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: permissions@elsevier.
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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.com Typeset by Charon Tec Ltd (A Macmillan Company), Chennai, India.com Printed and bound in the UK 07 08 09 10 10 9 8 7 6 5 4 3 2 1 Contents Preface ix Acknowledgements xi Resources that accompany this book xii Chapter 1 Introduction: materials—history and character 1 1.1 Materials, processes and choice 2 1.3 Design-limiting properties 9 1.4 Summary and conclusions 10 1.6 Exercises 10 Chapter 2 Family trees: organizing materials and processes 13 2.1 Introduction and synopsis 14 2.2 Getting materials organized: the materials tree 14 2.3 Organizing processes: the process tree 18 2.4 Process–property interaction 21 2.5 Material property charts 22 2.6 Computer-aided information management for materials and processes 24 2.7 Summary and conclusions 25 2.10 Exploring design using CES 28 2.11 Exploring the science with CES Elements 28 Chapter 3 Strategic thinking: matching material to design 29 3.1 Introduction and synopsis 30 3.2 The design process 30 3.3 Material and process information for design 34 3.4 The strategy: translation, screening, ranking and documentation 36 3.5 Examples of translation 39 3.6 Summary and conclusions 43 3.9 Exploring design using CES 46 iv Contents Chapter 4 Stiffness and weight: density and elastic moduli 47 4.1 Introduction and synopsis 48 4.2 Density, stress, strain and moduli 48 4.3 The big picture: material property charts 56 4.4 The science: what determines density and stiffness? 58 4.5 Manipulating the modulus and density 69 4.6 Summary and conclusions 73 4.9 Exploring design with CES 77 4.10 Exploring the science with CES Elements 78 Chapter 5 Flex, sag and wobble: stiffness-limited design 81 5.1 Introduction and synopsis 82 5.2 Standard solutions to elastic problems 82 5.3 Material indices for elastic design 89 5.4 Plotting limits and indices on charts 95 5.6 Summary and conclusions 106 5.9 Exploring design with CES 109 5.10 Exploring the science with CES Elements 109 Chapter 6 Beyond elasticity: plasticity, yielding and ductility 111 6.1 Introduction and synopsis 112 6.2 Strength, plastic work and ductility: definition and measurement 112 6.3 The big picture: charts for yield strength 116 6.4 Drilling down: the origins of strength and ductility 118 6.6 Summary and conclusions 135 6.9 Exploring design with CES 138 6.10 Exploring the science with CES Elements 138 Chapter 7 Bend and crush: strength-limited design 141 7.1 Introduction and synopsis 142 7.2 Standard solutions to plastic problems 142 7.3 Material indices for yield-limited design 149 7.5 Summary and conclusions 158 7.6 Further reading 159 Contents v 7.8 Exploring design with CES 161 Chapter 8 Fracture and fracture toughness 163 8.1 Introduction and synopsis 164 8.2 Strength and toughness 164 8.3 The mechanics of fracture 166 8.4 Material property charts for toughness 172 8.5 Drilling down: the origins of toughness 174 8.6 Manipulating properties: the strength–toughness trade-off 178 8.7 Summary and conclusions 181 8.10 Exploring design with CES 183 8.11 Exploring the science with CES Elements 183 Chapter 9 Shake, rattle and roll: cyclic loading, damage and failure 185 9.1 Introduction and synopsis 186 9.2 Vibration and resonance: the damping coefficient 186 9.4 Charts for endurance limit 194 9.5 Drilling down: the origins of damping and fatigue 195 9.6 Manipulating resistance to fatigue 196 9.7 Summary and conclusions 198 9.10 Exploring design with CES 202 Chapter 10 Keeping it all together: fracture-limited design 203 10.1 Introduction and synopsis 204 10.2 Standard solutions to fracture problems 204 10.3 Material indices for fracture-safe design 205 10.5 Summary and conclusions 220 10.8 Exploring design with CES 224 Chapter 11 Rub, slither and seize: friction and wear 227 11.1 Introduction and synopsis 228 11.3 Charting friction and wear 229 11.4 The physics of friction and wear3 231 vi Contents 11.5 Design and selection: materials to manage friction and wear 235 11.6 Summary and conclusions 240 11.9 Exploring design with CES 243 Chapter 12 Agitated atoms: materials and heat 245 12.1 Introduction and synopsis 246 12.2 Thermal properties: definition and measurement 246 12.3 The big picture: thermal property charts 249 12.4 Drilling down: the physics of thermal properties 251 12.5 Manipulating thermal properties 257 12.6 Design to exploit thermal properties 258 12.7 Summary and conclusions 268 12.10 Exploring design with CES 271 12.11 Exploring the science with CES Elements 272 Chapter 13 Running hot: using materials at high temperatures 275 13.1 Introduction and synopsis 276 13.2 The temperature dependence of material properties 276 13.3 Charts for creep behavior 281 13.4 The science: diffusion and creep 284 13.5 Materials to resist creep 293 13.6 Design to cope with creep 296 13.7 Summary and conclusions 304 13.10 Exploring design with CES 308 13.11 Exploring the science with CES Elements 308 Chapter 14 Conductors, insulators and dielectrics 311 14.1 Introduction and synopsis 312 14.2 Conductors, insulators and dielectrics 313 14.3 Charts for electrical properties 317 14.4 Drilling down: the origins and manipulation of electrical properties 320 14.5 Design: using the electrical properties of materials 331 14.6 Summary and conclusions 338 14.9 Exploring design with CES 341 14.10 Exploring the science with CES Elements 343 Contents vii Chapter 15 Magnetic materials 345 15.1 Introduction and synopsis 346 15.2 Magnetic properties: definition and measurement 346 15.3 Charts for magnetic properties 351 15.4 Drilling down: the physics and manipulation of magnetic properties 353 15.5 Materials selection for magnetic design 358 15.6 Summary and conclusions 363 15.9 Exploring design with CES 365 15.10 Exploring the science with CES Elements 366 Chapter 16 Materials for optical devices 367 16.1 Introduction and synopsis 368 16.2 The interaction of materials and radiation 368 16.3 Charts for optical properties 373 16.4 Drilling down: the physics and manipulation of optical properties 375 16.6 Summary and conclusions 382 16.9 Exploring design with CES 384 16.10 Exploring the science with CES Elements 385 Chapter 17 Durability: oxidation, corrosion and degradation 387 17.1 Introduction and synopsis 388 17.2 Oxidation, flammability and photo-degradation 388 17.4 Making materials that resist oxidation 392 17.5 Corrosion: acids, alkalis, water and organic solvents 395 17.6 Drilling down: mechanisms of corrosion 396 17.8 Summary and conclusions 404 17.11 Exploring design with CES 406 17.12 Exploring the science with CES Elements 407 Chapter 18 Heat, beat, stick and polish: manufacturing processes 409 18.1 Introduction and synopsis 410 18.2 Process selection in design 410 18.3 Process attributes: material compatibility 413 18.4 Shaping processes: attributes and origins 414 viii Contents 18.5 Joining processes: attributes and origins 423 18.6 Surface treatment (finishing) processes: attributes and origins 426 18.7 Estimating cost for shaping processes 427 18.8 Computer-aided process selection 432 18.10 Summary and conclusions 443 18.13 Exploring design with CES 446 18.14 Exploring the science with CES Elements 447 Chapter 19 Follow the recipe: processing and properties 449 19.1 Introduction and synopsis 450 19.2 Microstructure of materials 450 19.3 Microstructure evolution in processing 454 19.4 Processing for properties 462 19.6 Making hybrid materials 472 19.7 Summary and conclusions 474 19.10 Exploring design with CES 477 Chapter 20 Materials, processes and the environment 479 20.1 Introduction and synopsis 480 20.2 Material consumption and its growth 480 20.3 The material life cycle and criteria for assessment 483 20.4 Definitions and measurement: embodied energy, process energy and end of life potential 484 20.5 Charts for embodied energy 490 20.6 Design: selecting materials for eco-design 493 20.7 Summary and conclusions 497 20.8 Appendix: some useful quantities 498 20.11 Exploring design with CES 501 Index 503 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 mil- limeter 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 sec- ond 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.
