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Materials Engineering, Science, Processing and Design Michael Ashby, Hugh Shercliff and David Cebon University of Cambridge, UK AMSTERDAM • BOSTON • HEIDELBERG • LONDON • NEW YORK • OXFORD PARIS • SAN DIEGO • SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Butterworth-Heinemann is an imprint of Elsevier...

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Materials Engineering, Science, Processing and Design

Michael Ashby, Hugh Shercliff and David Cebon University of Cambridge, UK

AMSTERDAM • BOSTON • HEIDELBERG • LONDON • NEW YORK • OXFORD PARIS • SAN DIEGO • SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Butterworth-Heinemann is an imprint of Elsevier

Butterworth-Heinemann is an imprint of Elsevier Linacre House, Jordan Hill, Oxford OX2 8DP 30 Corporate Drive, Suite 400, Burlington, MA 01803 First edition 2007 Copyright © 2007, Michael Ashby, Hugh Shercliff and David Cebon. Published by Elsevier Ltd. All rights reserved. The right of Michael Ashby, Hugh Shercliff and David Cebon to be identified as the authors of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988 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 or otherwise without the prior written permission of the publisher Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone (⫹44) (0) 1865 843830; fax: (⫹44) (0) 1865 853333; email: [email protected]. Alternatively you can submit your request online by visiting the Elsevier web site at http://elsevier.com/locate/ permissions, and selecting Obtaining permission to use Elsevier material Notice No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein. Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress ISBN-13: 978-0-7506-8391-3 ISBN-10: 0-7506-8391-0 For information on all Butterworth-Heinemann publications visit our web site at http://books.elsevier.com

Typeset by Charon Tec Ltd (A Macmillan Company), Chennai, India. www.charontec.com Printed and bound in the UK 07 08 09 10

10 9 8 7 6 5 4 3 2 1

Contents Preface Acknowledgements Resources that accompany this book

ix xi xii

Chapter 1 Introduction: materials—history and character 1.1 Materials, processes and choice 1.2 Material properties 1.3 Design-limiting properties 1.4 Summary and conclusions 1.5 Further reading 1.6 Exercises

1 2 4 9 10 10 10

Chapter 2 Family trees: organizing materials and processes 2.1 Introduction and synopsis 2.2 Getting materials organized: the materials tree 2.3 Organizing processes: the process tree 2.4 Process–property interaction 2.5 Material property charts 2.6 Computer-aided information management for materials and processes 2.7 Summary and conclusions 2.8 Further reading 2.9 Exercises 2.10 Exploring design using CES 2.11 Exploring the science with CES Elements

13 14 14 18 21 22 24 25 26 26 28 28

Chapter 3 Strategic thinking: matching material to design 3.1 Introduction and synopsis 3.2 The design process 3.3 Material and process information for design 3.4 The strategy: translation, screening, ranking and documentation 3.5 Examples of translation 3.6 Summary and conclusions 3.7 Further reading 3.8 Exercises 3.9 Exploring design using CES

29 30 30 34 36 39 43 43 44 46

iv Contents Chapter 4 Stiffness and weight: density and elastic moduli 4.1 Introduction and synopsis 4.2 Density, stress, strain and moduli 4.3 The big picture: material property charts 4.4 The science: what determines density and stiffness? 4.5 Manipulating the modulus and density 4.6 Summary and conclusions 4.7 Further reading 4.8 Exercises 4.9 Exploring design with CES 4.10 Exploring the science with CES Elements

47 48 48 56 58 69 73 74 74 77 78

Chapter 5 Flex, sag and wobble: stiffness-limited design 5.1 Introduction and synopsis 5.2 Standard solutions to elastic problems 5.3 Material indices for elastic design 5.4 Plotting limits and indices on charts 5.5 Case studies 5.6 Summary and conclusions 5.7 Further reading 5.8 Exercises 5.9 Exploring design with CES 5.10 Exploring the science with CES Elements

81 82 82 89 95 99 106 107 107 109 109

Chapter 6 Beyond elasticity: plasticity, yielding and ductility 6.1 Introduction and synopsis 6.2 Strength, plastic work and ductility: definition and measurement 6.3 The big picture: charts for yield strength 6.4 Drilling down: the origins of strength and ductility 6.5 Manipulating strength 6.6 Summary and conclusions 6.7 Further reading 6.8 Exercises 6.9 Exploring design with CES 6.10 Exploring the science with CES Elements

111 112 112 116 118 127 135 136 137 138 138

Chapter 7 Bend and crush: strength-limited design 7.1 Introduction and synopsis 7.2 Standard solutions to plastic problems 7.3 Material indices for yield-limited design 7.4 Case studies 7.5 Summary and conclusions 7.6 Further reading

141 142 142 149 154 158 159

Contents 7.7 7.8

Exercises Exploring design with CES

v

159 161

Chapter 8 Fracture and fracture toughness 8.1 Introduction and synopsis 8.2 Strength and toughness 8.3 The mechanics of fracture 8.4 Material property charts for toughness 8.5 Drilling down: the origins of toughness 8.6 Manipulating properties: the strength–toughness trade-off 8.7 Summary and conclusions 8.8 Further reading 8.9 Exercises 8.10 Exploring design with CES 8.11 Exploring the science with CES Elements

163 164 164 166 172 174 178 181 181 182 183 183

Chapter 9 Shake, rattle and roll: cyclic loading, damage and failure 9.1 Introduction and synopsis 9.2 Vibration and resonance: the damping coefficient 9.3 Fatigue 9.4 Charts for endurance limit 9.5 Drilling down: the origins of damping and fatigue 9.6 Manipulating resistance to fatigue 9.7 Summary and conclusions 9.8 Further reading 9.9 Exercises 9.10 Exploring design with CES

185 186 186 187 194 195 196 198 199 199 202

Chapter 10 Keeping it all together: fracture-limited design 10.1 Introduction and synopsis 10.2 Standard solutions to fracture problems 10.3 Material indices for fracture-safe design 10.4 Case studies 10.5 Summary and conclusions 10.6 Further reading 10.7 Exercises 10.8 Exploring design with CES

203 204 204 205 209 220 221 221 224

Chapter 11 Rub, slither and seize: friction and wear 11.1 Introduction and synopsis 11.2 Tribological properties 11.3 Charting friction and wear 11.4 The physics of friction and wear3

227 228 228 229 231

vi Contents 11.5 11.6 11.7 11.8 11.9

Design and selection: materials to manage friction and wear Summary and conclusions Further reading Exercises Exploring design with CES

235 240 241 241 243

Chapter 12 Agitated atoms: materials and heat 12.1 Introduction and synopsis 12.2 Thermal properties: definition and measurement 12.3 The big picture: thermal property charts 12.4 Drilling down: the physics of thermal properties 12.5 Manipulating thermal properties 12.6 Design to exploit thermal properties 12.7 Summary and conclusions 12.8 Further reading 12.9 Exercises 12.10 Exploring design with CES 12.11 Exploring the science with CES Elements

245 246 246 249 251 257 258 268 269 270 271 272

Chapter 13 Running hot: using materials at high temperatures 13.1 Introduction and synopsis 13.2 The temperature dependence of material properties 13.3 Charts for creep behavior 13.4 The science: diffusion and creep 13.5 Materials to resist creep 13.6 Design to cope with creep 13.7 Summary and conclusions 13.8 Further reading 13.9 Exercises 13.10 Exploring design with CES 13.11 Exploring the science with CES Elements

275 276 276 281 284 293 296 304 305 305 308 308

Chapter 14 Conductors, insulators and dielectrics 14.1 Introduction and synopsis 14.2 Conductors, insulators and dielectrics 14.3 Charts for electrical properties 14.4 Drilling down: the origins and manipulation of electrical properties 14.5 Design: using the electrical properties of materials 14.6 Summary and conclusions 14.7 Further reading 14.8 Exercises 14.9 Exploring design with CES 14.10 Exploring the science with CES Elements

311 312 313 317 320 331 338 338 339 341 343

Contents

vii

Chapter 15 Magnetic materials 15.1 Introduction and synopsis 15.2 Magnetic properties: definition and measurement 15.3 Charts for magnetic properties 15.4 Drilling down: the physics and manipulation of magnetic properties 15.5 Materials selection for magnetic design 15.6 Summary and conclusions 15.7 Further reading 15.8 Exercises 15.9 Exploring design with CES 15.10 Exploring the science with CES Elements

345 346 346 351 353 358 363 363 364 365 366

Chapter 16 Materials for optical devices 16.1 Introduction and synopsis 16.2 The interaction of materials and radiation 16.3 Charts for optical properties 16.4 Drilling down: the physics and manipulation of optical properties 16.5 Optical design 16.6 Summary and conclusions 16.7 Further reading 16.8 Exercises 16.9 Exploring design with CES 16.10 Exploring the science with CES Elements

367 368 368 373 375 381 382 383 383 384 385

Chapter 17 Durability: oxidation, corrosion and degradation 17.1 Introduction and synopsis 17.2 Oxidation, flammability and photo-degradation 17.3 Oxidation mechanisms 17.4 Making materials that resist oxidation 17.5 Corrosion: acids, alkalis, water and organic solvents 17.6 Drilling down: mechanisms of corrosion 17.7 Fighting corrosion 17.8 Summary and conclusions 17.9 Further reading 17.10 Exercises 17.11 Exploring design with CES 17.12 Exploring the science with CES Elements

387 388 388 390 392 395 396 401 404 405 405 406 407

Chapter 18 Heat, beat, stick and polish: manufacturing processes 18.1 Introduction and synopsis 18.2 Process selection in design 18.3 Process attributes: material compatibility 18.4 Shaping processes: attributes and origins

409 410 410 413 414

viii Contents 18.5 18.6 18.7 18.8 18.9 18.10 18.11 18.12 18.13 18.14

Joining processes: attributes and origins Surface treatment (finishing) processes: attributes and origins Estimating cost for shaping processes Computer-aided process selection Case studies Summary and conclusions Further reading Exercises Exploring design with CES Exploring the science with CES Elements

423 426 427 432 434 443 444 445 446 447

Chapter 19 Follow the recipe: processing and properties 19.1 Introduction and synopsis 19.2 Microstructure of materials 19.3 Microstructure evolution in processing 19.4 Processing for properties 19.5 Case studies 19.6 Making hybrid materials 19.7 Summary and conclusions 19.8 Further reading 19.9 Exercises 19.10 Exploring design with CES

449 450 450 454 462 464 472 474 475 476 477

Chapter 20 Materials, processes and the environment 20.1 Introduction and synopsis 20.2 Material consumption and its growth 20.3 The material life cycle and criteria for assessment 20.4 Definitions and measurement: embodied energy, process energy and end of life potential 20.5 Charts for embodied energy 20.6 Design: selecting materials for eco-design 20.7 Summary and conclusions 20.8 Appendix: some useful quantities 20.9 Further reading 20.10 Exercises 20.11 Exploring design with CES

479 480 480 483

Index

503

484 490 493 497 498 498 499 501

Preface Science-led or Design-led? Two approaches to materials teaching Most things can be approached in more than one way. In teaching this is especially true. The way to teach a foreign language, for example, depends on the way the student wishes to use it—to read the literature, say, or to find accommodation, order meals and buy beer. So it is with the teaching of this subject. The traditional approach to it starts with fundamentals: the electron, the atom, atomic bonding, and packing, crystallography and crystal defects. Onto this is built alloy theory, the kinetics of phase transformation and the development of microstructure on scales made visible by electron and optical microscopes. This sets the stage for the understanding and control of properties at the millimeter or centimeter scale at which they are usually measured. The approach gives little emphasis to the behavior of structures, methods for material selection, and design. The other approach is design-led. The starting point is the need: the requirements that materials must meet if they are to perform properly in a given design. To match materials to designs requires a perspective of the range of properties they offer and the other information that will be needed about them to enable successful selection. Once the importance of a property is established there is good reason to ‘drill down’, so to speak, to examine the science that lies behind it—valuable because an understanding of the fundamentals itself informs material choice and usage. There is sense in both approaches. It depends on the way the student wishes to use the information. If the intent is scientific research, the first is the logical way to go. If it is engineering design, the second makes better sense. This book follows the second.

What is different about this book? There are many books about the science of engineering materials and many more about design. What is different about this one? First, a design-led approach specifically developed to guide material selection and manipulation. The approach is systematic, leading from design requirements to a prescription for optimized material choice. The approach is illustrated by numerous case studies. Practice in using it is provided by Exercises. Second, an emphasis on visual communication and a unique graphical presentation of material properties as material property charts. These are a central feature of the approach, helpful both in understanding the origins of properties, their manipulation and their fundamental limits, as well as providing a tool for selection and for understanding the ways in which materials are used. Third, its breadth. We aim here to present the properties of materials, their origins and the way they enter engineering design. A glance at the Contents pages will show sections dealing with:

• Physical properties • Mechanical characteristics • Thermal behavior

x Preface • • • •

Electrical, magnetic and optical response Durability Processing and the way it influences properties Environmental issues

Throughout we aim for a simple, straightforward presentation, developing the materials science as far as is it helpful in guiding engineering design, avoiding detail where this does not contribute to this end. And fourth, synergy with the Cambridge Engineering Selector (CES)1—a powerful and widely used PC-based software package that is both a source of material and process information and a tool that implements the methods developed in this book. The book is self-contained: access to the software is not a prerequisite for its use. Availability of the CES EduPack software suite enhances the learning experience. It allows realistic selection studies that properly combine multiple constraints on material and processes attributes, and it enables the user to explore the ways in which properties are manipulated. The CES EduPack contains an additional tool to allow the science of materials to be explored in more depth. The CES Elements database stores fundamental data for the physical, crystallographic, mechanical, thermal, electrical, magnetic and optical properties of all 111 elements. It allows interrelationships between properties, developed in the text, to be explored in depth. The approach is developed to a higher level in two further textbooks, the first relating to mechanical design2, the second to industrial design3.

1

2

3

The CES EduPack 2007, Granta Design Ltd., Rustat House, 62 Clifton Court, Cambridge CB1 7EG, UK, www.grantadesign.com. Ashby, M.F. (2005), Materials Selection in Mechanical Design, 3rd edition, Butterworth-Heinemann, Oxford, UK, Chapter 4. ISBN 0-7506-6168-2. (A more advanced text that develops the ideas presented here in greater depth.) Ashby, M.F. and Johnson, K. (2002) Materials and Design—The Art and Science of Material Selection in Product Design, Butterworth-Heinemann, Oxford, UK. ISBN 0-7506-5554-2. (Materials and processes from an aesthetic point of view, emphasizing product design.)

Acknowledgements No book of this sort is possible without advice, constructive criticism and ideas from others. Numerous colleagues have been generous with their time and thoughts. We would particularly like to recognize suggestions made by Professors Mick Brown, Archie Campbell, Dave Cardwell, Ken Wallace and Ken Johnson, all of Cambridge University, and acknowledge their willingness to help. Equally valuable has been the contribution of the team at Granta Design, Cambridge, responsible for the development of the CES software that has been used to make the material property charts that are a feature of this book.

Resources that accompany this book Exercises Each chapter ends with exercises of three types: the first rely only on information, diagrams and data contained in the book itself; the second makes use of the CES software in ways that use the methods developed here, and the third explores the science more deeply using the CES Elements database that is part of the CES system.

Instructor’s manual The book itself contains a comprehensive set of exercises. Worked-out solutions to the exercises are freely available to teachers and lecturers who adopt this book. To access this material online please visit http://textbooks.elsevier.com and follow the instructions on screen.

Image Bank The Image Bank provides adopting tutors and lecturers with jpegs and gifs of the figures from the book that may be used in lecture slides and class presentations. To access this material please visit http://textbooks.elsevier.com and follow the instructions on screen.

The CES EduPack CES EduPack is the software-based package to accompany this book, developed by Michael Ashby and Granta Design. Used together, Materials: Engineering, Science, Processing and Design and CES EduPack provide a complete materials, manufacturing and design course. For further information please see the last page of this book, or visit www.grantadesign.com.

Chapter 1

Introduction: materials— history and character

Professor James Stuart, the first Professor of Engineering at Cambridge.

Chapter contents 1.1 1.2 1.3 1.4 1.5 1.6

Materials, processes and choice Material properties Design-limiting properties Summary and conclusions Further reading Exercises

2 4 9 10 10 10

2 Chapter 1 Introduction: materials—history and character

1.1

Materials, processes and choice Engineers make things. They make them out of materials. The materials have to support loads, to insulate or conduct heat and electricity, to accept or reject magnetic flux, to transmit or reflect light, to survive in often-hostile surroundings, and to do all this without damage to the environment or costing too much. And there is the partner in all this. To make something out of a material you also need a process. Not just any process—the one you choose has to be compatible with the material you plan to use. Sometimes it is the process that is the dominant partner and a material-mate must be found that is compatible with it. It is a marriage. Compatibility is not easily found—many marriages fail— and material failure can be catastrophi...