Engineering Materials 2, Third Edition: An Introduction to Microstructures, Processing and Design (International Series on Materials Science and Technology) (v. 2)

467 Pages·2005·9.31 MB·English

by  Michael F. Ashby

Engineering Materials 2
An Introduction to Microstructures, Processing and Design
This Page is Intentionally Left Blank
Engineering Materials 2
An Introduction to Microstructures,
Processing and Design
Third Edition
Michael F. Ashby
and
David R. H. Jones
Department of Engineering, Cambridge University, UK

AMSTERDAM•BOSTON•HEIDELBERG•LONDON•NEWYORK•OXFORD
PARIS•SANDIEGO•SANFRANCISCO•SINGAPORE•SYDNEY•TOKYO
Butterworth-HeinemannisanimprintofElsevier
Butterworth-HeinemannisanimprintofElsevier
LinacreHouse,JordanHill,OxfordOX28DP
30CorporateDrive,Suite400,Burlington,MA01803
Firstedition1986
Reprintedwithcorrections1988
Reprinted1989,1992
Secondedition1998
Reprinted1999,2000,2001
Thirdedition2006
Copyright©2006,MichaelF.AshbyandDavidR.H.Jones.
Allrightsreserved
TherightsofMichaelF.AshbyandDavidR.H.Jonestobeidentifiedas
theauthorsofthisworkhasbeenassertedinaccordancewiththeCopyright,
DesignsandPatentsAct1988
Nopartofthispublicationmaybereproducedinanymaterialform(including
photocopyingorstoringinanymediumbyelectronicmeansandwhether
ornottransientlyorincidentallytosomeotheruseofthispublication)without
thewrittenpermissionofthecopyrightholderexceptinaccordancewiththe
provisionsoftheCopyright,DesignsandPatentsAct1988orunderthetermsof
alicenceissuedbytheCopyrightLicensingAgencyLtd,90TottenhamCourtRoad,
London,EnglandW1T4LP.Applicationsforthecopyrightholder’swritten
permissiontoreproduceanypartofthispublicationshouldbeaddressed
tothepublisher
PermissionsmaybesoughtdirectlyfromElsevier’sScienceandTechnologyRights
DepartmentinOxford,UK;phone:[phone];fax:[phone];
e-mail:[e-mail]queston-linevia
theElsevierSciencehomepage(http://www.elsevier.com),byselecting‘CustomerSupport’
andthen‘ObtainingPermissions’
BritishLibraryCataloguinginPublicationData
AcataloguerecordforthisbookisavailablefromtheBritishLibrary
LibraryofCongressCataloguinginPublicationData
AcataloguerecordforthisbookisavailablefromtheBritishLibrary
ISBN–13:978-0-7506-6381-6
ISBN–10:0-7506-6381-2
ForinformationonallButterworth-Heinemannpublications
pleasevisitourwebsiteathttp://www.books.elsevier.com

PrintedandboundinUK
06 07 08 09 10 10 9 8 7 6 5 4 3 2 1
Working together to grow
libraries in developing countries
www.elsevier.com | www.bookaid.org | www.sabre.org
Contents
General introduction ix
A. Metals 1
1. Metals 3
the generic metals and alloys; iron-based, copper-based, nickel-based,
aluminium-based and titanium-based alloys; design data; examples
2. Metal structures 14
the range of metal structures that can be altered to get different properties:
crystal and glass structure, structures of solutions and compounds, grain
and phase boundaries, equilibrium shapes of grains and phases; examples
3. Equilibrium constitution and phase diagrams 25
how mixing elements to make an alloy can change their structure; examples:
the lead–tin, copper–nickel and copper–zinc alloy systems; examples
4. Case studies in phase diagrams 35
choosing soft solders; pure silicon for microchips; making bubble-free ice;
examples
5. The driving force for structural change 48
the work done during a structural change gives the driving force for the
change; examples: solidification, solid-state phase changes, precipitate

coarsening, grain growth, recrystallisation; sizes of driving forces; examples
6. Kinetics of structural change: I – diffusive transformations 61
why transformation rates peak – the opposing claims of driving force and
thermal activation; why latent heat and diffusion slow transformations
down; examples
7. Kinetics of structural change: II – nucleation 74
how new phases nucleate in liquids and solids; why nucleation is helped by
solid catalysts; examples: nucleation in plants, vapour trails, bubble
chambers and caramel; examples
v
vi Contents
8. Kinetics of structural change: III – displacive transformations 83
how we can avoid diffusive transformations by rapid cooling; the
alternative – displacive (shear) transformations at the speed of sound;
examples
9. Case studies in phase transformations 97
artificial rain-making; fine-grained castings; single crystals for
semiconductors; amorphous metals; examples
10. The light alloys 108
where they score over steels; how they can be made stronger: solution, age
and work hardening; thermal stability; examples
11. Steels: I – carbon steels 122
structures produced by diffusive changes; structures produced by displacive
changes (martensite); why quenching and tempering can transform the
strength of steels; the TTT diagram; examples
12. Steels: II – alloy steels 135
adding other elements gives hardenability (ease of martensite formation),
solution strengthening, precipitation strengthening, corrosion resistance,
and austenitic (f.c.c.) steels; examples
13. Case studies in steels 144
metallurgical detective work after a boiler explosion; welding steels
together safely; the case of the broken hammer; examples
14. Production, forming and joining of metals 155
processing routes for metals; casting; plastic working; control of grain size;
machining; joining; surface engineering; examples
B. Ceramics and glasses 173
15. Ceramics and glasses 175
the generic ceramics and glasses: glasses, vitreous ceramics, high-technology
ceramics, cements and concretes, natural ceramics (rocks and ice), ceramic
composites; design data; examples
16. Structure of ceramics 183
crystalline ceramics; glassy ceramics; ceramic alloys; ceramic
micro-structures: pure, vitreous and composite; examples
17. The mechanical properties of ceramics 193
high stiffness and hardness; poor toughness and thermal shock resistance;
the excellent creep resistance of refractory ceramics; examples
Contents vii
18. The statistics of brittle fracture and case study 202
how the distribution of flaw sizes gives a dispersion of strength: the
Weibull distribution; why the strength falls with time (static fatigue);
case study: the design of pressure windows; examples
19. Production, forming and joining of ceramics 213
processing routes for ceramics; making and pressing powders to shape;
working glasses; making high-technology ceramics; joining ceramics;
applications of high-performance ceramics; examples
20. Special topic: cements and concretes 227
historical background; cement chemistry; setting and hardening of
cement; strength of cement and concrete; high-strength cements; examples
C. Polymers and composites 239
21. Polymers 241
the generic polymers: thermoplastics, thermosets, elastomers, natural
polymers; design data; examples
22. The structure of polymers 251
giant molecules and their architecture; molecular packing: amorphous or
crystalline?; examples
23. Mechanical behaviour of polymers 262
how the modulus and strength depend on temperature and time; examples
24. Production, forming and joining of polymers 279
making giant molecules by polymerisation; polymer “alloys”; forming and
joining polymers; examples
25. Composites: fibrous, particulate and foamed 289
how adding fibres or particles to polymers can improve their stiffness,
strength and tou ghness; why foams are good for absorbing energy;
examples
26. Special topic: wood 306
one of nature’s most successful composite materials; examples
D. Designing with metals, ceramics, polymers and composites 317
27. Design with materials 319
the design-limiting properties of metals, ceramics, polymers and
composites; design methodology; examples
viii Contents
28. Case studies in design 326
1. Designing with metals: conveyor drums for an iron ore terminal
2. Designing with ceramics: ice forces on offshore structures
3. Designing with polymers: a plastic wheel
4. Designing with composites: materials for violin bodies
29. Engineering failures and disasters – the ultimate test of design 352
Introduction
Case study 1: the Tay Bridge railway disaster – 28 December 1879
Case study 2: the Comet air disasters – 10 January and 8 April 1954
Case study 3: the Eschede railway disaster – 5 June 1998
Case study 4: a fatal bungee-jumping accident
Appendix 1 Teaching yourself phase diagrams 380
Appendix 2 Symbols and formulae 434
References 442
Index 445
General introduction
Materialsareevolvingtodayfasterthanatanytimeinhistory.Industrialnations
regard the development of new and improved materials as an “underpinning
technology” – one which can stimulate innovation in all branches of engineer-
ing, making possible new designs for structures, appliances, engines, electrical
and electronic devices, processing and energy conservation equipment, and
much more. Many of these nations have promoted government-backed initia-
tives to promote the development and exploitation of new materials: their lists
generally include “high-performance” composites, new engineering ceramics,
high-strength polymers, glassy metals, and new high-temperature alloys for gas
turbines.Theseinitiativesarenowbeingfeltthroughoutengineering,andhave
alreadystimulateddesignofanewandinnovativerangeofconsumerproducts.
So the engineer must be more aware of materials and their potential than
ever before. Innovation, often, takes the form of replacing a component made
of one material (a metal, say) with one made of another (a polymer, perhaps),
and then redesigning the product to exploit, to the maximum, the potential
offered by the change. The engineer must compare and weigh the properties
of competing materials with precision: the balance, often, is a delicate one. It
involves an understanding of the basic properties of materials; of how these
are controlled by processing; of how materials are formed, joined and finished;
and of the chain of reasoning that leads to a successful choice.
This book aims to provide this understanding. It complements our other
book on the properties and applications of engineering materials,∗ but it is not
necessary to have read that to understand this. In it, we group materials into
fourclasses:Metals,Ceramics,PolymersandComposites,andweexamineeach
in turn. In any one class there are common underlying structural features (the
long-chain molecules in polymers, the intrinsic brittleness of ceramics, or the
mixed ma terials of composites) which, ultimately, determine the strengths and
weaknesses(the“design-limiting”properties)ofeachintheengineeringcontext.
And so, as you can see from the Contents list, the chapters are arranged in
groups,withagroupofchapterstodescribeeachofthefourclassesofmaterials.
Ineachgroupwefirstintroducethemajorfamiliesofmaterialsthatgotomake
up each materials class. We then outline the main microstructural features of
theclass,andshowhowtoprocessortreatthemtogetthestructures(really,in
the end, the properties) that we want. Each group of chapters is illustrated by
∗
M.F.AshbyandD.R.H.Jones,EngineeringMaterials1:AnIntroductiontotheirPropertiesandApplications,
2ndedition,Butterworth-Heinemann,1996.
ix