Table Of Content

GUMPR 11/15/02 8:44 PM Page iii Navigating the Materials World A Guide to Understanding Materials Behavior Edited by Caroline Baillie Imperial College of Science Linda Vanasupa California Polytechnic State University Amsterdam Boston London New York Oxford Paris San Diego San Francisco Singapore Sydney Tokyo GUMPR 12/7/02 3:50 PM Page iv This book is printed on acid-free paper. Copyright 2003,Elsevier Science (USA). All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means,electronic or mechanical,including photocopy,recording,or any information storage and retrieval system,without permission in writing from the publisher.Requests for permission to make copies of any part of the work should be mailed to the following address:Permissions Department,Harcourt,Inc.,6277 Sea Harbor Drive, Orlando,Florida,32887-6777. Illustrations by Z*ghygoem [email protected] ACADEMIC PRESS An imprint of Elsevier Science 525 B Street,Suite 1900,San Diego,CA 92101-4495,USA http://www.academicpress.com Academic Press 84 Theobald’s Road,London WC1X 8RR,UK http://www.academicpress.com Library of Congress Control Number:2002108381 International Standard Book Number:0-12-073551-2 PRINTED IN CHINA 03 04 05 06 07 08 9 8 7 6 5 4 3 2 1 GUMPR 11/15/02 8:44 PM Page v CONTENTS Acknowledgments xi Contributors xiii 1 Welcome to the Materials World 1 The Clues: How to Discover the Facts 2 Effects 3 Concepts 3 Constructs 4 Your Mission 5 Clues About the Culture 7 Capabilities: Developing Your Potential for the Mission 9 Tools for the Mission 9 Planning Your Mission 10 2 Visiting the Travel Agency (or Selecting Your Material) 13 Design 14 Materials 17 Relationships 18 Translations 19 Selection Criteria 20 Values and Experience 20 Engineering Properties 22 Natural Materials 23 Engineering Constructs in Use 24 v GUMPR 11/15/02 8:44 PM Page vi vi Contents Life Cycle Assessment 24 Processing 26 Finishing 28 Summing Up 29 3 The Tool Shop (or Characterizing Your Material) 31 Overview 32 An Approach to Characterization 32 Step 1:The Question 32 Step 2:Techniques 34 Step 3:The Observations 38 Step 4: Interpretation 39 Step 5: Refine the Question 41 Some Important Concepts Associated with Characterizations 42 Phase 42 Crystal Structure 43 Scale and Magnification 44 Resolution 45 Pixels 47 Channels 48 Interaction Volume 48 Sensitivity 49 Accuracy 49 Your Mission 50 Acronyms Used in this Chapter 50 4 Entering the Metals Zone 53 Introduction 54 Metals, Metals, Everywhere 54 Communication Is Needed for Any Relationship (Misconceptions) 55 Free Electrons (the Basic Chemistry of Metals) 58 In the Beginning There Was Adam...Well,Actually the Atom 58 Chemical Attraction 59 Electron Speed Limit: None? 59 Ticket to Anywhere 60 Bonding 63 Personality Traits of Metals 63 Help Me, I’m Melting... 63 Stretchy and Springy 64 Atomic Arrangements (Crystal Structures) 64 Strong,Yet Gentle 64 Travel Smartly and Pack Efficiently 65 Crystal Clear 67 And Now for Something Different 68 GUMPR 11/15/02 8:44 PM Page vii Contents vii Defects (Imperfections in Crystals) 70 A Nonperfect,Yet Interesting,World 70 Small Things with Large Consequences 71 This One Is Too Small,This One Is Too Big, But This One Is Just Right (Microstructures) 72 Defect Interactions 73 Building Muscle (Strengthening Mechanisms) 73 Phase Stability and Transformations? 75 How Do We Get There From Here? (Processing) 75 It’s Just a Phase 76 Joy of Processing (Fabrication and Annealing) 78 Pygmalion...Microstructural Evolution 79 Conclusion 82 Putting It All Together 82 5 A Tour of Ceramic Land 85 Common Misconceptions 86 Ceramics:What Are They? 87 Ceramics: How Are They Used? 88 Source of Ceramic Properties 91 Examples of Links Between Structure and Properties 92 Ceramics Melt at High Temperatures 92 Some Ceramics Can Emit Light 92 More on Crystal Structures 94 The Structure of Glass 95 Crystal Structures of Traditional Ceramics 95 Advanced Ceramics 98 How Do You Make a Ceramic Product? 99 Process Flow Diagram for a Traditional Ceramic 101 Ceramic Processes 103 Advanced Ceramic Processing 104 Ceramic Processes: Unifying Concepts 104 Performance 106 Parting Thoughts 108 6 Interfacing with Composites 111 Structure 112 Interface 112 Bonds (Different Types of Relationships) 113 Pull-Out 115 Debonding (Breaking Up) 116 Measuring the Bond 116 Laminate Design and Properties 119 Structure Property Relationships 120 GUMPR 11/15/02 8:44 PM Page viii viii Contents Mechanics of Short Fiber: Shear Lag 123 External Environment 124 Design Tools 124 Failure Analysis 126 Failure Mechanisms 127 Processing 128 Open Mold Processing 129 Autoclave Molding 130 Compression Molding 130 Filament Winding 130 Pultrusion 130 Liquid Molding 130 Processing Methods for Thermoplastics 131 7 The Land of Polymers 135 How Are Polymers Made? (How Do We Form the Team?) 137 What Stops the Team from Growing Too Big? 137 Termination 138 Inhibition 139 Autoacceleration 140 Chain Transfer 140 Nonlinear Step Polymerization 141 Copolymerization 141 Structure 142 Categorization 143 Crystallization 144 Crystal Defects 147 Processing Route 148 Making Things with Thermoplastics 148 Compression and Transfer Molding 148 Injection Molding 148 Extrusion 149 Blow Molding 149 Rotational Molding 149 Calendaring 149 Foaming 150 Vacuum Forming 150 Making Things with Thermosets 150 Interaction of Structure and Processing 150 Polymer Behavior 152 How Easily Will the Team Break Up and How Does It Behave? 152 Static Behavior at Room Temperature 153 Five Regions of Deformation 154 Stress Relaxation 156 GUMPR 11/15/02 8:44 PM Page ix Contents ix Recovery 156 Time Temperature Correspondence 156 Models 157 Polymer Degradation 158 8 Back to Nature 161 You’ve Earned a Holiday! 162 Biological Natural Materials 163 Geological Natural Materials 163 Traditional Natural Materials 164 Protein-Based Traditional Natural Materials 164 Wool 164 Silk 165 Plant-Based Traditional Natural Materials 167 Natural Polymers 167 Natural Rubber 167 Starch 168 Lignin 169 Pectin 169 Cellulose 170 Hemicellulose 172 Cellulose Fibers 173 Wood 174 Leaf Fibers: Sisal 183 Bast Fibers: Jute, Hemp, and Flax 187 9 An Electronic Trip Through Semiconductors 195 Welcome 196 The Concept Map 197 What Is a Semiconductor? 199 Electrons in Energy Space: Energy Bands 200 Generation of Charge Carriers 204 Thermal Generation of Charge Carriers 204 Photogeneration of Charge Carriers 207 Impurity Doping 208 Thermal Equilibrium in Semiconductors 211 Conductivity and Mobility 211 Carrier Mobility 212 Conductivity Dependence on Temperature 214 Optical Properties of Semiconductors 214 Light-Absorbing Semiconductors 214 Light-Emitting Semiconductors 215 Summing Up 216 GUMPR 11/15/02 8:44 PM Page x x Contents 10 Accident and Emergency 219 Introduction 220 Ductile or Brittle:A Competition 222 Ductile Failure: Fast Fracture 222 Ductile Failure: Creep 225 Brittle Failure: Fast Fracture 227 Brittle Failure: Fatigue 230 Index 237 GUMPR 11/15/02 8:44 PM Page xi ACKNOWLEDGMENTS The first thanks must go to Cordelia Sealy who enabled the whole thing and supported what seemed at times like a crazy plan—to bring together pairs of authors—Materials Scientists with Educational Specialists,to help students learn how to learn materials concepts.Caroline and Linda would like to thank all of the authors for involving themselves in what has become a hugely exciting project.We needed to meet from time to time, so thanks must go to the UK Centre for Materials Education for their support throughout and for enabling Caroline to meet with Linda and Emily at various times in the US, also to John for finding a reason to meet in Sweden.And finally, thanks to Caroline’s mum for believing. xi