材料物理導(dǎo)論課件

Chapter1:Introduction,atomicstructureandbondingReferences《材料科學(xué)基礎(chǔ)》胡賡祥主編,上海交通大學(xué)出版社,（第二版）2006《MaterialsScienceandEngineering:AnIntroduction》editedbyWilliamD.Callister,Jr.,JohnWiley&Sons,Inc.《材料科學(xué)基礎(chǔ)》潘金生主編清華大學(xué)出版社《材料科學(xué)基礎(chǔ)》徐恒鈞主編北京工業(yè)大學(xué)出版社

《材料科學(xué)基礎(chǔ)》劉智恩主編西北工業(yè)大學(xué)出版社Outline:FundamentalconceptsinMaterialsScienceFoundationsThestatusofMaterialsScienceFoundationsWhystudyMaterialsScienceFoundationsContentsofMaterialsScienceFoundationsHowtolearnMaterialsScienceFoundationseffectively

1.1Fundamental

conceptsin

materialssciencefoundations

Materials

issynonymouswithsubstance,andisanythingmadeofmatter–hydrogen,airandwaterareallexamplesofmaterials.Materialsscience

isaninterdisciplinaryfieldinvolvingthepropertiesofmatteranditsapplicationstovariousareasofscienceandengineering.Materialssciencefoundations

isthebasictheoryofmaterialresearch,itinvestigatestherelationshipbetweenthestructureofmaterialsatatomicormolecularscalesandtheirmacroscopicproperties.

1.2Statusofmaterialsscience

Thedevelopmentandadvancementofsocietieshavebeen

intimatelytiedtothemembers’abilitytoproduceandmanipulatematerials.Thehumancivilizations

havebeen

designatedbytheleveloftheir

materialsdevelopment.StoneAge(2.5millionBC)BronzeAge(3000BC)IronAge(1000BC)CementAge(0BC)SteelAge(1800s)SiliconAge(1950s)NewMaterialsAge(1990s)1.3Whystudymaterialssciencefoundations

MaterialsScienceisaninterdisciplinaryfieldinvolvingphysics,chemistryandetc.Itinvestigatestherelationshipbetweenthestructureofmaterialsandtheirproperties.Therightsketchmapshowsusthefourelementsofthematerialsscienceandengineering.

1.Themeaningofmaterialsscience

Thestructureofmaterialsincludesdifferentcrystals,amphorousandmicrostructuresunderthemicroscope.Thepropertyofmaterialsincludesphysicalproperty,chemicalpropertyandmechanicalproperty.Theinternalstructureofmaterialsincludesfourlevels:(a)atomicstructure;(b)Bonding;(c)Atomicarrangement;(d)MicrostructureTherelationshipbetweenmaterialsanditsstructure

ThemaindifferencebetweenMaterialsScienceandMaterialsEngineeringisthattheirfocusisdifferent,However,thereisnoadefiniteborderlinebetweenthesetwosciences.Therefore,wealwaysputthemtogetherandcallitMaterialsScienceandEngineering(MRS).2.TherelationshipbetweenthematerialsscienceandmaterialsengineeringMaterialsSciencesTechniquePropertyStructureMaterialsEngineeringEquipmentTechniqueStructurePropertyComponentbehaviorMaterialsengineeringincludesthefollowingfiveparts:Materialssciencesincludesthefollowingthreeparts:ThefourelementsofMaterialsScienceandEngineeringStructure:includingmacrostructure,microstructure,atomicimageandelectronicstructure.Property:includingmechanicsproperty,physicalproperty,chemicalpropertyandmetallurgyprocessingproperty.Processing:includingthefabrication,processingandpost-treatmentofthematerials.Usagestatus:includingthestructuralstability,theenvironmentaleffectandthepropertychangesofthematerials.3.

Classificationofmaterial

Materialscanbeclassifiedintothestructuralmaterialsandfunctionalmaterialsaccordingtotheirstructureandusage.Thiscourseinvolvedthefollowingmaterialsincludingmetal,ceramic,macromolecularmaterialsandthecorrespondingcompounds.Metals:blackmetal(steel),colouredmetal(allmetals

excludingsteel)

Ceramics:oxideceramic,non-oxideceramics

Macromolecularmaterials:plastic,rubbersyntheticfiber

Compositematerials:metalcomposite,ceramiccomposite,

colophonycomposite.

Structuralmaterials:metal,ceramic,macromolecularMaterials

andthecorrespondingcomposites.Functionalmaterials:

electronicmaterials,photoelectricmaterials,superconductors,etc.metalCeramicCompositesMacromolecule4.MaterialsapplicationMaterialsandcomputer

(a)Removable

memorizerinpersonalcomputers(b)Computerdevelopment:electrontube→transistor→integratecircuit

TypeMaterialsStoragePropertyFloppydiskFerricoxide1.44MblowstoragecapacitydocumentfileformatCD-RWZnS650MbCD,lowprice,largeamountUsageMOTbFeCo650Mb,1.3GSpecialdrive,expensiveDVD-RWZnS4.7Gb(singlelayer)CD-RWandCD,largeamountUsageElectrontubeElectrodematerial:tungsten(W),molybdenum(Mo)AudionThispictureistakenfromNationalGeographicVol.162,No.4,1982IntegratecircuitMaterials:singlecrystalSi,highpurityTi,SiO2andCrthinfilmsSinglecrystalSistickSinglecrystalSiwaferIntegratecircuitsinglecrystalfurnaceMaterialsanddailyuseTitaniumBicycle

LifesciencematerialsBefore:Hgalloys(top)Newceramics(bottom)anti-acid,anti-suddencoldandantisuddenheatability,lowthermalconducutivity,comfortableetc.)

Compositematerials

Carbon,boronfiberandepoxycompoundfiberareallverylight,whichcanusedforenhancingthestrengthinsomespecialdirections.Aviationmaterials

Addingalloyingelementswillimprovethephysicalandmechanicalpropertiesoftheairplane’sbodymaterialssuchasstrength,endurance,usagelifetime.Supersteel

Properties:superhard,highstrength,beingabletousedfornewfabricationtechnique,anti-rustetc.1.4ContentsMaterialsmicrostructure

Atomsstructureandbonding,solidstatestructure,crystaldefects,atomicandmolecularmotionsinsolid,distortionandrecrystallization.Thelawofphasetransition

Phasetransitioninasingle-component,binaryandternarysystemsMaterialsform

Crystal,amphorousandmetastablematerialsMaterialsmetastablestateanditsphysicalproperties

Nanomaterials,Dielectricity,ferroelectricityandferromagnetismModernanalyticalmethodsinmaterials

X-raydiffraction(XRD),Transmissionelectronmicroscopy(TEM),Scanningelectronmicroscopy(SEM),Atomicforcemicroscopy(AFM)

Chapter2:Solidstructureandbasiccrystaltheory（FoundationofCrystallography）

IntroductionClassifiedaccordingthestateofthematerials:Gas,liquidandSolidClassifiedaccordingtothearrangementofatomormoleculeinmaterials:crystalandnon-crystal

Differencebetweenthecrystalandnon-crystal:

Atomicarrangements:

atomsincrystalsarespatiallyperiodicarrangedwhileatomsinnon-crystalarearrangedinanirregularwayMeltingpoint:

crystalshaveafixedmeltingpointwhilethenon-crystalshavenofixedmeltingpoint.Theliquid-solidtransitiontakeplaceinatemperaturerange.Anisotropy：Crystals:anisotropy;non-crystal:isotropy

Crystals:mostceramics,afewmacromolecularmaterials,metalsandalloys

Non-crystals:mostmacromolecularmaterials,glassandcomplexmaterials.2.1Foundationofcrystallography

1.SpacelatticeandunitcellLatticepoint:

Alatticepointisapointinacartesiancoordinatesystemsuchthatbothitsx-andy-coordinatesareintegers.Spacelattice:

A3-dimensionalgeometricarrangementoftheatoms.

Lattice:

Lattice

meansathree-dimensionalarrayofpointscoincidingwithatompositions.Unitcell:

theunitcell

isthebasicstructuralunitofthecrystalstructure.SketchmapofcrystallatticeSketchmapofunitcellUnitcellcharacterization

Characterizationofthesizeandshapeoftheunitcell:Thelengthofthecelledges

:a,bandc(latticeconstantsorparameters)Theanglesbetweenthecelledges:α、β、γ.Theprincipleofchoosingaunitcell:ItcanreflectthehighlysymmetryoftheoriginallatticeTheamountoftheequaledgesandanglesshouldbethelargestWhentheangleequals90degree,theamountoftherightangleshouldbethelargestIthastheminimumvolumeCharacterizationofunitcella,bandcα,βandγorusinglatticevectora,bandcruvW=ua+vb+wcV=a.(bxc)Simpleunitcell:

onlyonelatticepointateachcorneroftheparallelepipedComplexunitcell:

latticepointalsocanlocateatbodycenter,facecenterandbottomcenterbesidesthecornerSketchmapofthelattice

constantLatticetypeSevencrystal

systems,fourteenBravaislattice(seethetableonthenextslide)Thedifferenceofthecrystalstructureandspacelattice

Spacelattice：onlyhave14latticearrangement.

Crystalstructure：thearrangementoftheparticleisinfiniteSevencrystal

systemsandfourteenBravaislatticeCrystalsystemBravaislatticeCrystalsystemBravaislatticeTriclinica≠b≠c，α≠β≠γMonoclinica≠b≠c，α=γ=90o≠βOrthorhombica≠b≠c，α=β=γ＝90oSimpletriclinicSimplemonoclinicBottom-centeredmonoclinicSimpleorthorhombicBottom-centeredorthorhombicBody-centeredorthorhombicFace-centeredorthorhombicHexagonala1=a2＝a3≠c，α=β＝90o，γ=120oRhombohedrala=b=c,α=β=γ≠90oTetragonala=b≠c,α=β=γ＝90oCubica=b=c，α=β=γ＝90oSimplehexagonalSimpleRhombobedralSimpletetragonalBody-centeredtetragonalSimplecubicBody-centeredcubicFace-centeredcubicSimpletriclinic

a≠b≠cα≠β≠γBottom-centeredmonoclinic

a≠b≠cα=γ=90°≠βSimplemonoclinic

a≠b≠cα=γ=90°≠βSimpleorthorhombica≠b≠c，α=β=γ=90°Bottom-centeredorthorhombica≠b≠c，α=β=γ=90°Body-centeredorthorhombica≠b≠c，α=β=γ=90°Face-centeredorthorhombica≠b≠c，α=β=γ=90°Simplehexagonal

a=b≠c，α=β=90°，γ=120°

Simplerhombobedrala=b=c，α=β=γ≠90°

Simpletetragonala=b≠c，α=β=γ=90°

Body-centeredtetragonal

a=b≠c，α=β=γ=90°Simplecubic

a=b=c，α=β=γ=90°Body-centeredcubica=b=c，α=β=γ=90°Face-centeredcubic

a=b=c，α=β=γ=90°2.IndicesofdirectionsandIndicesofcrystalplaneCrystalplane:

oneofasetofparallel,equallyspacedplanesinacrystalstructure.Crystaldirection:

thecrystallographicdirectionsarefictitiouslineslinkingnodes(atoms,ionsormolecules)ofacrystal).

Indicesofdirectionsandindicesofcrystalplane(Millerindices):

anotationsystemincrystallographyforplanesanddirectionsincrystallattice.

2.1Foundationofcrystallography

a)IndicesofdirectionsinthecubiccrystalsystemsStepsofdeterminingtheindicesofdirections[uvw]incubiccrystalsystems:BuildingcoordinateSolvingcoordinateConvertingintoanintegerListingsquarebrackets[uvw],addingaminussignatthetopoftheindicesifthecoordinatevalueisnegative.ThecoordinateofeachlatticepointincubiccrystalsystemThesketchmapofdeterminingcrystaldirection[uvw]inthecubiccrystalsystemCommoncrystaldirections[uvw]inthecubiccrystalsystemb).IndicesofcrystalplaneinthecubiccrystalsystemsStepsofdeterminingtheindicesofcrystalplane(hkl)incubiccrystalsystems:BuildingcoordinateSolvinginterceptTakingreciprocalConvertingintoaninteger:h,k,lListingroundbrackets(hkl),addingaminussignatthetopoftheindicesiftheinterceptvalueisnegative.

Thesketchmapofcrystalplane(hkl)inthecubiccrystalsystemTwocrystalplanes(hkl)inthecubic

crystalsystemh≠k≠

l≠0，thenthereare24crystalplanes

3!×4=24，forexample：｛123｝(2)h≠k≠0ork≠

l≠0orh≠

l≠0,thenthereare12crystalplanes

3!／2!＝12，forexample:{112}(3)h=k=l，thenthereare4crystalplanes

3!／3!×4＝4，forexample:{111}h=0ork=0orl=0，thenthereare12crystalplanes

(3!／2)×4＝12，foeexample:{120}

h==k=0orh=l=0ork=l=0，thenthereare3crystalplanes

(3!／2!22)×4＝3，forexample:{100}

Numbersthecrystalplanesinthefamilyofcrystalplanes{hkl}c).Indicesofcrystaldirectionandcrystalplanein

thehexagonalcrystalsystem

Thedeterminingstepissameasthatofthecubiccrystalsystem,butwealwayschoosefourcoordinatestodenotetheindicesofthecrystaldirectioninthehexagonalcrystalsystem:a1、a2、a3、c,wherea1、a2、a3locatethesamebottomfaceandtheanglebetweenthemis120o(thec-axisorientationisnormaltothebottomface).

Indicesofcrystalplan（hkil),wherei=-（h+k）

Indicesofcrystaldirection[uvtw],wheret=-（u+v）MillerindexinthehexagonalcrystalsystemThreeaxisfouraxisa1，a2，ca1，a2，a3，c120°

120°

120°

（hkil)i=-(h+k)[uvtw]t=-(u+v)Thesketchmapofcrystaldirection(plane)inthehexagonalcrystalsystem[hkil]inthehexagonalcrystalsystemd).ZoneZone:

azoneisdefinedasagroupofcrystalfacesthatintersectinparalleledges.

Zonelaw:

therelationshipbetween[uvw]and（hkl）

inthesamezoneis：hu+kv+lw=0

Wecangetthe[uvw]or(hkl)accordingtothezonelaw.

e)．InterplanerspacingTheperpendiculardistancebetweensuccessiveparallelplanesofatomsinacrystal,itisdenotedwithd,h,k,l.CubicHexagonalRectangularcoordinates

Theaboveformulaisonlyforsimpleunitcell.Foracomplexsimple,weshouldconsidertheeffectoftheadditionalplanes.fcc:whenh,kandlarenotalloddoralleven

Hexagonalcrystalsystem：

Cubicrystalsystem：

Forexample{100},{110}

bcch+k+l=odd,

Forexample{100},{111}Whenh+2k=3n(n=0,1,2,3,……),I=oddForexample{0001}Theanglebetweenthenormalof（h1k1l1）planeand(h2k2l2)planeOrthorhombicCubicHexagonal3.Symmetryofthecrystal

Symmetry——thefundamentalpropertyofthecrystalSymmetryelementsPointgroup:32Spacegroup:230Micro-symmetryMacro-symmetrySymmetricaxis(n)1,2,3,4,6Symmetricplane(m)Symmetriccenter(i)Turn-inversionaxis1,2,3,4,6Slidingplane:a,b,c,n,dHelixaxis:21,31,32,41,

42,43,61,62,

63,64,652.1Foundationofcrystallography

Chapter2:Solidstructureandbasiccrystaltheory（Foundationofcrystallography）2.2Crystalstructureofthemetals

Metalsingeneralarecrystalatthesolidstate.Themetalliccrystalisbondedbymetallicbonding.Thecommoncrystalstructureofthemetals:

Face-centeredcubicsturctureA1orfccBody-centeredcubicstuctureA2orbccHexagonalclose—packedA3orhcp1.ThreetypicalmetalliccrystalstructuresHowtocharacterizetheunitcell:ThearrangementoftheatomsintheunitcellLatticeparametersThenumberoftheatomsintheunitcellTheradiusRoftheatomsCoordinativenumberanddensityClosed-packeddirectionandclosed-packedplaneIntersticeofthecrystalstructureThestackingmanneroftheatomsModelsofthethreetypicalmetalliccrystalstructuresThenumberofatomsintheunitcellofthreetypicalmetalliccrystalstructuresTheatomicradiusandlatticeparametersThestackingmannerofthepackedplanesofthetypicalmetalliclattice(a)hcpstructure(b)fccstructure(b)fcccrystalcell

a)Faced-centeredcubiclattice(properties)Thearrangementoftheatomsintheunitcell:thereisoneatomateachtopofthe8cornerandoneatomineachcenterofthe6faces.Latticeparameters:a=b=c；α=β=γ=90oThenumberofatomsintheunitcell:n=8×1/8＋6×1/2=4

TheatomicradiusR:halfofthedistancebetweenthetwotouchedatoms.Coordinativenumberanddensity:

CoordinativenumberCN=12Densityk=0.74Thelocationoftheatomsintheface-centeredcubiclatticeThenumberoftheatomsintheface-centeredcubiclatticeThecoordinativenumberoftheatomsintheface-centeredcubiclatticeThepackedplanesoftheface-centeredcubiclatticeTwotypesofinterstice:

tetrahedralintersticeandoctahedralinterstice

Octahedralinterstice:rB=0.414R，whererBistheradiusoftheinterstice,Ristheradiusoftheatomandthenumberoftheintersticeis4.

Tetrahedralinterstice:rB=0.225R，thenumberoftheintersticeis8.Thestackingmanner:ABCABC…orACBACB…Metalswithfccstructure:γ-Fe,Al,Cu,Ni,AuandAgetc.a)Faced-centeredcubiclattice(intersticeandthestackingmanner)

Octahedralintersticeoftheface-centeredcubiclatticeOctahedralintersticeOctahedralintersticeofthefaced-centeredcubiclatticeTetrahedralintersticeoftheface-centeredcubiclatticeTetrahedralintersticeTetrahedralintersticeofthefaced-centeredcubiclatticeThestackingmanneroftheatomsintheface-centeredcubiclatticeb)Body-centeredcubiclattice

(properties)Thearrangementoftheatoms:thereisoneatomateachtopofthe8cornerandoneatominthecenterofbody.Latticeparameters:a=b=c，α=β=γ=90oThenumberofatomsintheunitcell:n=8×1/8＋1=2Theradiusoftheatom:

Coordinativenumberanddensity:CoordinativenumberCN=8Densityk=0.68

Thelocationoftheatomsinthebody-centeredcubiclatticeThenumberoftheatomsinthebody-centeredcubiclatticeThepackedplanesofthebody-centeredcubiclatticeb)Body-centeredcubiclattice(intersticeandthestackingmanner)

Interstice:

Tetrahedralintersticeandoctahedralinterstice

Octahedralinterstice:

rB=0.154R(in<100>)orrB=0.633R(in<110>);Number=6

Tetrahedralinterstice:rB=0.291R;Number=6Stackingmanner:ABABAB…Metalswithbccstructure:α-Fe,δ-Fe,Cr,Mo,WandVetc.Intersticeofthebody-centeredcubiclatticeN=6N=12Octahedralinterstice

MetallicatomsOctahedralintersticeTetrahedralintersticeMetallicatomsTetrahedralintersticec)Hexagonalclose-packedlattice

(properties)

Thearrangementoftheatoms:thereisoneatomateachtopcornerofthehexagonalpilarandthreeatomsinthecenterofthehexagonalpilar.Latticeparameters:a1=a2≠a3，α=β=90o，γ=120oThenumberofatomsinthelattice：

n=12×1/6＋2×1/2＋3=6Theradiusoftheatom:2R=aR=a/2Coordinativenumberanddensity:CoordinativenumberCN=12Densityk=0.74

Thelocationoftheatomsinthehexagonalclose-packedlattice

Thenumberoftheatomsinthehexagonalclose-packedlattice

Thepackedplanesinthehexagonalclose-packedlattice

Thecoordinativenumberinthehexagonalclose-packedlattice

c)Hexagonalclose-packedlattice

(intersticeandthestackingmanner)

Interstice:complex

Octahedralinterstice:

rB=0.414R,N=6

Tetrahedralinterstice:rB=0.225R,N=12Stackingmanner:ABABAB…

Metalswithhcpstructure:Mg,Zn,BeandCdetc.Octahedralintersticeofthehexagonalclose-packedlattice

OctahedralintersticeMetallicatomsOctahedralintersticeTetrahedralintersticeofthehexagonalclose-packedlatticeTetrahedralintersticeMetallicatomsTetrahedralintersticeThestackingmanneroftheatomsinthehexagonalclose-packedlattice

2.Multi-crystalproperties

Multi-crystalpropertiesmeansthatsomemetalshavedifferentcrystalstructuresatdifferenttemperaturesandpressures.

Multi-crystaltransition(orallotropictransition)meansthattheinnerpartofthemetalwilltransferfromonestructuretoanotherstructurewhentheexternalconditionschanged(forexample,TandP).Forexample:3.AnisotropyofthecrystalAnisotropy:anisotropyisthepropertyofbeingdirectionallydependent.Crystalgrain:

particlesthatcomposedofthecrystal.Polycrystal:

polycrystallinematerialsaresolidsthatarecomposedofmanycrystallitesofvaryingsizeandorientation.

Crystalgrain

MultiphasealloysThemorphologyimageofalloysThefundamentalrequirementofthissectionNeedtomasterthefollowingconceptsandterms：IsotropyandanisotropyPropertiesofthreetypicalcrystalstructuresincludingtheshapeoftheunitcell,latticeparameters,thenumberoftheatomsintheunitcell,theradiusoftheatom,coordinativenumber,density,thesizeandnumberofdifferentintersticeaswellastheindicesoftheclose-packedplaneandtheclose-packeddirectionetc.

Polycrystalsandsinglecrystals,crystalgrainandgrainboundary.

Chapter2:Solidstructureandbasiccrystaltheory（Foundationofcrystallography）IntroductionAlloyanalloyisapartialorcompletesolidsolutionofoneormoreelementsinametallicmatrix.

Constituentelement:thefundamentalunitthatcomposedofthealloy.Itcanbemetals,nonmetalsandcompounds.Structurethemorphologyimageofthematerials.Itcanbeobservedbythenakedeye,themagnifier

ormicroscope.

Macro-structure:themorphologyimagethatcanbeobservedbythenakedeyeora30timesmagnifer.

Micro-structure:

themorphology

imagesunderthemicroscope.

PhaseUniformpartsinthealloyhavingthesamecondensedstate,samechemicalcomponent,samecrystalstructureandpropertiesaswellasbeingseparatedeachotherbytheinterface.2.3AlloyphasestructureSinglephasealloys：alloyscomposedwithonephaseMultiphasealloys：alloyscomposedwithseveraldifferentphasesThepropertiesofthealloyaredeterminedbythefollowingfactors:

(a)

Electrochemistry(electronegativityorchemicalappetency)

(b)thesizeoftheatom(c)theatomicvaluePhaseclassification:

solidsolutionandinterphase1.Solidsolution

Asolidsolutionisasolid-statesolutionofoneormoresolutesinasolvent.Suchamixtureisconsideredasolutionratherthanacompoundwhenthecrystalstructureofthesolventremainsunchangedbyadditionofthesolutes,andwhenthemixtureremainsinasinglehomogeneousphase.

Thedistinctpropertyofthesolidsolutioniskeepingthecrystalstructureofthesolvent.a).Classificationofthesolidsolution

Accordingtothelocationofthesoluteatomsinthelattice:

SubstitutionalsolidsolutionInterstitialsolidsolution

Accordingtothesolubilityofthesoluteatomsinthesolvent:

LimitedsolidsolutionUnlimittedsolidsolution

Accordingtodistributionofthesoluteatomsinthesolvent:

Non-orderedsolidsolutionOrderedsolidsolution

Accordingtothebodytype

：

Primarysolidsolution

SecondarysolidsolutionTwotypesofthesolidsolution

(substitutionorinterstice)Orderedsolidsolution-shortrangeOrderedsolidsolution-longrangeOrderedsolidsolution－segregation

b).SubstitutionsolidsolutionSubstitutionsolidsolutioningeneralisformedamongthemetalelements.Thesamecrystalstructureisthenecessaryconditionofformingtheunlimitedsolidsolution.Whenthesizeoftheatom△r<15%orr(solute)/r(solvent)>0.85,thesolubilityofthesolidsolutionwillbelargeunderotherconditionsisnearlysameandviceversa.

Forexample:

iron-basedalloys,unlimitedsolidsolution△r<8%。

copper-basedalloys,unlimitedsolidsolution△r<10%

Electronegativity

ElectronicdensityLarge-compoundSmall-solidsolutionLarge-interphaseSmall-solidsolutionThesketchmapofthesubstitutionsolidsolutionLatticeaberranceinducedbythelargeandsmallsoluteatomsinthesubstitutionsolidsolutionc).interstitialsolidsolution

Thesoluteatomsaresomenonmetalelementswiththeradiuslessthan0.1nm（C,N,O,H,B)

Formationcondition:△r>41%orr(solute)/r(solvent)><0.59interstitialsolidsolutioncanonlybelimittedsolidsolutionanditssolubilityissmall

Forexample:Catomsinα－Fe（max.Wt=0.0218%）

Catomsinγ－Fe（max.Wt=2.11%）Thesketchmapoftheinterstitialsolidsolution(1)Thesketchmapoftheinterstitialsolidsolution(2)Latticeaberranceinducedbythelargeandsmallsoluteatomsintheinterstitialsolidsolutiond).Themicrocosmicnonuniformofthesolid

solutionThedistributionofthesoluteatomsinthesolidsolutionisnotallunordered.Atgivenconditions,soluteatomsandsolventatomsaligninanorderandformtheorderedsolidsolution.Theratioofthesoluteatomswiththesolventatomsisafixedvalueanditcanbeexpressedbyachemicalmolecularformula.Theorderedsolidsolutionstructurecanbenamedassuperlattice.

Forexample:forCu-Alalloy,Cu:Al=1:1or3:1

orderedsuperlatticeCuAlorCu3Ale).PropertiesofthesolidsolutionChangesoflatticeparameters

Substitutionsolidsolution

：

rsolute>rsolvent，anincrease；rsolute<rsolvent，adecrease.

Interstitialsolidsolution：

aincreaseswiththedissolvingofthesolute.

Strengtheningofthesolidsolution.changesofthephysicalandchemicalproperties.2.interphase

Interphase:

Interphaseisanewphaseformedinthereactionamongtheelementsofthealloy,itcanbecompoundandcompound-basedsolidsolution.Thebondingmanneroftheatomsintheinterphase：

Mixtureofmetallicbondingandotherbonding.Theyhavethemetallicproperties.Forexample:

Fe3Cinsteel,CuAlincu-alalloy,NiTiandCuZninshapememoryalloy,etc.Classificationofinterphase：

Valence

compound,electroncompound,size-factorcompound(interstitialphase,interstitialcompound,TCPphase),superstructure.a).valencecompoundValencecompound:

includingsuchcompoundsformedbysomemetalsandelementswithlargerelectronegativityinⅥA,ⅤA,ⅣA.Forexample:ABtype(MgS,MnS,FeS),AB2(Mg2Pb,Mg2Sn)orA2Btype(Mg2Ge,Mg2Si),A3B2type.Valencecompoundhasveryhighandrigidityandbrittleness,whichcanenhancetherigidityandbrittlenessofthematerialsintheindustryalloys.

Forexample:

Mg2SiinAl-Mg-Sialloy.b).electroncompo