Mechanical Properties of Engineered Materials (Mechanical Engineering (Marcell Dekker))

584 Pages·2003·6.3 MB·English

by  Wole Soboyejo

Mechanical
Properties of
Engineered
Materials
Wolé Soboyejo
Princeton University
Princeton, New Jersey
Marcel Dekker, Inc. New York Basel
•
Copyright ©2002 by Marcel Dekker,Inc. All Rights Reserved.
Copyright © 2003 Marcel Dekker, Inc.
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Preface
Myprimaryobjectiveinthisbookistoprovideasimpleintroductiontothe
subject of mechanical properties of engineered materials for undergraduate
and graduate students. I have been encouraged in this task by my students
and many practicing engineers with a strong interest in the mechanical
properties of materials and I hope that this book will satisfy their needs. I
have endeavored to cover only the topics that I consider central to the
developmentofabasicunderstandingofthemechanicalpropertiesofmate-
rials. It is not intended to be a comprehensive review of all the different
aspects of mechanical properties; such a task would be beyond the capabil-
ities of any single author. Instead, this book emphasizes the fundamental
conceptsthatmustbemasteredbyanyundergraduateorgraduateengineer
before he or she can effectively tackle basic industrial tasks that require an
understandingofmechanicalproperties.Thisbookisintendedtobridgethe
gap between rigorous theory and engineering practice.
Thebookcoversessentialprinciplesrequiredtounderstandandinter-
pret the mechanical properties of different types of materials (i.e., metals,
ceramics,intermetallics,polymers,andtheircomposites).Basicconceptsare
discussedgenerically,exceptincaseswheretheyapplyonlytospecifictypes/
classes ofmaterials.Followingabrief introductiontomaterialsscienceand
basic strength of materials, the fundamentals of elasticity and plasticity are
presented, prior to a discussion of strengthening mechanisms (including
composite strengthening concepts). A simple introduction to the subject
of fracture mechanics is then presented along with fracture and toughening
mechanismsandadescriptionoftheeffectsoffatigueandtheenvironment.
Copyright © 2003 Marcel Dekker, Inc.
The book concludes with an overview of time-dependent viscoelastic/visco-
plasticbehavior,creep, and creepcrackgrowthphenomena.Wherever pos-
sible,thetextisillustratedwithworkedexamplesandcasestudiesthatshow
how to apply basic principles to the solution of engineering problems.
This book has been written primarily as a text for a senior under-
graduate course or first-level graduate course on mechanical properties of
materials.However,Ihopethatitwillalsobeusefultopracticingengineers,
researchers,andotherswhowanttodevelopaworkingunderstandingofthe
basicconceptsthatgovernthemechanicalpropertiesofmaterials.Toensure
a wide audience, I have assumed only a basic knowledge of algebra and
calculus in the presentation of mathematical derivations. The reader is also
assumedtohaveasophomore-levelunderstandingofphysicsandchemistry.
Prior knowledge of basic materials science and strength of materials con-
cepts is not assumed, however. The better-prepared reader may, therefore,
skim through some of the elementary sections in which these concepts are
introduced.
Finally, I would like to acknowledge a number of people that have
supported me over the years. I am grateful to my parents, Alfred and
Anthonia, for the numerous sacrifices that they made to provide me with
a good education. I am indebted to my teachers, especially John Knott,
Anthony Smith, David Fenner, and Stan Earles, for stimulating my early
interest in materials and mechanics. I am also thankful to my colleagues in
the field of mechanical behavior who have shared their thoughts and ideas
withmeovertheyears.Inparticular,IamgratefultoFrankMcClintockfor
hiscriticalreviewofthefirstfivechapters,andhissuggestionsforthebook
outline.
Ialsothankmycolleaguesinthemechanicalbehaviorcommunityfor
helping me to develop my basic understanding of the subject over the past
15 years. I am particularly grateful to Anthony Evans, John Hutchinson,
Paul Paris, Robert Ritchie, Richard Hertzberg, Gerry Smith, Ali Argon,
Keith Miller, Rod Smith, David Parks, Lallit Anand, Shankar Sastry,
Alan Needleman, Charlie Whitsett, Richard Lederich, T. S. Srivatsan,
Pranesh Aswath, Zhigang Suo, David Srolovitz, Barrie Royce, Noriko
Katsube, Bob Wei, Campbell Laird, Bob Hayes, Rajiv Mishra, and many
others who have shared their understanding with me in numerous discus-
sions over the years.
Iamindebtedtomypastandpresentstaffscientistsandpostdoctoral
research associates (Chris Mercer, Seyed Allameh, Fan Ye, Pranav
Shrotriya, and Youlin Li) and personal assistants (Betty Adam, Alissa
Horstman, Jason Schymanski, Hedi Allameh, and Yingfang Ni) for their
assistancewiththepreparationofthetextandfigures.BettyAdamdeserves
Copyright © 2003 Marcel Dekker, Inc.
special mention since she helped put the book together. I simply cannot
imagine how this project could have been completed without her help.
I am grateful to my students and colleagues at Princeton University,
MIT, and The Ohio State University who have provided me with a stimu-
lating working environment over the past few years. In particular, I thank
Lex Smits, my current department chair, and all my colleagues. My inter-
actions with colleagues and students have certainly been vital to the devel-
opment of my current understanding of the mechanical behavior of
materials.
Partialfinancialsupportforthepreparationofthisbookwasprovided
bytheNationalScienceFoundation(DMR0075135andDMR9458018).I
would like to thank the Program Managers, Dr. Bruce McDonald and Dr.
K. L. Murty, for providing the financial support and encouragement that
madethis book possible. Appreciation isalso extendedtoProf. TomEager
and Prof. Nam Suh of MIT for inviting me to spend a sabbatical year as
Visiting Martin Luther King Professor in the departments of Materials
Science and Engineering and Mechanical Engineering at MIT. The sabba-
tical year (1997–1998) at MIT provided me with a stimulating environment
for the development of the first few chapters of this book.
IalsothankDawnWechsler,JanetSachs,ElizabethCurione,andRita
Lazzazzaro of Marcel Dekker, Inc., for their patience and understanding.
Thisprojectwouldcertainlynothavebeencompleted(byme)withouttheir
vision, patience, and encouragement.
Finally,Ithankmywife,Morenike,forgivingmethefreedomandthe
timetowritethisbook.ThiswastimethatIshouldhavespentwithherand
ouryoungfamily.However,asalways,shewassupportiveofmywork,and
I know that this book could have never been completed without her fore-
bearance and support.
Wole´ Soboyejo
Copyright © 2003 Marcel Dekker, Inc.
Contents
Preface
1OverviewofCrystal/DefectStructureandMechanicalProperties
andBehavior
1.1Introduction
1.2AtomicStructure
1.3ChemicalBonds
1.4StructureofSolids
1.5StructuralLengthScales:Nanostructure,Microstructure,
andMacrostructure
1.6Summary
Bibliography
2DefectStructureandMechanicalProperties
2.1Introduction
2.2IndicialNotationforAtomicPlanesandDirections
2.3Defects
2.4ThermalVibrationsandMicrostructuralEvolution
2.5OverviewofMechanicalBehavior
2.6Summary
Copyright © 2003 Marcel Dekker, Inc.
Bibliography
3BasicDefinitionsofStressandStrain
3.1Introduction
3.2BasicDefinitionsofStress
3.3BasicDefinitionsofStrain
3.4Mohr’sCircleofStressandStrain
3.5ComputationofPrincipalStressesandPrincipalStrains
3.6HydrostaticandDeviatoricStressComponents
3.7StrainMeasurement
3.8MechanicalTesting
3.9Summary
Bibliography
4IntroductiontoElasticBehavior
4.1Introduction
4.2ReasonsforElasticBehavior
4.3IntroductiontoLinearElasticity
4.4TheoryofElasticity
4.5IntroductiontoTensorNotation
4.6GeneralizedFormofLinearElasticity
4.7StrainEnergyDensityFunction
4.8Summary
Bibliography
5IntroductiontoPlasticity
5.1Introduction
5.2PhysicalBasisforPlasticity
5.3Elastic–PlasticBehavior
5.4EmpiricalStress–StrainRelationships
5.5ConsidereCriterion
5.6YieldingUnderMultiaxialLoading
5.7Introductionto J DeformationTheory
2
5.8FlowandEvolutionaryEquations
(ConstitutiveEquationsofPlasticity)
5.9Summary
Copyright © 2003 Marcel Dekker, Inc.
Bibliography
6IntroductiontoDislocationMechanics
6.1Introduction
6.2TheoreticalShearStrengthofaCrystallineSolid
6.3TypesofDislocations
6.4MovementofDislocations
6.5ExperimentalObservationsofDislocations
6.6StressFieldsAroundDislocations
6.7StrainEnergies
6.8ForcesonDislocations
6.9ForcesBetweenDislocations
6.10ForcesBetweenDislocationsandFreeSurfaces
6.11Summary
Bibliography
7DislocationsandPlasticDeformation
7.1Introduction
7.2DislocationMotioninCrystals
7.3DislocationVelocity
7.4DislocationInteractions
7.5DislocationBowingDuetoLineTension
7.6DislocationMultiplication
7.7ContributionsfromDislocationDensityto
MacroscopicStrain
7.8CrystalStructureandDislocationMotion
7.9CriticalResolvedShearStressandSlipinSingle
Crystals
7.10SlipinPolycrystals
7.11GeometricallyNecessaryandStatisticallyStored
Dislocations
7.12DislocationPile-UpsandBauschingerEffect
7.13MechanicalInstabilitiesandAnomalous/Serrated
Yielding
7.14Summary
Bibliography
Copyright © 2003 Marcel Dekker, Inc.
8DislocationStrengtheningMechanisms
8.1Introduction
8.2DislocationInteractionswithObstacles
8.3SolidSolutionStrengthening
8.4DislocationStrengthening
8.5GrainBoundaryStrengthening
8.6PrecipitationStrengthening
8.7DispersionStrengthening
8.8OverallSuperposition
8.9Summary
Bibliography
9IntroductiontoComposites
9.1Introduction
9.2TypesofCompositeMaterials
9.3Rule-of-MixtureTheory
9.4DeformationBehaviorofUnidirectionalComposites
9.5MatrixversusCompositeFailureModesin
UnidirectionalComposites
9.6FailureofOff-AxisComposites
9.7EffectsofWhisker/FiberLengthonComposite
StrengthandModulus
9.8ConstituentandCompositeProperties
9.9StatisticalVariationsinCompositeStrength
9.10Summary
Bibliography
10FurtherTopicsinComposites
10.1Introduction
10.2UnidirectionalLaminates
10.3Off-AxisLaminates
10.4MultiplyLaminates
10.5CompositePlyDesign
10.6CompositeFailureCriteria
10.7ShearLagTheory
10.8TheRoleofInterfaces
10.9Summary
Copyright © 2003 Marcel Dekker, Inc.