and Surface Defects) 105
xiv • Contents
4.7 Bulk or Volume Defects 106 4.8 Atomic Vibrations 106
MICROSCOPICEXAMINATION 107
4.9 Basic Concepts of Microscopy 107 4.10 Microscopic Techniques 108 4.11 Grain Size Determination 113
Summary 114
Equation Summary 116
Processing/Structure/Properties/Performance Summary 117
Important Terms and Concepts 118 References 118
Questions and Problems 118 Design Problems 121
5. Diffusion 122
Learning Objectives 123 5.1 Introduction 123
5.2 Diffusion Mechanisms 125 5.3 Steady-State Diffusion 126 5.4 Nonsteady-State Diffusion 128 5.5 Factors That Influence
Diffusion 132
5.6 Diffusion in Semiconducting Materials 137
Materials of Importance—Aluminum for Integrated Circuit Interconnects 140 5.7 Other Diffusion Paths 142
Summary 142
Equation Summary 143
Processing/Structure/Properties/Performance Summary 144
Important Terms and Concepts 144 References 144
Questions and Problems 145 Design Problems 148
6. Mechanical Properties of Metals 150
Learning Objectives 151 6.1 Introduction 151 6.2 Concepts of Stress and
Strain 152
ELASTICDEFORMATION 156
6.3 Stress–Strain Behavior 156 6.4 Anelasticity 159
6.5 Elastic Properties of Materials 160
PLASTICDEFORMATION 162
6.6 Tensile Properties 162 6.7 True Stress and Strain 170
6.8 Elastic Recovery After Plastic Deformation 173
6.9 Compressive, Shear, and Torsional Deformations 173
6.10 Hardness 174
PROPERTYVARIABILITY ANDDESIGN/SAFETY
FACTORS 180
6.11 Variability of Material Properties 180 6.12 Design/Safety Factors 182
Summary 184
Equation Summary 186
Processing/Structure/Properties/Performance Summary 187
Important Terms and Concepts 188 References 188
Questions and Problems 188 Design Problems 195
7. Dislocations and Strengthening
Mechanisms 197
Learning Objectives 198 7.1 Introduction 198
DISLOCATIONS ANDPLASTIC
DEFORMATION 199
7.2 Basic Concepts 199
7.3 Characteristics of Dislocations 201 7.4 Slip Systems 202
7.5 Slip in Single Crystals 204
7.6 Plastic Deformation of Polycrystalline Materials 208
7.7 Deformation by Twinning 210
MECHANISMS OFSTRENGTHENING IN
METALS 211
7.8 Strengthening by Grain Size Reduction 212
7.9 Solid-Solution Strengthening 213 7.10 Strain Hardening 215
RECOVERY, RECRYSTALLIZATION, ANDGRAIN
GROWTH 218
7.11 Recovery 219 7.12 Recrystallization 219 7.13 Grain Growth 224
Summary 225
Equation Summary 228
Processing/Structure/Properties/Performance Summary 228
Important Terms and Concepts 229 References 229
Questions and Problems 229 Design Problems 233
8.2 Fundamentals of Fracture 236 8.3 Ductile Fracture 236
8.4 Brittle Fracture 239
8.5 Principles of Fracture Mechanics 242 8.6 Fracture Toughness Testing 250
FATIGUE 255
8.7 Cyclic Stresses 255 8.8 The S–N Curve 257
8.9 Crack Initiation and Propagation 259 8.10 Factors That Affect Fatigue Life 262 8.11 Environmental Effects 264
CREEP 265
8.12 Generalized Creep Behavior 265 8.13 Stress and Temperature Effects 266 8.14 Data Extrapolation Methods 268 8.15 Alloys for High-Temperature Use 269
Summary 270
Equation Summary 273
Important Terms and Concepts 274 References 275
Questions and Problems 275 Design Problems 279
9. Phase Diagrams 281
Learning Objectives 282 9.1 Introduction 282
DEFINITIONS ANDBASICCONCEPTS 283
9.2 Solubility Limit 283 9.3 Phases 284
9.4 Microstructure 284 9.5 Phase Equilibria 285
9.6 One-Component (or Unary) Phase Diagrams 286
BINARYPHASEDIAGRAMS 287
9.7 Binary Isomorphous Systems 287 9.8 Interpretation of Phase
Diagrams 289
9.9 Development of Microstructure in Isomorphous Alloys 294
9.10 Mechanical Properties of Isomorphous Alloys 297
9.11 Binary Eutectic Systems 298 Materials of Importance—Lead-Free Solders 304
9.12 Development of Microstructure in Eutectic Alloys 305
9.13 Equilibrium Diagrams Having Intermediate Phases or Compounds 311 9.14 Eutectoid and Peritectic
Reactions 313
9.15 Congruent Phase Transformations 315 9.16 Ceramic and Ternary Phase
Diagrams 316
9.17 The Gibbs Phase Rule 316
THEIRON–CARBONSYSTEM 319
9.18 The Iron–Iron Carbide (Fe–Fe3C) Phase
Diagram 319
9.19 Development of Microstructure in Iron–Carbon Alloys 322
9.20 The Influence of Other Alloying Elements 330
Summary 331
Equation Summary 333
Processing/Structure/Properties/Performance Summary 334
Important Terms and Concepts 335 References 335
Questions and Problems 335
10. Phase Transformations: Development of Microstructure and Alteration of
Mechanical Properties 342
Learning Objectives 343 10.1 Introduction 343
PHASETRANSFORMATIONS 344
10.2 Basic Concepts 344 10.3 The Kinetics of Phase
Transformations 344
10.4 Metastable Versus Equilibrium States 355
MICROSTRUCTURAL ANDPROPERTYCHANGES IN
IRON–CARBONALLOYS 356
10.5 Isothermal Transformation Diagrams 356
10.6 Continuous Cooling Transformation Diagrams 367
10.7 Mechanical Behavior of Iron–Carbon Alloys 370
10.8 Tempered Martensite 375
10.9 Review of Phase Transformations and Mechanical Properties for Iron–Carbon Alloys 378
xvi • Contents
Materials of Importance—Shape-Memory Alloys 379
Summary 381
Equation Summary 383
Processing/Structure/Properties/Performance Summary 384
Important Terms and Concepts 385 References 385
Questions and Problems 385 Design Problems 390
11. Applications and Processing of Metal
Alloys 391
Learning Objectives 392 11.1 Introduction 392
TYPES OFMETALALLOYS 393
11.2 Ferrous Alloys 393 11.3 Nonferrous Alloys 406
Materials of Importance—Metal Alloys Used for Euro Coins 416
FABRICATION OFMETALS 417
11.4 Forming Operations 417 11.5 Casting 419
11.6 Miscellaneous Techniques 420
THERMALPROCESSING OFMETALS 422
11.7 Annealing Processes 422 11.8 Heat Treatment of Steels 425 11.9 Precipitation Hardening 436
Summary 442
Processing/Structure/Properties/Performance Summary 444
Important Terms and Concepts 444 References 447
Questions and Problems 447 Design Problems 449
12. Structures and Properties of
Ceramics 451
Learning Objectives 452 12.1 Introduction 452
CERAMICSTRUCTURES 453
12.2 Crystal Structures 453 12.3 Silicate Ceramics 464 12.4 Carbon 468
Materials of Importance—Carbon Nanotubes 471
12.5 Imperfections in Ceramics 472 12.6 Diffusion in Ionic Materials 476 12.7 Ceramic Phase Diagrams 476
MECHANICALPROPERTIES 480
12.8 Brittle Fracture of Ceramics 480 12.9 Stress–Strain Behavior 485 12.10 Mechanisms of Plastic
Deformation 487
12.11 Miscellaneous Mechanical Considerations 489 Summary 491
Equation Summary 494
Processing/Structure/Properties/Performance Summary 494
Important Terms and Concepts 495 References 495
Questions and Problems 495 Design Problems 500
13. Applications and Processing of
Ceramics 501
Learning Objectives 502 13.1 Introduction 502
TYPES ANDAPPLICATIONS OFCERAMICS 503
13.2 Glasses 503
13.3 Glass-Ceramics 503 13.4 Clay Products 505 13.5 Refractories 505 13.6 Abrasives 507 13.7 Cements 508
13.8 Advanced Ceramics 509
Materials of Importance—Piezoelectric Ceramics 512
FABRICATION ANDPROCESSING OF
CERAMICS 512
13.9 Fabrication and Processing of Glasses and Glass-Ceramics 513
13.10 Fabrication and Processing of Clay Products 518
13.11 Powder Pressing 523 13.12 Tape Casting 525
Summary 526
Processing/Structure/Properties/Performance Summary 528
Important Terms and Concepts 529 References 530
Questions and Problems 530 Design Problem 531
14. Polymer Structures 532
Learning Objectives 533 14.1 Introduction 533
14.2 Hydrocarbon Molecules 534
Contents • xvii
14.3 Polymer Molecules 535 14.4 The Chemistry of Polymer
Molecules 537
14.5 Molecular Weight 541 14.6 Molecular Shape 544 14.7 Molecular Structure 545 14.8 Molecular Configurations 547 14.9 Thermoplastic and Thermosetting
Polymers 550 14.10 Copolymers 551
14.11 Polymer Crystallinity 552 14.12 Polymer Crystals 556 14.13 Defects in Polymers 558
14.14 Diffusion in Polymeric Materials 559 Summary 561
Equation Summary 563
Processing/Structure/Properties/Performance Summary 564
Important Terms and Concepts 565 References 565
Questions and Problems 565
15. Characteristics, Applications, and
Processing of Polymers 569
Learning Objectives 570 15.1 Introduction 570
MECHANICALBEHAVIOR OFPOLYMERS 570
15.2 Stress–Strain Behavior 570 15.3 Macroscopic Deformation 573 15.4 Viscoelastic Deformation 574 15.5 Fracture of Polymers 578 15.6 Miscellaneous Mechanical
Characteristics 580
MECHANISMS OFDEFORMATION AND FOR
STRENGTHENING OFPOLYMERS 581
15.7 Deformation of Semicrystalline Polymers 581
15.8 Factors That Influence the Mechanical Properties of Semicrystalline
Polymers 582
Materials of Importance—Shrink-Wrap Polymer Films 587
15.9 Deformation of Elastomers 588
CRYSTALLIZATION, MELTING, ANDGLASS
TRANSITIONPHENOMENA INPOLYMERS 590
15.10 Crystallization 590 15.11 Melting 592
15.12 The Glass Transition 592 15.13 Melting and Glass Transition
Temperatures 592
15.14 Factors That Influence Melting and Glass Transition Temperatures 594
POLYMERTYPES 596
15.15 Plastics 596
Materials of Importance—Phenolic Billiard Balls 598
15.16 Elastomers 599 15.17 Fibers 601
15.18 Miscellaneous Applications 601 15.19 Advanced Polymeric Materials 603
POLYMERSYNTHESIS ANDPROCESSING 607
15.20 Polymerization 607 15.21 Polymer Additives 610
15.22 Forming Techniques for Plastics 611 15.23 Fabrication of Elastomers 614 15.24 Fabrication of Fibers and Films 614
Summary 616
Equation Summary 619
Processing/Structure/Properties/Performance Summary 619
Important Terms and Concepts 620 References 620
Questions and Problems 621 Design Questions 625
16. Composites 626
Learning Objectives 627 16.1 Introduction 627
PARTICLE-REINFORCEDCOMPOSITES 629
16.2 Large-Particle Composites 630
16.3 Dispersion-Strengthened Composites 634
FIBER-REINFORCEDCOMPOSITES 634
16.4 Influence of Fiber Length 634 16.5 Influence of Fiber Orientation and
Concentration 636 16.6 The Fiber Phase 645 16.7 The Matrix Phase 646
16.8 Polymer-Matrix Composites 647 16.9 Metal-Matrix Composites 653 16.10 Ceramic-Matrix Composites 655 16.11 Carbon–Carbon Composites 656 16.12 Hybrid Composites 657
16.13 Processing of Fiber-Reinforced Composites 657
STRUCTURALCOMPOSITES 660
16.14 Laminar Composites 660 16.15 Sandwich Panels 661
Materials of Importance—Nanocomposites in Tennis Balls 662
xviii • Contents
Summary 663
Equation Summary 666
Important Terms and Concepts 667 References 667
Questions and Problems 668 Design Problems 671
17. Corrosion and Degradation of
Materials 673
Learning Objectives 674 17.1 Introduction 674
CORROSION OFMETALS 675
17.2 Electrochemical Considerations 675 17.3 Corrosion Rates 682
17.4 Prediction of Corrosion Rates 683 17.5 Passivity 690
17.6 Environmental Effects 692 17.7 Forms of Corrosion 692 17.8 Corrosion Environments 700 17.9 Corrosion Prevention 701 17.10 Oxidation 703
CORROSION OFCERAMICMATERIALS 706
DEGRADATION OFPOLYMERS 707
17.11 Swelling and Dissolution 707 17.12 Bond Rupture 709
17.13 Weathering 710 Summary 711
Equation Summary 713
Important Terms and Concepts 714 References 715
Questions and Problems 715 Design Problems 718
18. Electrical Properties 719
Learning Objectives 720 18.1 Introduction 720
ELECTRICALCONDUCTION 721
18.2 Ohm’s Law 721
18.3 Electrical Conductivity 721
18.4 Electronic and Ionic Conduction 722 18.5 Energy Band Structures in Solids 722 18.6 Conduction in Terms of Band and Atomic
Bonding Models 725 18.7 Electron Mobility 727
18.8 Electrical Resistivity of Metals 728 18.9 Electrical Characteristics of Commercial
Alloys 731
Materials of Importance—Aluminum Electrical Wires 731
SEMICONDUCTIVITY 733
18.10 Intrinsic Semiconduction 733 18.11 Extrinsic Semiconduction 736
18.12 The Temperature Dependence of Carrier Concentration 740
18.13 Factors That Affect Carrier Mobility 742
18.14 The Hall Effect 746
18.15 Semiconductor Devices 748
ELECTRICALCONDUCTION INIONICCERAMICS
AND INPOLYMERS 754
18.16 Conduction in Ionic Materials 755 18.17 Electrical Properties of Polymers 756
DIELECTRICBEHAVIOR 757
18.18 Capacitance 757
18.19 Field Vectors and Polarization 759 18.20 Types of Polarization 762
18.21 Frequency Dependence of the Dielectric Constant 764
18.22 Dielectric Strength 765 18.23 Dielectric Materials 765
OTHERELECTRICALCHARACTERISTICS OF
MATERIALS 765
Important Terms and Concepts 773 References 774
Questions and Problems 774 Design Problems 779
19. Thermal Properties 781
Learning Objectives 782 19.1 Introduction 782 19.2 Heat Capacity 782 19.3 Thermal Expansion 785
Materials of Importance—Invar and Other Low-Expansion Alloys 788
19.4 Thermal Conductivity 789 19.5 Thermal Stresses 792
Summary 794
Equation Summary 795
Important Terms and Concepts 796 References 796
Questions and Problems 796 Design Problems 798
Contents • xix
20. Magnetic Properties 800
Learning Objectives 801 20.1 Introduction 801 20.2 Basic Concepts 801
20.3 Diamagnetism and Paramagnetism 805 20.4 Ferromagnetism 807
20.5 Antiferromagnetism and Ferrimagnetism 809 20.6 The Influence of Temperature on
Magnetic Behavior 813 20.7 Domains and Hysteresis 814 20.8 Magnetic Anisotropy 818 20.9 Soft Magnetic Materials 819
Materials of Importance—An Iron–Silicon Alloy That Is Used in Transformer
Cores 821
20.10 Hard Magnetic Materials 822 20.11 Magnetic Storage 825 20.12 Superconductivity 828
Summary 832
Equation Summary 834
Important Terms and Concepts 835 References 835
Questions and Problems 835 Design Problems 839
21. Optical Properties 840
Learning Objectives 841 21.1 Introduction 841
BASICCONCEPTS 841
21.2 Electromagnetic Radiation 841 21.3 Light Interactions with Solids 843 21.4 Atomic and Electronic Interactions 844
OPTICALPROPERTIES OFMETALS 845
OPTICALPROPERTIES OFNONMETALS 846
21.5 Refraction 846 21.6 Reflection 848 21.7 Absorption 849 21.8 Transmission 852 21.9 Color 853
21.10 Opacity and Translucency in Insulators 854
APPLICATIONS OFOPTICALPHENOMENA 855
21.11 Luminescence 855
Materials of Importance—Light-Emitting Diodes 856
21.12 Photoconductivity 858 21.13 Lasers 858
21.14 Optical Fibers in Communications 863 Summary 865
Equation Summary 868
Important Terms and Concepts 869 References 869
Questions and Problems 869 Design Problem 871
22. Economic, Environmental, and Societal Issues in Materials
Science and Engineering 872
Learning Objectives 873 22.1 Introduction 873
ECONOMICCONSIDERATIONS 873
22.2 Component Design 874 22.3 Materials 874
22.4 Manufacturing Techniques 875
ENVIRONMENTAL ANDSOCIETAL
CONSIDERATIONS 875
22.5 Recycling Issues in Materials Science and Engineering 878
Materials of Importance—Biodegradable and Biorenewable Polymers/
Plastics 881
Summary 884
References 884 Design Questions 885
Appendix A The International System of Units (SI) A1
xx • Contents
Appendix B Properties of Selected Engineering Materials A3
B.1 Density A3
B.2 Modulus of Elasticity A6 B.3 Poisson’s Ratio A10 B.4 Strength and Ductility A11
B.5 Plane Strain Fracture Toughness A16 B.6 Linear Coefficient of Thermal
Expansion A17
B.7 Thermal Conductivity A21 B.8 Specific Heat A24
B.9 Electrical Resistivity A26 B.10 Metal Alloy Compositions A29
Appendix C Costs and Relative Costs for Selected Engineering Materials A31
Appendix D Repeat Unit Structures for Common Polymers A36
Appendix E Glass Transition and Melting Temperatures for Common Polymeric Materials A40
Mechanical Engineering Online Support Module
Biomaterials Online Support Module
Glossary G1
Answers to Selected Problems S0
T
he number of the section in which a symbol is introduced or explained is given in parentheses.List of Symbols
A⫽area
Å⫽angstrom unit Ai⫽atomic weight of
element i (2.2)
APF⫽atomic packing factor (3.4) a⫽lattice parameter: unit cell
x-axial length (3.4)
a⫽crack length of a surface crack (8.5)
at% ⫽atom percent (4.4)
B⫽magnetic flux density (induc-tion) (20.2)
Br⫽ magnetic remanence (20.7) BCC ⫽body-centered cubic crystal
structure (3.4)
b⫽lattice parameter: unit cell y-axial length (3.7)
b⫽Burgers vector (4.5) C⫽capacitance (18.18)
Ci⫽concentration (composition) of component i in wt% (4.4) ⫽concentration (composition) of component i in at% (4.4) , Cp⫽heat capacity at constant
volume, pressure (19.2) CPR⫽corrosion penetration rate
(17.3)
CVN⫽Charpy V-notch (8.6) %CW⫽percent cold work (7.10)
c⫽lattice parameter: unit cell z-axial length (3.7)
c⫽velocity of electromagnetic radiation in a vacuum (21.2) D ⫽diffusion coefficient (5.3) Cy
C¿ i
D ⫽dielectric displacement (18.19) DP ⫽degree of polymerization
(14.5) d⫽diameter
d⫽average grain diameter (7.8) dhkl⫽interplanar spacing for planes of
Miller indices h, k, and l (3.16) E⫽energy (2.5)
E⫽modulus of elasticity or Young’s modulus (6.3)
e ⫽electric field intensity (18.3)
Ef⫽Fermi energy (18.5) Eg⫽band gap energy (18.6) Er(t)⫽relaxation modulus (15.4) %EL⫽ductility, in percent elongation
(6.6)
e⫽electric charge per electron (18.7)
⫽electron (17.2)
erf⫽Gaussian error function (5.4) exp⫽e, the base for natural
logarithms
F⫽force, interatomic or mechanical (2.5, 6.3)
f⫽Faraday constant (17.2)
FCC⫽face-centered cubic crystal structure (3.4)
G ⫽shear modulus (6.3)
H ⫽magnetic field strength (20.2) Hc⫽magnetic coercivity (20.7) HB⫽Brinell hardness (6.10)
HCP ⫽hexagonal close-packed crystal structure (3.4)
e⫺
HK⫽Knoop hardness (6.10) HRB, HRF⫽Rockwell hardness: B and F
scales (6.10)
HR15N, HR45W⫽superficial Rockwell hardness: 15N and 45W scales (6.10) HV⫽Vickers hardness (6.10)
h⫽Planck’s constant (21.2) (hkl)⫽Miller indices for a
crystallo-graphic plane (3.10) I⫽electric current (18.2) I⫽intensity of electromagnetic
radiation (21.3) i⫽current density (17.3) iC⫽corrosion current density
(17.4)
J⫽diffusion flux (5.3)
J⫽electric current density (18.3) Kc⫽fracture toughness (8.5) KIc⫽plane strain fracture toughness
for mode I crack surface dis-placement (8.5)
k⫽Boltzmann’s constant (4.2) k⫽thermal conductivity (19.4)
l⫽length
lc⫽critical fiber length (16.4) ln⫽natural logarithm
log⫽logarithm taken to base 10 M⫽magnetization (20.2)
⫽polymer number-average molecular weight (14.5) ⫽polymer weight-average
molecular weight (14.5) mol%⫽mole percent
N⫽number of fatigue cycles (8.8) NA⫽Avogadro’s number (3.5)
Nf⫽fatigue life (8.8)
n⫽principal quantum number (2.3) n⫽number of atoms per unit cell
(3.5)
n⫽strain-hardening exponent (6.7) n⫽number of electrons in an
electrochemical reaction (17.2) n⫽number of conducting
elec-trons per cubic meter (18.7) n⫽index of refraction (21.5) Mw
Mn
xxii • List of Symbols
n⬘ ⫽for ceramics, the number of formula units per unit cell (12.2)
ni⫽intrinsic carrier (electron and hole) concentration (18.10) P⫽dielectric polarization (18.19) P–B ratio ⫽Pilling–Bedworth ratio (17.10)
p⫽number of holes per cubic meter (18.10)
Q ⫽activation energy
Q ⫽magnitude of charge stored (18.18)
R⫽atomic radius (3.4) R⫽gas constant
%RA⫽ductility, in percent reduction in area (6.6)
r⫽interatomic distance (2.5) r⫽reaction rate (17.3)
rA, rC⫽anion and cation ionic radii
(12.2)
S ⫽fatigue stress amplitude (8.8) SEM⫽scanning electron microscopy
or microscope T⫽temperature
Tc⫽Curie temperature (20.6) TC⫽superconducting critical
temperature (20.12)
Tg⫽glass transition temperature (13.9, 15.12)
Tm⫽melting temperature TEM⫽transmission electron
microscopy or microscope TS ⫽tensile strength (6.6)
t⫽time
tr⫽rupture lifetime (8.12) Ur⫽modulus of resilience (6.6) [u w]⫽indices for a crystallographic
direction (3.9)
V⫽ electrical potential difference (voltage) (17.2, 18.2)
VC⫽ unit cell volume (3.4) VC⫽corrosion potential (17.4) VH⫽Hall voltage (18.14)
Vi⫽volume fraction of phase i (9.8) ⫽velocity
vol%⫽volume percent y
y
Wi⫽mass fraction of phase i (9.8) wt%⫽weight percent (4.4)
x⫽length
x⫽space coordinate
Y⫽dimensionless parameter or function in fracture toughness expression (8.5)
y⫽space coordinate z⫽space coordinate
␣⫽lattice parameter: unit cell y–z interaxial angle (3.7)
␣,,␥⫽phase designations
␣l⫽linear coefficient of thermal expansion (19.3)
⫽lattice parameter: unit cell x–z interaxial angle (3.7)
␥⫽lattice parameter: unit cell x–y interaxial angle (3.7)
␥⫽shear strain (6.2)
⌬ ⫽precedes the symbol of a parameter to denote finite change
⫽engineering strain (6.2) ⫽dielectric permittivity (18.18) ⫽dielectric constant or relative
permittivity (18.18)
⫽steady-state creep rate (8.12) ⫽true strain (6.7)
⫽viscosity (12.10)
⫽overvoltage (17.4)
⫽Bragg diffraction angle (3.16)
D⫽Debye temperature (19.2)
⫽wavelength of electromagnetic radiation (3.16)
⫽magnetic permeability (20.2)
B⫽Bohr magneton (20.2)
r⫽relative magnetic permeability (20.2)
e⫽electron mobility (18.7)
h⫽hole mobility (18.10) ⫽Poisson’s ratio (6.5)
⫽frequency of electromagnetic radiation (21.2)
List of Symbols • xxiii
⫽electrical resistivity (18.2)
t⫽radius of curvature at the tip of a crack (8.5)
⫽engineering stress, tensile or compressive (6.2)
⫽electrical conductivity (18.3)
*⫽longitudinal strength (compos-ite) (16.5)
c⫽critical stress for crack propa-gation (8.5)
fs⫽flexural strength (12.9)
m⫽maximum stress (8.5)
c⫽fiber–matrix bond
strength/matrix shear yield strength (16.4)
crss⫽critical resolved shear stress
(7.5)
⫽magnetic susceptibility (20.2)
S
UBSCRIPTSc⫽composite
cd⫽discontinuous fibrous composite
cl⫽longitudinal direction (aligned fibrous composite)
ct⫽transverse direction (aligned fibrous composite) 0⫽at equilibrium 0⫽in a vacuum xm
• 1
C h a p t e r
1
Introduction
A
familiar item that is fabricated from three different material types is the beverage container. Beverages are marketed in aluminum (metal) cans (top), glass (ceramic) bottles (center), and plastic (polymer) bottles (bottom). (Permission to use these photographs was granted by the Coca-Cola Company. Coca-Cola, Coca-Cola Classic, the Contour Bottle design and the Dynamic Ribbon are registered trademarks of The Coca-Cola Company and used with its express permission. Soda being poured from a glass: © blickwinkel/Alamy.)1.1 HISTORICAL PERSPECTIVE
Materials are probably more deep-seated in our culture than most of us realize. Transportation, housing, clothing, communication, recreation, and food production— virtually every segment of our everyday lives is influenced to one degree or another by materials. Historically, the development and advancement of societies have been intimately tied to the members’ ability to produce and manipulate materials to fill their needs. In fact, early civilizations have been designated by the level of their materials development (Stone Age, Bronze Age, Iron Age).1
The earliest humans had access to only a very limited number of materials, those that occur naturally: stone, wood, clay, skins, and so on. With time they dis-covered techniques for producing materials that had properties superior to those of the natural ones; these new materials included pottery and various metals. Fur-thermore, it was discovered that the properties of a material could be altered by heat treatments and by the addition of other substances. At this point, materials uti-lization was totally a selection process that involved deciding from a given, rather limited set of materials the one best suited for an application by virtue of its char-acteristics. It was not until relatively recent times that scientists came to understand the relationships between the structural elements of materials and their properties. This knowledge, acquired over approximately the past 100 years, has empowered them to fashion, to a large degree, the characteristics of materials. Thus, tens of thou-sands of different materials have evolved with rather specialized characteristics that meet the needs of our modern and complex society; these include metals, plastics, glasses, and fibers.
The development of many technologies that make our existence so com-fortable has been intimately associated with the accessibility of suitable materials. An advancement in the understanding of a material type is often the fore-runner to the stepwise progression of a technology. For example, automobiles would not have been possible without the availability of inexpensive steel or some other comparable substitute. In our contemporary era, sophisticated elec-tronic devices rely on components that are made from what are called semicon-ducting materials.
L e a r n i n g O b j e c t i v e s
After studying this chapter you should be able to do the following: 1. List six different property classifications of
materials that determine their applicability. 2. Cite the four components that are involved in
the design, production, and utilization of materials, and briefly describe the interrelation-ships between these components.
3. Cite three criteria that are important in the materials selection process.
4. (a) List the three primary classifications of solid materials, and then cite the distinctive chemical feature of each.
(b) Note the four types of advanced materials and, for each, its distinctive feature(s). 5. (a) Briefly define “smart material/system.”
(b) Briefly explain the concept of “nanotech-nology” as it applies to materials.
1The approximate dates for the beginnings of the Stone, Bronze, and Iron Ages were 2.5 million BC, 3500 BC, and 1000 BC, respectively.
2 •
1.2 MATERIALS SCIENCE AND ENGINEERING
Sometimes it is useful to subdivide the discipline of materials science and engi-neering into materials science and materials engiengi-neering subdisciplines. Strictly speaking, materials science involves investigating the relationships that exist be-tween the structures and properties of materials. In contrast, materials engineering is, on the basis of these structure–property correlations, designing or engineering the structure of a material to produce a predetermined set of properties.2From a functional perspective, the role of a materials scientist is to develop or synthesize new materials, whereas a materials engineer is called upon to create new products or systems using existing materials, and/or to develop techniques for processing materials. Most graduates in materials programs are trained to be both materials scientists and materials engineers.
Structure is at this point a nebulous term that deserves some explanation. In brief, the structure of a material usually relates to the arrangement of its internal components. Subatomic structure involves electrons within the individual atoms and interactions with their nuclei. On an atomic level, structure encompasses the or-ganization of atoms or molecules relative to one another. The next larger structural realm, which contains large groups of atoms that are normally agglomerated to-gether, is termed microscopic, meaning that which is subject to direct observation using some type of microscope. Finally, structural elements that may be viewed with the naked eye are termed macroscopic.
The notion of property deserves elaboration. While in service use, all materials are exposed to external stimuli that evoke some type of response. For example, a specimen subjected to forces will experience deformation, or a polished metal surface will reflect light. A property is a material trait in terms of the kind and magnitude of response to a specific imposed stimulus. Generally, definitions of properties are made independent of material shape and size.
Virtually all important properties of solid materials may be grouped into six different categories: mechanical, electrical, thermal, magnetic, optical, and deterio-rative. For each there is a characteristic type of stimulus capable of provoking dif-ferent responses. Mechanical properties relate deformation to an applied load or force; examples include elastic modulus (stiffness), strength, and toughness. For elec-trical properties, such as elecelec-trical conductivity and dielectric constant, the stimu-lus is an electric field. The thermal behavior of solids can be represented in terms of heat capacity and thermal conductivity. Magnetic properties demonstrate the re-sponse of a material to the application of a magnetic field. For optical properties, the stimulus is electromagnetic or light radiation; index of refraction and reflectiv-ity are representative optical properties. Finally, deteriorative characteristics relate to the chemical reactivity of materials. The chapters that follow discuss properties that fall within each of these six classifications.
In addition to structure and properties, two other important components are involved in the science and engineering of materials—namely, processing and per-formance. With regard to the relationships of these four components, the structure of a material will depend on how it is processed. Furthermore, a material’s per-formance will be a function of its properties. Thus, the interrelationship between processing, structure, properties, and performance is as depicted in the schematic
1.2 Materials Science and Engineering • 3
2Throughout this text we draw attention to the relationships between material properties and structural elements.
4 • Chapter 1 / Introduction
illustration shown in Figure 1.1. Throughout this text we draw attention to the relationships among these four components in terms of the design, production, and utilization of materials.
We now present an example of these processing-structure-properties-performance principles with Figure 1.2, a photograph showing three thin disk specimens placed over some printed matter. It is obvious that the optical properties (i.e., the light mittance) of each of the three materials are different; the one on the left is trans-parent (i.e., virtually all of the reflected light passes through it), whereas the disks in the center and on the right are, respectively, translucent and opaque. All of these spec-imens are of the same material, aluminum oxide, but the leftmost one is what we call a single crystal—that is, has a high degree of perfection—which gives rise to its trans-parency. The center one is composed of numerous and very small single crystals that are all connected; the boundaries between these small crystals scatter a portion of the light reflected from the printed page, which makes this material optically translucent. Finally, the specimen on the right is composed not only of many small, interconnected crystals, but also of a large number of very small pores or void spaces. These pores also effectively scatter the reflected light and render this material opaque.
Thus, the structures of these three specimens are different in terms of crystal boundaries and pores, which affect the optical transmittance properties. Further-more, each material was produced using a different processing technique. And, of course, if optical transmittance is an important parameter relative to the ultimate in-service application, the performance of each material will be different.
Figure 1.1 The four components of the discipline of materials science and engineering and their interrelationship.
Processing Structure Properties Performance
Figure 1.2 Three thin disk specimens of aluminum oxide that have been placed over a printed page in order to demonstrate their differences in light-transmittance characteristics. The disk on the left is transparent (i.e., virtually all light that is reflected from the page passes through it), whereas the one in the center is translucent (meaning that some of this reflected light is transmitted through the disk). The disk on the right is opaque—that is, none of the light passes through it. These differences in optical properties are a consequence of differences in structure of these materials, which have resulted from the way the materials were processed. (Specimen preparation, P. A. Lessing; photography by S. Tanner.)
