Materials Science and Engineering: An Introduction 9th Edition PDF

MATERIALS SCIENCE and ENGINEERING An Introduction 9E William D. Callister, Jr. David G. Rethwisch Characteristics of Selected Elements Atomic Density of Crystal Atomic Ionic Most...

MATERIALS SCIENCE and ENGINEERING An Introduction 9E William D. Callister, Jr. David G. Rethwisch Characteristics of Selected Elements Atomic Density of Crystal Atomic Ionic Most Melting Atomic Weight Solid, 20ⴗC Structure, Radius Radius Common Point Element Symbol Number (amu) (g/cm3) 20ⴗC (nm) (nm) Valence (ⴗC) 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 ⫻ 10 23 6.022 ⫻ 1023 molecules/mol molecules/mol Boltzmann’s constant k 1.38 ⫻ 10⫺23 J/atom # K 1.38 ⫻ 10⫺16 erg/atom # K 8.62 ⫻ 10⫺5 eV/atom # K Bohr magneton mB 9.27 ⫻ 10⫺24 A # m2 9.27 ⫻ 10⫺21 erg/gaussa Electron charge e 1.602 ⫻ 10⫺19 C 4.8 ⫻ 10⫺10 statcoulb Electron mass — 9.11 ⫻ 10⫺31 kg 9.11 ⫻ 10⫺28 g Gas constant R 8.31 J/mol # K 1.987 cal/mol # K Permeability of a vacuum m0 1.257 ⫻ 10⫺6 henry/m unitya Permittivity of a vacuum ⑀0 8.85 ⫻ 10⫺12 farad/m unityb Planck’s constant h 6.63 ⫻ 10⫺34 J # s 6.63 ⫻ 10⫺27 erg # s 4.13 ⫻ 10⫺15 eV # s Velocity of light in a vacuum c 3 ⫻ 108 m/s 3 ⫻ 1010 cm/s a In cgs-emu units. b In cgs-esu units. Unit Abbreviations A ⫽ ampere in. ⫽ inch N ⫽ newton Å ⫽ angstrom J⫽ joule nm ⫽ nanometer Btu ⫽ British thermal unit K⫽ degrees Kelvin P ⫽ poise C ⫽ Coulomb kg ⫽ kilogram Pa ⫽ Pascal ⬚C ⫽ 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) ⬚F ⫽ degrees Fahrenheit mm ⫽ millimeter W ⫽ watt ft ⫽ foot mol ⫽ mole psi ⫽ pounds per square g ⫽ gram MPa ⫽ megapascal inch SI Multiple and Submultiple Prefixes Factor by Which Multiplied Prefix Symbol 9 10 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 a Avoided when possible. WileyPLUS is a research-based online environment for effective teaching and learning. WileyPLUS builds students’ confidence because it takes the guesswork out of studying by providing students with a clear roadmap: what to do how to do it if they did it right It offers interactive resources along with a complete digital textbook that help students learn more. With WileyPLUS, students take more initiative so you’ll have greater impact on their achievement in the classroom and beyond. Now available for For more information, visit www.wileyplus.com  ALL THE HELP, RESOURCES, AND PERSONAL SUPPORT YOU AND YOUR STUDENTS NEED! www.wileyplus.com/resources Student Partner Program 2-Minute Tutorials and all Student support from an Collaborate with your colleagues, of the resources you and your experienced student user find a mentor, attend virtual and live students need to get started events, and view resources www.WhereFacultyConnect.com Quick Start © Courtney Keating/iStockphoto Pre-loaded, ready-to-use Technical Support 24/7 FAQs, online chat, Your WileyPLUS Account Manager, assignments and presentations and phone support providing personal training created by subject matter experts www.wileyplus.com/support and support  9th Edition Materials 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 Front Cover: Depiction of a unit cell for iron carbide (Fe3C) from three different perspectives. Brown and blue spheres represent iron and carbon atoms, respectively. Back Cover: Three representations of the unit cell for body-centered cubic iron (a-ferrite); each unit cell contains an interstitial carbon atom. VICE PRESIDENT AND EXECUTIVE PUBLISHER Donald Fowley EXECUTIVE EDITOR Daniel Sayre EDITORIAL PROGRAM ASSISTANT Jessica Knecht SENIOR CONTENT MANAGER Kevin Holm PRODUCTION EDITOR James Metzger EXECUTIVE MARKETING MANAGER Christopher Ruel DESIGN DIRECTOR Harry Nolan SENIOR DESIGNER Madelyn Lesure SENIOR PHOTO EDITOR MaryAnn Price COVER ART Roy Wiemann and William D. Callister, Jr. This book was set in 9.5/11.5 Times Ten LT Std by Aptara, Inc., and printed and bound by Quad Graphics/Versailles. The cover was printed by Quad Graphics/Versailles. This book is printed on acid-free paper. q Copyright © 2014, 2010, 2007, 2003, 2000 John Wiley & Sons, Inc. All rights reserved. No part of this publication 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. ISBN: 978-1-118-32457-8 Wiley Binder Version ISBN: 978-1-118-47770-0 Printed in the United States of America 10 9 8 7 6 5 4 3 2 1  Dedicated to Bill Stenquist, editor and friend  Preface I n this ninth edition we have retained the objectives and approaches for teaching materials science and engineering that were presented in previous editions. The first, and primary, objective is to present the basic fundamentals on a level appropriate for university/college students who have completed their freshmen calculus, chemistry, and physics courses. 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 sufficient detail and to the extent that students have the opportunity to fully understand it without having to consult other sources; in addition, in most cases, some practical relevance is provided. The fourth objective is to include features in the book that will expedite the learning process. These learning aids include the following: 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 as well as case studies that provide relevance to topic discussions “Concept Check” questions that test whether 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 students can check their work A glossary, a global list of symbols, and references to facilitate understanding of the subject matter End-of-chapter summary tables of important equations and symbols used in these equations Processing/Structure/Properties/Performance correlations and summary concept maps for four materials (steels, glass-ceramics, polymer fibers, and silicon semiconductors), which integrate important concepts from chapter to chapter Materials of Importance sections that lend relevance to topical coverage by discussing familiar and interesting materials and their applications The fifth objective is to enhance the teaching and learning process by using the newer tech- nologies that are available to most instructors and today’s engineering students. vii viii Preface New/Revised Content Several important changes have been made with this Ninth Edition. One of the most signifi- cant is the incorporation of several new sections, as well as revisions/amplifications of other sections. These include the following: Numerous new and revised example problems. In addition, all homework problems requiring computations have been refreshed. Revised, expanded, and updated tables Two new case studies: “Liberty Ship Failures” (Chapter 1) and “Use of Composites in the Boeing 787 Dreamliner” (Chapter 16) Bond hybridization in carbon (Chapter 2) Revision of discussions on crystallographic planes and directions to include the use of equations for the determination of planar and directional indices (Chapter 3) Revised discussion on determination of grain size (Chapter 4) New section on the structure of carbon fibers (Chapter 13) Revised/expanded discussions on structures, properties, and applications of the nanocarbons: fullerenes, carbon nanotubes, and graphene (Chapter 13) Revised/expanded discussion on structural composites: laminar composites and sandwich panels (Chapter 16) New section on structure, properties, and applications of nanocomposite materials (Chapter 16) Tutorial videos. In WileyPLUS, Tutorial Videos help students with their “muddiest points” in conceptual understanding and problem-solving. Exponents and logarithms. In WileyPLUS, the exponential functions and natural logarithms have been added to the Exponents and Logarithms section of the Math Skills Review. Fundamentals of Engineering homework problems and questions for most chapters. These appear at the end of Questions and Problems sections and provide students the opportunity to practice answering and solving questions and problems similar to those found on Fundamentals of Engineering examinations. Online Learning Resources—Student Companion Site at www.wiley.com/college/callister. Also found on the book’s website is a Students’ Companion page on which is posted several important instructional elements for the student that complement the text; these include the following: Answers to Concept Check questions, questions which are found in the print book. Library of Case Studies. One way to demonstrate principles of design in an engineering curriculum is via case studies: analyses of problem-solving strategies applied to real-world examples of applications/devices/failures encountered by engineers. Five case studies are provided as follows: (1) Materials Selection for a Torsionally Stressed Cylindrical Shaft; (2) Automobile Valve Spring; (3) Failure of an Automobile Rear Axle; (4) Artificial Total Hip Replacement; and (5) Chemical Protective Clothing. Mechanical Engineering (ME) Module. This module treats materials science/ engineering topics not covered in the printed text that are relevant to mechanical engineering. Extended Learning Objectives. This is 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 depth.  Preface ix Student Lecture PowerPoint® Slides. These slides (in both Adobe Acrobat® PDF and PowerPoint® formats) are virtually identical to the lecture slides provided to an instructor for use in the classroom. The student set has been designed to allow for note taking on printouts. 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. Online Resources for Instructors—Instructors Companion Site at www.wiley.com/college/callister. The Instructor Companion Site is available for instructors who have adopted this text. Please visit the website to register for access. Resources that are available include the following: All resources found on the Student Companion Site. (Except for the Student Lecture PowerPoint® Slides.) Instructor Solutions Manual. Detailed solutions for all end-of-chapter questions and problems (in both Word® and Adobe Acrobat® PDF formats). Homework Problem Correlation Guide—8th edition to 9th edition. This guide notes, for each homework problem or question (by number), whether it appeared in the eighth edition and, if so, its number in this previous edition. Virtual Materials Science and Engineering (VMSE). This web-based software package consists of interactive simulations and animations that enhance the learning of key concepts in materials science and engineering. Included in VMSE are eight modules and a materials properties/cost database. Titles of these modules are as follows: (1) Metallic Crystal Structures and Crystallography; (2) Ceramic Crystal Structures; (3) Repeat Unit and Polymer Structures; (4) Dislocations; (5) Phase Diagrams; (6) Diffusion; (7) Tensile Tests; and (8) Solid-Solution Strengthening. Image Gallery. Illustrations from the book. Instructors can use them in assignments, tests, or other exercises they create for students. Art PowerPoint Slides. Book art loaded into PowerPoints, so instructors can more easily use them to create their own PowerPoint Slides. Lecture Note PowerPoints. These slides, developed by the authors and Peter M. Anderson (The Ohio State University), follow the flow of topics in the text, and include materials taken from the text as well as other sources. Slides are available in both Adobe Acrobat® PDF and PowerPoint® formats. [Note: If an instructor doesn’t have available all fonts used by the developer, special characters may not be displayed correctly in the PowerPoint version (i.e., it is not possible to embed fonts in PowerPoints); however, in the PDF version, these characters will appear correctly.] Solutions to Case Study Problems. Solutions to Problems in the Mechanical Engineering Web Module. Suggested Course Syllabi for the Various Engineering Disciplines. Instructors may consult these syllabi for guidance in course/lecture organization and planning. Experiments and Classroom Demonstrations. Instructions and outlines for experiments and classroom demonstrations that portray phenomena and/or illustrate principles that are discussed in the book; references are also provided that give more detailed accounts of these demonstrations. x Preface WileyPLUS WileyPLUS is a research-based online environment for effective teaching and learning. WileyPLUS builds students’ confidence by taking the guesswork out of studying by providing them with a clear roadmap: what is assigned, what is required for each assign- ment, and whether assignments are done correctly. Independent research has shown that students using WileyPLUS will take more initiative so the instructor has a greater impact on their achievement in the classroom and beyond. WileyPLUS also helps students study and progress at a pace that’s right for them. Our integrated resources–available 24/7– function like a personal tutor, directly addressing each student’s demonstrated needs by providing specific problem-solving techniques. What do students receive with WileyPLUS? The complete digital textbook that saves students up to 60% of the cost of the in-print text. Navigation assistance, including links to relevant sections in the online textbook. Immediate feedback on performance and progress, 24/7. Integrated, multi-media resources—to include VMSE (Virtual Materials Science & Engineering), tutorial videos, a Math Skills Review, flashcards, and much more; these resources provide multiple study paths and encourage more active learning. What do instructors receive with WileyPLUS? The ability to effectively and efficiently personalize and manage their course. The ability to track student performance and progress, and easily identify those who are falling behind. Media-rich course materials and assessment resources including—a complete Solutions Manual, PowerPoint® Lecture Slides, Extended Learning Objectives, and much more. www.WileyPLUS.com Feedback We have a sincere interest in meeting the needs of educators and students in the materi- als science and engineering community, and therefore we solicit feedback on this edition. Comments, suggestions, and criticisms may be submitted to the authors via email at the following address: [email protected]. Acknowledgments Since we undertook 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. We express our appreciation to those who have made contributions to this edition. We are especially indebted to the following: Audrey Butler of The University of Iowa, and Bethany Smith and Stephen Krause of Arizona State University, for helping to develop material in the WileyPLUS course. Grant Head for his expert programming skills, which he used in developing the Vir- tual Materials Science and Engineering software. Eric Hellstrom and Theo Siegrist of Florida State University for their feedback and suggestions for this edition.  Preface xi In addition, we thank the many instructors who participated in the fall 2011 market- ing survey; their valuable contributions were driving forces for many of the changes and additions to this ninth edition. We are also indebted to Dan Sayre, Executive Editor, Jennifer Welter, Senior Prod- uct Designer, and Jessica Knecht, Editorial Program Assistant, for their guidance and assistance on this revision. Last, but certainly not least, we deeply and sincerely appreciate the continual en- couragement and support of our families and friends. William D. Callister, Jr. David G. Rethwisch October 2013  Contents LIST OF SYMBOLS xxi Equation Summary 46 List of Symbols 46 1. Introduction 1 Processing/Structure/Properties/Performance Summary 47 Learning Objectives 2 Important Terms and Concepts 47 1.1 Historical Perspective 2 References 47 1.2 Materials Science and Engineering 2 Questions and Problems 48 1.3 Why Study Materials Science and Fundamentals of Engineering Questions and Engineering? 4 Problems 50 Case Study—Liberty Ship Failures 5 1.4 Classification of Materials 6 Case Study—Carbonated Beverage 3. The Structure of Crystalline Solids 51 Containers 11 Learning Objectives 52 1.5 Advanced Materials 12 3.1 Introduction 52 1.6 Modern Materials’ Needs 14 1.7 Processing/Structure/Properties/ CRYSTAL STRUCTURES 52 Performance Correlations 15 3.2 Fundamental Concepts 52 Summary 17 3.3 Unit Cells 53 References 17 3.4 Metallic Crystal Structures 54 Questions 18 3.5 Density Computations 60 3.6 Polymorphism and Allotropy 60 2. Atomic Structure and Interatomic Materials of Importance—Tin (Its Bonding 19 Allotropic Transformation) 61 3.7 Crystal Systems 62 Learning Objectives 20 CRYSTALLOGRAPHIC POINTS, DIRECTIONS, AND 2.1 Introduction 20 PLANES 64 ATOMIC STRUCTURE 20 3.8 Point Coordinates 64 2.2 Fundamental Concepts 20 3.9 Crystallographic Directions 67 2.3 Electrons in Atoms 22 3.10 Crystallographic Planes 75 2.4 The Periodic Table 28 3.11 Linear and Planar Densities 81 ATOMIC BONDING IN SOLIDS 30 3.12 Close-Packed Crystal Structures 82 2.5 Bonding Forces and Energies 30 CRYSTALLINE AND NONCRYSTALLINE 2.6 Primary Interatomic Bonds 32 MATERIALS 84 2.7 Secondary Bonding or van der Waals 3.13 Single Crystals 84 Bonding 39 3.14 Polycrystalline Materials 84 Materials of Importance—Water (Its 3.15 Anisotropy 86 Volume Expansion Upon Freezing) 42 3.16 X-Ray Diffraction: Determination of 2.8 Mixed Bonding 43 Crystal Structures 87 2.9 Molecules 44 3.17 Noncrystalline Solids 92 2.10 Bonding Type-Materials Classification Summary 93 Correlations 44 Equation Summary 95 Summary 45 List of Symbols 96 xiii xiv Contents Processing/Structure/Properties/Performance 5.7 Other Diffusion Paths 158 Summary 96 Summary 158 Important Terms and Concepts 97 Equation Summary 159 References 97 List of Symbols 160 Questions and Problems 97 Processing/Structure/Properties/Performance Fundamentals of Engineering Questions and Summary 160 Problems 104 Important Terms and Concepts 162 References 162 Questions and Problems 162 4. Imperfections in Solids 105 Design Problems 166 Learning Objectives 106 Fundamentals of Engineering Questions and 4.1 Introduction 106 Problems 167 POINT DEFECTS 106 4.2 Vacancies and Self-Interstitials 106 6. Mechanical Properties of Metals 168 4.3 Impurities in Solids 108 Learning Objectives 169 4.4 Specification of Composition 111 6.1 Introduction 169 MISCELLANEOUS IMPERFECTIONS 115 6.2 Concepts of Stress and Strain 170 4.5 Dislocations—Linear Defects 115 ELASTIC DEFORMATION 174 4.6 Interfacial Defects 118 6.3 Stress–Strain Behavior 174 Materials of Importance—Catalysts (and 6.4 Anelasticity 177 Surface Defects) 121 6.5 Elastic Properties of Materials 177 4.7 Bulk or Volume Defects 122 PLASTIC DEFORMATION 180 4.8 Atomic Vibrations 122 6.6 Tensile Properties 180 MICROSCOPIC EXAMINATION 123 6.7 True Stress and Strain 187 4.9 Basic Concepts of Microscopy 123 6.8 Elastic Recovery After Plastic 4.10 Microscopic Techniques 124 Deformation 190 4.11 Grain-Size Determination 128 6.9 Compressive, Shear, and Torsional Summary 131 Deformation 191 Equation Summary 132 6.10 Hardness 191 List of Symbols 133 Processing/Structure/Properties/Performance PROPERTY VARIABILITY AND DESIGN/SAFETY Summary 134 FACTORS 197 Important Terms and Concepts 135 6.11 Variability of Material Properties 197 References 135 6.12 Design/Safety Factors 199 Questions and Problems 135 Summary 203 Design Problems 138 Equation Summary 205 Fundamentals of Engineering Questions and List of Symbols 205 Problems 139 Processing/Structure/Properties/Performance Summary 206 Important Terms and Concepts 206 5. Diffusion 140 References 207 Learning Objectives 141 Questions and Problems 207 5.1 Introduction 141 Design Problems 213 5.2 Diffusion Mechanisms 142 Fundamentals of Engineering Questions and 5.3 Fick’s First Law 143 Problems 214 5.4 Fick’s Second Law—Nonsteady-State Diffusion 145 7. Dislocations and Strengthening 5.5 Factors That Influence Diffusion 149 Mechanisms 216 5.6 Diffusion in Semiconducting Materials 154 Learning Objectives 217 Material of Importance—Aluminum for 7.1 Introduction 217 Integrated Circuit Interconnects 157 DISLOCATIONS AND PLASTIC DEFORMATION 217  Contents xv 7.2 Basic Concepts 218 Equation Summary 290 7.3 Characteristics of Dislocations 220 List of Symbols 290 7.4 Slip Systems 221 Important Terms and Concepts 291 7.5 Slip in Single Crystals 223 References 291 7.6 Plastic Deformation of Polycrystalline Questions and Problems 291 Materials 226 Design Problems 295 7.7 Deformation by Twinning 228 Fundamentals of Engineering Questions and Problems 296 MECHANISMS OF STRENGTHENING IN METALS 229 7.8 Strengthening by Grain Size Reduction 229 9. Phase Diagrams 297 7.9 Solid-Solution Strengthening 231 7.10 Strain Hardening 232 Learning Objectives 298 9.1 Introduction 298 RECOVERY, RECRYSTALLIZATION, AND GRAIN GROWTH 235 DEFINITIONS AND BASIC CONCEPTS 298 7.11 Recovery 235 9.2 Solubility Limit 299 7.12 Recrystallization 236 9.3 Phases 300 7.13 Grain Growth 240 9.4 Microstructure 300 Summary 242 9.5 Phase Equilibria 300 Equation Summary 244 9.6 One-Component (or Unary) Phase List of Symbols 244 Diagrams 301 Processing/Structure/Properties/Performance BINARY PHASE DIAGRAMS 302 Summary 245 Important Terms and Concepts 246 9.7 Binary Isomorphous Systems 303 References 246 9.8 Interpretation of Phase Diagrams 305 Questions and Problems 246 9.9 Development of Microstructure in Design Problems 250 Isomorphous Alloys 309 Fundamentals of Engineering Questions and 9.10 Mechanical Properties of Isomorphous Problems 250 Alloys 312 9.11 Binary Eutectic Systems 312 9.12 Development of Microstructure in 8. Failure 251 Eutectic Alloys 318 Materials of Importance—Lead-Free Learning Objectives 252 Solders 319 8.1 Introduction 252 9.13 Equilibrium Diagrams Having Intermediate FRACTURE 253 Phases or Compounds 325 8.2 Fundamentals of Fracture 253 9.14 Eutectoid and Peritectic Reactions 328 8.3 Ductile Fracture 253 9.15 Congruent Phase Transformations 329 8.4 Brittle Fracture 255 9.16 Ceramic and Ternary Phase 8.5 Principles of Fracture Mechanics 257 Diagrams 330 8.6 Fracture Toughness Testing 265 9.17 The Gibbs Phase Rule 330 FATIGUE 270 THE IRON–CARBON SYSTEM 333 8.7 Cyclic Stresses 270 9.18 The Iron–Iron Carbide (Fe–Fe3C) Phase 8.8 The S–N Curve 272 Diagram 333 8.9 Crack Initiation and Propagation 276 9.19 Development of Microstructure in 8.10 Factors That Affect Fatigue Life 278 Iron–Carbon Alloys 336 8.11 Environmental Effects 280 9.20 The Influence of Other Alloying CREEP 281 Elements 344 Summary 344 8.12 Generalized Creep Behavior 281 Equation Summary 346 8.13 Stress and Temperature Effects 282 List of Symbols 347 8.14 Data Extrapolation Methods 285 Processing/Structure/Properties/Performance 8.15 Alloys for High-Temperature Use 286 Summary 347 Summary 287 Important Terms and Concepts 349 xvi Contents References 349 11.5 Casting 436 Questions and Problems 349 11.6 Miscellaneous Techniques 437 Fundamentals of Engineering Questions and THERMAL PROCESSING OF METALS 439 Problems 355 11.7 Annealing Processes 439 10. Phase Transformations: Development 11.8 Heat Treatment of Steels 441 of Microstructure and Alteration of 11.9 Precipitation Hardening 451 Mechanical Properties 356 Summary 458 Processing/Structure/Properties/Performance Learning Objectives 357 Summary 460 10.1 Introduction 357 Important Terms and Concepts 460 PHASE TRANSFORMATIONS 357 References 463 Questions and Problems 463 10.2 Basic Concepts 357 Design Problems 464 10.3 The Kinetics of Phase Transformations 358 Fundamentals of Engineering Questions and 10.4 Metastable Versus Equilibrium States 369 Problems 466 MICROSTRUCTURAL AND PROPERTY CHANGES IN IRON–CARBON ALLOYS 370 12. Structures and Properties of 10.5 Isothermal Transformation Diagrams 370 Ceramics 467 10.6 Continuous-Cooling Transformation Learning Objectives 468 Diagrams 381 12.1 Introduction 468 10.7 Mechanical Behavior of Iron–Carbon Alloys 384 CERAMIC STRUCTURES 468 10.8 Tempered Martensite 388 12.2 Crystal Structures 469 10.9 Review of Phase Transformations and 12.3 Silicate Ceramics 477 Mechanical Properties for Iron–Carbon 12.4 Carbon 481 Alloys 391 12.5 Imperfections in Ceramics 482 Materials of Importance—Shape-Memory 12.6 Diffusion in Ionic Materials 486 Alloys 394 12.7 Ceramic Phase Diagrams 487 Summary 397 MECHANICAL PROPERTIES 490 Equation Summary 398 List of Symbols 399 12.8 Brittle Fracture of Ceramics 491 Processing/Structure/Properties/Performance 12.9 Stress–Strain Behavior 495 Summary 399 12.10 Mechanisms of Plastic Deformation 497 Important Terms and Concepts 401 12.11 Miscellaneous Mechanical References 402 Considerations 499 Questions and Problems 402 Summary 501 Design Problems 406 Equation Summary 503 Fundamentals of Engineering Questions and List of Symbols 503 Problems 406 Processing/Structure/Properties/Performance Summary 503 11. Applications and Processing Important Terms and Concepts 504 of Metal Alloys 408 References 505 Questions and Problems 505 Learning Objectives 409 Design Problems 509 11.1 Introduction 409 Fundamentals of Engineering Questions and TYPES OF METAL ALLOYS 410 Problems 509 11.2 Ferrous Alloys 410 11.3 Nonferrous Alloys 422 13. Applications and Processing of Materials of Importance—Metal Alloys Ceramics 510 Used for Euro Coins 433 Learning Objectives 511 FABRICATION OF METALS 434 13.1 Introduction 511 11.4 Forming Operations 434 TYPES AND APPLICATIONS OF CERAMICS 512  Contents xvii 13.2 Glasses 512 15. Characteristics, Applications, and 13.3 Glass–Ceramics 512 Processing of Polymers 580 13.4 Clay Products 514 13.5 Refractories 514 Learning Objectives 581 13.6 Abrasives 516 15.1 Introduction 581 13.7 Cements 517 MECHANICAL BEHAVIOR OF POLYMERS 581 13.8 Carbons 518 15.2 Stress–Strain Behavior 581 13.9 Advanced Ceramics 521 15.3 Macroscopic Deformation 584 FABRICATION AND PROCESSING OF 15.4 Viscoelastic Deformation 584 CERAMICS 525 15.5 Fracture of Polymers 588 13.10 Fabrication and Processing of Glasses and 15.6 Miscellaneous Mechanical Glass–Ceramics 526 Characteristics 590 13.11 Fabrication and Processing of Clay MECHANISMS OF DEFORMATION AND FOR Products 531 STRENGTHENING OF POLYMERS 591 13.12 Powder Pressing 535 15.7 Deformation of Semicrystalline 13.13 Tape Casting 537 Polymers 591 Summary 538 15.8 Factors That Influence the Mechanical Processing/Structure/Properties/Performance Properties of Semicrystalline Summary 540 Polymers 593 Important Terms and Concepts 542 Materials of Importance—Shrink-Wrap References 543 Polymer Films 597 Questions and Problems 543 Design Problem 544 15.9 Deformation of Elastomers 597 Fundamentals of Engineering Questions and CRYSTALLIZATION, MELTING, AND GLASS- Problems 544 TRANSITION PHENOMENA IN POLYMERS 599 15.10 Crystallization 600 14. Polymer Structures 545 15.11 Melting 601 Learning Objectives 546 15.12 The Glass Transition 601 14.1 Introduction 546 15.13 Melting and Glass Transition 14.2 Hydrocarbon Molecules 546 Temperatures 601 14.3 Polymer Molecules 549 15.14 Factors That Influence Melting and Glass 14.4 The Chemistry of Polymer Molecules 549 Transition Temperatures 603 14.5 Molecular Weight 553 POLYMER TYPES 605 14.6 Molecular Shape 556 14.7 Molecular Structure 558 15.15 Plastics 605 14.8 Molecular Configurations 559 Materials of Importance—Phenolic 14.9 Thermoplastic and Thermosetting Billiard Balls 607 Polymers 562 15.16 Elastomers 608 14.10 Copolymers 563 15.17 Fibers 610 14.11 Polymer Crystallinity 564 15.18 Miscellaneous Applications 610 14.12 Polymer Crystals 568 15.19 Advanced Polymeric Materials 612 14.13 Defects in Polymers 570 POLYMER SYNTHESIS AND PROCESSING 616 14.14 Diffusion in Polymeric Materials 571 15.20 Polymerization 616 Summary 573 15.21 Polymer Additives 618 Equation Summary 575 15.22 Forming Techniques for Plastics 620 List of Symbols 575 15.23 Fabrication of Elastomers 622 Processing/Structure/Properties/Performance 15.24 Fabrication of Fibers and Films 622 Summary 575 Summary 624 Important Terms and Concepts 576 Equation Summary 626 References 576 List of Symbols 626 Questions and Problems 577 Processing/Structure/Properties/Performance Fundamentals of Engineering Questions and Summary 626 Problems 579 xviii Contents Important Terms and Concepts 629 17.5 Passivity 698 References 629 17.6 Environmental Effects 699 Questions and Problems 629 17.7 Forms of Corrosion 699 Design Questions 633 17.8 Corrosion Environments 707 Fundamentals of Engineering Question 633 17.9 Corrosion Prevention 707 17.10 Oxidation 709 16. Composites 634 CORROSION OF CERAMIC MATERIALS 712 Learning Objectives 635 DEGRADATION OF POLYMERS 713 16.1 Introduction 635 17.11 Swelling and Dissolution 713 PARTICLE-REINFORCED COMPOSITES 637 17.12 Bond Rupture 715 17.13 Weathering 716 16.2 Large-Particle Composites 637 Summary 717 16.3 Dispersion-Strengthened Composites 641 Equation Summary 719 FIBER-REINFORCED COMPOSITES 642 List of Symbols 719 16.4 Influence of Fiber Length 642 Important Terms and Concepts 720 16.5 Influence of Fiber Orientation and References 720 Concentration 643 Questions and Problems 721 Design Problems 723 16.6 The Fiber Phase 651 Fundamentals of Engineering Questions and 16.7 The Matrix Phase 653 Problems 724 16.8 Polymer-Matrix Composites 653 16.9 Metal-Matrix Composites 659 18. Electrical Properties 725 16.10 Ceramic-Matrix Composites 660 16.11 Carbon–Carbon Composites 662 Learning Objectives 726 16.12 Hybrid Composites 662 18.1 Introduction 726 16.13 Processing of Fiber-Reinforced ELECTRICAL CONDUCTION 726 Composites 663 18.2 Ohm’s Law 726 STRUCTURAL COMPOSITES 665 18.3 Electrical Conductivity 727 16.14 Laminar Composites 665 18.4 Electronic and Ionic Conduction 728 16.15 Sandwich Panels 667 18.5 Energy Band Structures in Case Study—Use of Composites in the Solids 728 Boeing 787 Dreamliner 669 18.6 Conduction in Terms of Band and 16.16 Nanocomposites 670 Atomic Bonding Models 730 Summary 673 18.7 Electron Mobility 732 Equation Summary 675 18.8 Electrical Resistivity of Metals 733 List of Symbols 676 18.9 Electrical Characteristics of Commercial Important Terms and Concepts 676 Alloys 736 References 676 Materials of Importance—Aluminum Questions and Problems 676 Electrical Wires 736 Design Problems 679 Fundamentals of Engineering Questions and SEMICONDUCTIVITY 738 Problems 680 18.10 Intrinsic Semiconduction 738 18.11 Extrinsic Semiconduction 741 17. Corrosion and Degradation 18.12 The Temperature Dependence of Carrier of Materials 681 Concentration 744 18.13 Factors That Affect Carrier Learning Objectives 682 Mobility 745 17.1 Introduction 682 18.14 The Hall Effect 749 CORROSION OF METALS 683 18.15 Semiconductor Devices 751 17.2 Electrochemical Considerations 683 ELECTRICAL CONDUCTION IN IONIC CERAMICS AND IN POLYMERS 757 17.3 Corrosion Rates 689 17.4 Prediction of Corrosion Rates 691 18.16 Conduction in Ionic Materials 758  Contents xix 18.17 Electrical Properties of Polymers 758 20.3 Diamagnetism and Paramagnetism 808 DIELECTRIC BEHAVIOR 759 20.4 Ferromagnetism 810 20.5 Antiferromagnetism 18.18 Capacitance 759 and Ferrimagnetism 811 18.19 Field Vectors and Polarization 761 20.6 The Influence of Temperature on Magnetic 18.20 Types of Polarization 764 Behavior 815 18.21 Frequency Dependence of the Dielectric 20.7 Domains and Hysteresis 816 Constant 766 20.8 Magnetic Anisotropy 819 18.22 Dielectric Strength 767 20.9 Soft Magnetic Materials 820 18.23 Dielectric Materials 767 Materials of Importance—An OTHER ELECTRICAL CHARACTERISTICS OF Iron–Silicon Alloy Used in MATERIALS 767 Transformer Cores 821 18.24 Ferroelectricity 767 20.10 Hard Magnetic Materials 822 18.25 Piezoelectricity 768 20.11 Magnetic Storage 825 Materials of Importance—Piezoelectric 20.12 Superconductivity 828 Ceramic Ink-Jet Printer Heads 769 Summary 831 Summary 770 Equation Summary 833 Equation Summary 773 List of Symbols 833 List of Symbols 774 Important Terms and Concepts 834 Processing/Structure/Properties/Performance References 834 Summary 774 Questions and Problems 834 Important Terms and Concepts 778 Design Problems 837 References 778 Fundamentals of Engineering Questions and Questions and Problems 778 Problems 837 Design Problems 782 Fundamentals of Engineering Questions and Problems 783 21. Optical Properties 838 Learning Objectives 839 19. Thermal Properties 785 21.1 Introduction 839 Learning Objectives 786 BASIC CONCEPTS 839 19.1 Introduction 786 21.2 Electromagnetic Radiation 839 19.2 Heat Capacity 786 21.3 Light Interactions with Solids 841 19.3 Thermal Expansion 790 21.4 Atomic and Electronic Materials of Importance—Invar Interactions 842 and Other Low-Expansion OPTICAL PROPERTIES OF METALS 843 Alloys 792 19.4 Thermal Conductivity 793 OPTICAL PROPERTIES OF NONMETALS 844 19.5 Thermal Stresses 796 21.5 Refraction 844 Summary 798 21.6 Reflection 846 Equation Summary 799 21.7 Absorption 846 List of Symbols 799 21.8 Transmission 850 Important Terms and Concepts 800 21.9 Color 850 References 800 21.10 Opacity and Translucency in Questions and Problems 800 Insulators 852 Design Problems 802 Fundamentals of Engineering Questions and APPLICATIONS OF OPTICAL Problems 802 PHENOMENA 853 21.11 Luminescence 853 21.12 Photoconductivity 853 20. Magnetic Properties 803 Materials of Importance—Light-Emitting Learning Objectives 804 Diodes 854 20.1 Introduction 804 21.13 Lasers 856 20.2 Basic Concepts 804 21.14 Optical Fibers in Communications 860 xx Contents Summary 862 Appendix A The International System of Equation Summary 864 Units (SI) 880 List of Symbols 865 Important Terms and Concepts 865 Appendix B Properties of Selected References 865 Engineering Materials 882 Questions and Problems 866 B.1 Density 882 Design Problem 867 Fundamentals of Engineering Questions and B.2 Modulus of Elasticity 885 Problems 867 B.3 Poisson’s Ratio 889 B.4 Strength and Ductility 890 B.5 Plane Strain Fracture Toughness 895 22. Economic, Environmental, and B.6 Linear Coefficient of Thermal Societal Issues in Materials Expansion 897 Science and Engineering 868 B.7 Thermal Conductivity 900 B.8 Specific Heat 903 Learning Objectives 869 B.9 Electrical Resistivity 906 22.1 Introduction 869 B.10 Metal Alloy Compositions 909 ECONOMIC CONSIDERATIONS 869 Appendix C Costs and Relative Costs for 22.2 Component Design 870 Selected Engineering Materials 911 22.3 Materials 870 22.4 Manufacturing Techniques 870 Appendix D Repeat Unit Structures for ENVIRONMENTAL AND SOCIETAL Common Polymers 916 CONSIDERATIONS 871 Appendix E Glass Transition and Melting 22.5 Recycling Issues in Materials Science Temperatures for Common Polymeric and Engineering 873 Materials 920 Materials of Importance—Biodegradable Glossary 921 and Biorenewable Polymers/ Plastics 876 Answers to Selected Problems 934 Summary 878 Index 939 References 879 Design Questions 879  List of Symbols T he number of the section in which a symbol is introduced or explained is given in parentheses. A = area dhkl = interplanar spacing for planes Å = angstrom unit of Miller indices h, k, and l Ai = atomic weight of (3.16) element i (2.2) E = energy (2.5) APF = atomic packing factor (3.4) E = modulus of elasticity or a = lattice parameter: unit cell Young’s modulus (6.3) x-axial length (3.4) e = electric field intensity (18.3) a = crack length of a surface crack Ef = Fermi energy (18.5) (8.5) Eg = band gap energy (18.6) at% = atom percent (4.4) Er(t) = relaxation modulus (15.4) B = magnetic flux density %EL = ductility, in percent elongation (induction) (20.2) (6.6) Br = magnetic remanence (20.7) e = electric charge per electron BCC = body-centered cubic crystal (18.7) structure (3.4) e- = electron (17.2) b = lattice parameter: unit cell erf = Gaussian error function (5.4) y-axial length (3.7) exp = e, the base for natural b = Burgers vector (4.5) logarithms C = capacitance (18.18) F = force, interatomic or Ci = concentration (composition) of mechanical (2.5, 6.2) component i in wt% (4.4) f = Faraday constant (17.2) C¿i = concentration (composition) of FCC = face-centered cubic crystal component i in at% (4.4) structure (3.4) Cy, Cp = heat capacity at constant G = shear modulus (6.3) volume, pressure (19.2) H = magnetic field strength (20.2) CPR = corrosion penetration rate Hc = magnetic coercivity (20.7) (17.3) HB = Brinell hardness (6.10) CVN = Charpy V-notch (8.6) HCP = hexagonal close-packed crystal %CW = percent cold work (7.10) structure (3.4) c = lattice parameter: unit cell HK = Knoop hardness (6.10) z-axial length (3.7) HRB, HRF = Rockwell hardness: B and F c = velocity of electromagnetic scales (6.10) radiation in a vacuum (21.2) HR15N, HR45W = superficial Rockwell hardness: D = diffusion coefficient (5.3) 15N and 45W scales (6.10) D = dielectric displacement (18.19) HV = Vickers hardness (6.10) DP = degree of polymerization (14.5) h = Planck’s constant (21.2) d = diameter (hkl) = Miller indices for a crystallo- d = average grain diameter (7.8) graphic plane (3.10) xxi xxii List of Symbols (hkil) = Miller indices for a crystal- r = reaction rate (17.3) lographic plane, hexagonal rA, rC = anion and cation ionic radii crystals (3.10) (12.2) I = electric current (18.2) S = fatigue stress amplitude (8.8) I = intensity of electromagnetic SEM = scanning electron microscopy radiation (21.3) or microscope i = current density (17.3) T = temperature iC = corrosion current density (17.4) Tc = Curie temperature (20.6) J = diffusion flux (5.3) TC = superconducting critical J = electric current density (18.3) temperature (20.12) Kc = fracture toughness (8.5) Tg = glass transition temperature KIc = plane strain fracture tough- (13.10, 15.12) ness for mode I crack surface Tm = melting temperature displacement (8.5) TEM = transmission electron k = Boltzmann’s constant (4.2) microscopy or microscope k = thermal conductivity (19.4) TS = tensile strength (6.6) l = length t = time lc = critical fiber length (16.4) tr = rupture lifetime (8.12) ln = natural logarithm Ur = modulus of resilience (6.6) log = logarithm taken to base 10 [uyw] = indices for a crystallographic M = magnetization (20.2) direction (3.9) Mn = polymer number-average [uvtw], [UVW] = indices for a crystallographic molecular weight (14.5) direction, hexagonal crystals Mw = polymer weight-average (3.9) molecular weight (14.5) V = electrical potential difference mol% = mole percent (voltage) (17.2, 18.2) N = number of fatigue cycles (8.8) VC = unit cell volume (3.4) NA = Avogadro’s number (3.5) VC = corrosion potential (17.4) Nf = fatigue life (8.8) VH = Hall voltage (18.14) n = principal quantum number (2.3) Vi = volume fraction of phase i (9.8) n = number of atoms per unit cell y = velocity (3.5) vol% = volume percent n = strain-hardening exponent (6.7) Wi = mass fraction of phase i (9.8) n = number of electrons in an wt% = weight percent (4.4) electrochemical reaction (17.2) x = length n = number of conducting elec- x = space coordinate trons per cubic meter (18.7) Y = dimensionless parameter or n = index of refraction (21.5) function in fracture toughness n¿ = for ceramics, the number of expression (8.5) formula units per unit cell y = space coordinate (12.2) z = space coordinate ni = intrinsic carrier (electron and a = lattice parameter: unit cell y–z hole) concentration (18.10) interaxial angle (3.7) P = dielectric polarization (18.19) a, b, g = phase designations P–B ratio = Pilling–Bedworth ratio (17.10) al = linear coefficient of thermal p = number of holes per cubic expansion (19.3) meter (18.10) b = lattice parameter: unit cell x–z Q = activation energy interaxial angle (3.7) Q = magnitude of charge stored g = lattice parameter: unit cell x–y (18.18) interaxial angle (3.7) R = atomic radius (3.4) g = shear strain (6.2) R = gas constant ¢ = precedes the symbol of a pa- %RA = ductility, in percent reduction rameter to denote finite change in area (6.6) P = engineering strain (6.2) r = interatomic distance (2.5) P = dielectric permittivity (18.18)  List of Symbols xxiii Pr = dielectric constant or relative s¿m = stress in matrix at composite permittivity (18.18) failure (16.5). Ps = steady-state creep rate (8.12) sT = true stress (6.7) PT = true strain (6.7) sw = safe or working stress (6.12) h = viscosity (12.10) sy = yield strength (6.6) h = overvoltage (17.4) t = shear stress (6.2) 2u = Bragg diffraction angle (3.16) tc = fiber–matrix bond strength/ uD = Debye temperature (19.2) matrix shear yield strength l = wavelength of electromagnetic (16.4) radiation (3.16) tcrss = critical resolved shear stress m = magnetic permeability (20.2) (7.5) mB = Bohr magneton (20.2) xm = magnetic susceptibility mr = relative magnetic permeability (20.2) (20.2) me = electron mobility (18.7) mh = hole mobility (18.10) Subscripts n = Poisson’s ratio (6.5) c = composite n = frequency of electromagnetic cd = discontinuous fibrous radiation (21.2) composite r = density (3.5) cl = longitudinal direction (aligned r = electrical resistivity (18.2) fibrous composite) rt = radius of curvature at the tip of ct = transverse direction (aligned a crack (8.5) fibrous composite) s = engineering stress, tensile or f = final compressive (6.2) f = at fracture s = electrical conductivity (18.3) f = fiber s* = longitudinal strength (compos- i = instantaneous ite) (16.5) m = matrix sc = critical stress for crack propa- m, max = maximum gation (8.5) min = minimum sfs = flexural strength (12.9) 0 = original sm = maximum stress (8.5) 0 = at equilibrium sm = mean stress (8.7) 0 = in a vacuum  Chapter 1 Introduction © iStockphoto/Mark Oleksiy © blickwinkel/Alamy A familiar item fabricated from three different material types is the © iStockphoto/Jill Chen beverage container. Beverages are marketed in aluminum (metal) cans (top), glass (ceramic) bottles (center), and plastic (polymer) bottles (bottom). © iStockphoto/Mark Oleksiy © blickwinkel/Alamy 1 Learning Objectives After studying this chapter, you should be able to do the following: 1. List six different property classifications of mate- 4. (a) List the three primary classifications rials that determine their applicability. of solid materials, and then cite the 2. Cite the four components that are involved in distinctive chemical feature of each. the design, production, and utilization of materi- (b) Note the four types of advanced materials als, and briefly describe the interrelationships and, for each, its distinctive feature(s). between these components. 5. (a) Briefly define smart material/system. 3. Cite three criteria that are important in the ma- (b) Briefly explain the concept of nanotechnol- terials selection process. ogy as it applies to materials. 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 discovered techniques for producing materials that had properties superior to those of the natural ones; these new materials included pottery and various metals. Furthermore, 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 utilization 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 characteristics. It was not until relatively recent times that scientists came to understand the relationships between the structural elements of materials and their proper- ties. 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 thousands of dif- ferent materials have evolved with rather specialized characteristics that meet the needs of our modern and complex society, including metals, plastics, glasses, and fibers. The development of many technologies that make our existence so comfortable has been intimately associated with the accessibility of suitable materials. An advance- ment in the understanding of a material type is often the forerunner 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 the contemporary era, sophisticated electronic devices rely on components that are made from what are called semiconducting materials. 1.2 MATERIALS SCIENCE AND ENGINEERING Sometimes it is useful to subdivide the discipline of materials science and engineering into materials science and materials engineering subdisciplines. Strictly speaking, materi- als science involves investigating the relationships that exist between the structures and 1 The approximate dates for the beginnings of the Stone, Bronze, and Iron ages are 2.5 million bc, 3500 bc, and 1000 bc, respectively. 2  1.2 Materials Science and Engineering 3 properties of materials. In contrast, materials engineering involves, on the basis of these structure–property correlations, designing or engineering the structure of a material to produce a predetermined set of properties.2 From a functional perspective, the role of a materials scientist is to develop or synthesize new materials, whereas a materials engi- neer 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 organization of atoms or molecules relative to one another. The next larger structural realm, which contains large groups of atoms that are normally agglomerated together, is termed microscopic, mean- ing that which is subject to direct observation using some type of microscope. Finally, structural elements that can 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 experiences deformation, or a polished metal surface reflects 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 mate- rial shape and size. Virtually all important properties of solid materials may be grouped into six differ- ent categories: mechanical, electrical, thermal, magnetic, optical, and deteriorative. For each, there is a characteristic type of stimulus capable of provoking different responses. Mechanical properties relate deformation to an applied load or force; examples include elastic modulus (stiffness), strength, and toughness. For electrical properties, such as electrical conductivity and dielectric constant, the stimulus is an electric field. The thermal behavior of solids can be represented in terms of heat capacity and thermal conductivity. Magnetic properties demonstrate the response of a material to the ap- plication of a magnetic field. For optical properties, the stimulus is electromagnetic or light radiation; index of refraction and reflectivity 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 in- volved in the science and engineering of materials—namely, processing and perform- ance. With regard to the relationships of these four components, the structure of a material depends on how it is processed. Furthermore, a material’s performance is a function of its properties. Thus, the interrelationship among processing, structure, prop- erties, and performance is as depicted in the schematic illustration shown in Figure 1.1. Throughout this text, we draw attention to the relationships among these four compo- nents in terms of the design, production, and utilization of materials. We present an example of these processing-structure-properties-performance prin- ciples in 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 transmittance) of each of the three materials are different; the one on the left is transparent (i.e., virtually all of the Processing Structure Properties Performance Figure 1.1 The four components of the discipline of materials science and engineering and their interrelationship. 2 Throughout this text, we draw attention to the relationships between material properties and structural elements. 4 Chapter 1 / Introduction 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 Specimen preparation, P. A. Lessing 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. reflected light passes through it), whereas the disks in the center and on the right are, respec- tively, translucent and opaque. All of these specimens 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 transparency. 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 ma- terial 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. Furthermore, each material was produced using a different processing technique. If optical transmit- tance is an important parameter relative to the ultimate in-service application, the per- formance of each material will be different. 1.3 WHY STUDY MATERIALS SCIENCE AND ENGINEERING? Why do we study materials? Many an applied scientist or engineer, whether mechani- cal, civil, chemical, or electrical, is at one time or another exposed to a design problem involving materials, such as a transmission gear, the superstructure for a building, an oil refinery component, or an integrated circuit chip. Of course, materials scientists and engineers are specialists who are totally involved in the investigation and design of materials. Many times, a materials problem is one of selecting the right material from the thousands available. The final decision is normally based on several criteria. First, the in-service conditions must be characterized, for these dictate the properties required of the material. On only rare occasions does a material possess the maximum or ideal com- bination of properties. Thus, it may be necessary to trade one characteristic for another. The classic example involves strength and ductility; normally, a material having a high strength has only a limited ductility. In such cases, a reasonable compromise between two or more properties may be necessary. A second selection consideration is any deterioration of material properties that may occur during service operation. For example, significant reductions in mechanical strength may result from exposure to elevated temperatures or corrosive environments.  1.3 Why Study Materials Science and Engineering? 5 Finally, probably the overriding consideration is that of economics: What will the finished product cost? A material may be found that has the ideal set of properties but is prohibitively expensive. Here again, some compromise is inevitable. The cost of a finished piece also includes any expense incurred during fabrication to produce the desired shape. The more familiar an engineer or scientist is with the various characteristics and structure–property relationships, as well as the processing techniques of materials, the more proficient and confident he or she will be in making judicious materials choices based on these criteria. C A S E S T U D Y Liberty Ship Failures T he following case study illustrates one role that materials scientists and engineers are called upon to assume in the area of materials performance: experienced a ductile-to-brittle transition. Some of them were deployed to the frigid North Atlan- tic, where the once ductile metal experienced brit- analyze mechanical failures, determine their causes, tle fracture when temperatures dropped to below and then propose appropriate measures to guard the transition temperature.6 against future incidents. The corner of each hatch (i.e., door) was square; The failure of many of the World War II Liberty these corners acted as points of stress concentra- ships3 is a well-known and dramatic example of the tion where cracks can form. brittle fracture of steel that was thought to be duc- German U-boats were sinking cargo ships faster tile.4 Some of the early ships experienced structural than they could be replaced using existing con- damage when cracks developed in their decks and struction techniques. Consequently, it became hulls. Three of them catastrophically split in half when necessary to revolutionize construction methods cracks formed, grew to critical lengths, and then rap- to build cargo ships faster and in greater numbers. idly propagated completely around the ships’ girths. This was accomplished using prefabricated steel Figure 1.3 shows one of the ships that fractured the sheets that were assembled by welding rather day after it was launched. than by the traditional time-consuming riveting. Subsequent investigations concluded one or more Unfortunately, cracks in welded structures may of the following factors contributed to each failure5: propagate unimpeded for large distances, which When some normally ductile metal alloys are can lead to catastrophic failure. However, when cooled to relatively low temperatures, they be- structures are riveted, a crack ceases to propagate come susceptible to brittle fracture—that is, they once it reaches the edge of a steel sheet. experience a ductile-to-brittle transition upon Weld defects and discontinuities (i.e., sites where cooling through a critical range of temperatures. cracks can form) were introduced by inexperi- These Liberty ships were constructed of steel that enced operators. 3 During World War II, 2,710 Liberty cargo ships were mass-produced by the United States to supply food and materials to the combatants in Europe. 4 Ductile metals fail after relatively large degrees of permanent deformation; however, very little if any permanent deformation accompanies the fracture of brittle materials. Brittle fractures can occur very suddenly as cracks spread rapidly; crack propagation is normally much slower in ductile materials, and the eventual fracture takes longer. For these reasons, the ductile mode of fracture is usually preferred. Ductile and brittle fractures are discussed in Sections 8.3 and 8.4. 5 Sections 8.2 through 8.6 discuss various aspects of failure. 6 This ductile-to-brittle transition phenomenon, as well as techniques that are used to measure and raise the critical temperature range, are discussed in Section 8.6. (continued) 6 Chapter 1 / Introduction Figure 1.3 The Liberty ship S.S. Schenectady, which, in 1943, failed before leaving the shipyard. (Reprinted with permission of Earl R. Parker, Brittle Behavior of Engineering Structures, National Academy of Sciences, National Research Council, John Wiley & Sons, New York, 1957.) Remedial measures taken to correct these prob- Improving welding practices and establishing weld- lems included the following: ing codes. Lowering the ductile-to-brittle temperature of In spite of these failures, the Liberty ship program the steel to an acceptable level by improving steel was considered a success for several reasons, the pri- quality (e.g., reducing sulfur and phosphorus im- mary reason being that ships that survived failure were purity contents). able to supply Allied Forces in the theater of operations Rounding off hatch corners by welding a curved and in all likelihood shortened the war. In addition, reinforcement strip on each corner.7 structural steels were developed with vastly improved resistances to catastrophic brittle fractures. Detailed Installing crack-arresting devices such as riveted analyses of these failures advanced the understand- straps and strong weld seams to stop propagating ing of crack formation and growth, which ultimately cracks. evolved into the discipline of fracture mechanics. 7 The reader may note that corners of windows and doors for all of today’s marine and aircraft structures are rounded. 1.4 CLASSIFICATION OF MATERIALS Solid materials have been conveniently grouped into three basic categories: metals, ce- ramics, and polymers, a scheme based primarily on chemical makeup and atomic struc- ture. Most materials fall into one distinct grouping or another. In addition, there are the Tutorial Video: What are the composites that are engineered combinations of two or more different materials. A brief Different Classes explanation of these material classifications and representative characteristics is offered of Materials? next. Another category is advanced materials—those used in high-technology applica- tions, such as semiconductors, biomaterials, smart materials, and nanoengineered mate- rials; these are discussed in Section 1.5.  1.4 Classification of Materials 7 Figure 1.4 40 Metals Bar chart of room- temperature density 20 Platinum values for various Silver Density (g/cm3) (logarithmic scale) metals, ceramics, Ceramics