材料科学概论

.,IntroductiontoMaterialsScienceandEngineering,GuanRui-fang,.,.,材料与新技术革命,.,.,.,.,.,材料与国防现代化,.,ThisbookisdividedintofourmajorsectionsThefundamentalsThestructuralmaterialsTheelectronicandmagneticmaterialsMaterialsinengineeringdesign,.,Natureofmaterialsproperties,Microscopicorsubmicroscopicstructure,Engineeringdesign,.,ChapterIMaterialsforEngineering,1.1Typesofmaterials1.2Fromstructuretoproperties1.3Selectionofmaterials1.4Materialsscienceandengineering,.,Keyword,Alloy5AlCiAtomic-scale-architectureBrittle5britlCeramicsi5rAmikComposite5kCmpEzit,-zaitConcrete5kCnkri:tConductorCrystalline5kristElainadj.Devitrifieddi:5vitrifaiDuctilitydQk5tilitiElectronicandmagneticmaterialElement5elimEntFiberglass5faIbElB:s,.,GlassGlass-ceramicInsulatorMaterialsscienceandengineeringMaterialsselectionMetallicMicrocircuitry5maIkrEJs:kItMicroscopic-scalearchitectureNoncrystallineNonmetallic5nCnmi5tAlik,Keyword,.,OxidePeriodicpiEri5CdiktablePlasticPolyethylene7pCli5eWili:nPolymerPropertyRefractorySemiconductorSilica硅石，SiO2Silicate硅酸盐Silicon硅元素Steel,Structuralmaterialwood,Keyword,.,1.1Typesofmaterials,a.Metalsmetallicbondb.Ceramics(glass)ionicaI5RnIkandcovalentkEu5veilEntbondc.PolymerscovalentandVanderwaalsbondd.Compositese.semiconductors,Whatmaterialsareavailabletome?,Fivecategories,.,.,AMetals,超塑性的,超塑性材料(制)的,1.i.e.,Latin，thewrittenabbreviationforidest,也就是，即。读作：thatis,2.state-of-the-art,技术发展水平，现代化的。,3.superplastic.,.,Characteristics(metallic金属的，金属性的)Itisstrongandcanbereadilyformedintopracticalshapes.Ductile5dQktailpermanentdeformabilitymetalliclusterelectricconductorMetalshavenobrittlenessandaresafeformanyapplications.,Structuralsteel,.,Gasket5Askit垫圈,衬垫,spring,wire,ValvevAlv,.,.,.,BCeramicssi5rAmiks,Ahomogeneousmixtureoftwoormoresubstances,whichmaybesolids,liquids,gases,oracombinationofthese.,1.Refractoryri5frAktEri,Difficulttomeltorwork;resistanttoheat.,2.fracturetoughness,断裂韧度,3.crystalline5kristElain,Being,relatingto,orcomposedofcrystalorcrystals.,4.Devitrifydi:5vitrifai,Tocause(aglassymaterial)tobecomecrystallineandbrittle.,5.solution,.,TheceramicsisderivedfromGreekword“keramic”whichmeansanartofpotter.Include:glass;enamelsi5nAmEl;refractories;cements;limes;plasters(plasterofParis);cermets5sE:met金属陶瓷,含陶合金;electronicceramics;highandlowtensionelectricalinsulators;structuralclayproducts;nuclearceramics;whitewares;abrasivesE5breisiv.,.,TheDifferentColorsofCorundumkE5rQndEm,Ruby,Sapphire5sAfaiE,.,WhyshouldntAl2O3bechosenforcertainapplicationswheremetallicaluminumhasbeenused?,1、Al2O3havetwoadvantages:,first,chemicallystable;,Aloxidized,second,highermeltingpoint(20200C),Al(6600C),refractory,useinindustrialfurnaceconstruction,.,Questions,Whatmaterialsareavailabletoyouinthisbook?Whatfundamentalcharacteristicsmetalshave?Pleaseshademetallicelementsinperiodictableandgivesomeexamplesofalloys.PleaselisttwoprincipaladvantagesofAl2O3relativetometallicAl.Whatsthemostlimitingpropertyofceramics.,.,Themostlimitingpropertyofceramics,brittleness,Recentdevelopmentinceramictechnologyareexpandingtheutilityofceramicsforstructuralapplicationnotbyeliminatingtheirinherentbrittleness,butbyincreasingtheirstrengthtosufficientlyhighlevels(greaterthan700MPa)andincreasingtheirresistancetofracture.,.,2、Al2O3MgOSiO2Si3N4,Atleastonemetallicelement+oneoffivenonmetalelement(C,N,O,PandS)Carbide5kB:baidNitride5naitraidOxide5CksaidPhosphide5fCsfaidSulphide.5sQlfaid,Oxideceramics,Nonoxideceramics,.,3、Onemetallicelementplusoneoffivenonmetallicelements(C,N,O,P,orS),.,4、Characteristics:,refractory,highhardness,highstrength,highbrittleness,.,.,.,Thesimilarstructuralfeatureofmetalsandceramics:Crystalline:theirconstituentatomsarestackedtogetherinaregular,repeatingpattern.Thedistinction:ceramicscanbemadeinanoncrystallineform.,skI5mAtIk,.,SiO2(approximately72%)Na2OCaO,Glass:,brittleness,similarwithcrystallineceramic,.,Glass-ceramicsisathirdcategoryLithiumaluminosilicatesCertainglasscompositionscanbefullydevitifiedbyanappropriatethermaltreatment,low-thermalexpansioncoefficients,complexforms,highmechanicalstrength,Vitreous5vItrIEs,glassystate,Subsequentcrystallization,.,.,CPolymers(plastics),Exempligratia.Forexample.,1.ethylene,Acolorless,flammablegas,C2H4,derivedfromnaturalgasandpetroleumandusedasasourceofmanyorganiccompounds,inwelding5weldiN焊接andcuttingmetals,andasananesthetic7Anis5Wetik麻醉剂.,2.polyethylene,Apolymerizedethyleneresin,usedespeciallyforcontainers,kitchenware,andtubing,orintheformoffilmsandsheetsforpackaging.,3.e.g.,.,Anyofnumerousorganiccompounds,suchasbenzeneandmethane,thatcontainonlycarbonandhydrogen.,4.AcrylicsE5kriliks,丙烯酸树脂,5.Nylon5nailEn,Anyofafamilyofhigh-strength,resilientsyntheticpolymers,themoleculesofwhichcontaintherecurringamidegroupCONH.,6.Hydrocarbon,.,Theseman-madematerialsareabranchoforganicchemistry.,.,.,1.Poly+mer:merinapolymerisasinglehydrocarbonmoleculesuchasethylene(C2H4).longchainolecules:Polymersarelong-chainmoleculescomposedofmanymersbondtogether.,.,.,1)nobrittleness,2.Characteristics:,2)lowermeltingpoint,3)highstrengthalongitschainandlowstrengthbetweenitschains,4)lightweightlow-cost,5)higherchemicalreactivity,6)Man-madematerials,.,Substitutionfortraditionalstructuralmetals,.,Qustions,pleaseillustratetwotypeofelementsthatcomposedceramiccompoundsinperiodictable.Whatarethemajorcompositionsofglass?whyglassesareimportantengineeringmaterials?Pleaselisttwocategoriesandgivesomeexamplesofceramicsaccordingtheircompositions.Pleaselistthreecategoriesandgivesomeexamplesofceramicsaccordingtheiratomicstructrualfeature.Whatarepolymers?Whatarecharacteristicsofpolymers?Pleasegivesomeexamplesofpolymers.,.,.,SiO2(approximately72%)Na2OCaO,Glass:,brittleness,similarwithcrystallineceramic,.,Accordingtotheircompositions,ceramicscanbedividedintotwocatogories.Oneisoxideceramicssuchasaluminumoxide(Al2O3),magnesiumoxide(MgO),andsilica(SiO2),theotheroneisnonoxideceramics,siliconnitrideisanimportantnonoxideceramic.,.,accordingtotheiratomicstructualfeature,therearethreetypesofceramicsascrystallineceramics,noncrystallineceramicsandthethirdcategory,glass-ceramics.Siliconnitrideisoneofcrystallineceramics,glassisakindofnoncrystallineceramicsandglass-ceramicsisarelativelyrecentmaterial,thatis,certainglasscompositions(suchaslithiumaluminosilicates)canbefullydevitifiedbyanappropriatethermaltreatment.,.,Polymersarelong-chainmoleculescomposedofmanymersbondtogether.Polyethylene,acrylicsandnylonarealltypicalpolymers.Polymersarenobrittleness,highstrengthalongitschainandlowstrengthbetweenitschains,lightweight,low-cost,lowermeltingpointandhigherchemicalreactivitycomparedwithceramics,atlastpolymersareman-madematerials.,.,shell,.,wood,.,.,.,DComposite(fiberreinforceplastics),PossessinghereditaryhI5redItErIrankinapoliticalsystemorsocialclassderivedfromafeudalistic9fjU:dElIstIkstageofacountrysdevelopment.Inactiveorinert.,1.AlbeitC:l5bi:Itpage12,line5,Eventhough;although;notwithstanding.,2.Noblepage12,para.2,line2,.,Combinationofindividualmaterialsfromthepreviouscategories.Characteristics:thebestofbothworldsItcarryalongthesuperiorpropertiesofeachcomponent,producingaproductthatissuperiortoeitherofthecomponentsseparately.,.,Example:fiberglass,wood,concrete.,.,.,s,.,SupplementaryintroductionSemiconductors,Apieceofequipmentthatproducesapowerfulnarrowbeamoflightthatcanbeusedinmedicaloperations,tocutmetals,ortomakepatternsoflightforentertainment.,1.arsenide5B:sEnaid砷化物,Acompoundofarsenicwithamoreelectropositiveelement.,2.laser,.,Sophisticatedpage13，line6frombelowsE5fistikeitidadj.1.诡辩的,久经世故的2.Verycomplexorcomplicated:非常复杂精密或尖端的最新最尖端的技术thelatestandmostsophisticatedtechnology.,.,Semiconductorsarerelativelyinvisiblecomparedwithpolymers,buthaveacomparablesocialimpact.Semiconductorsarethebasisofmodernelectronics.,.,.,Arelativelysmallgroupofelementsandcompoundshasanimportantelectricalproperty。threesemiconductingelements(Si(silicon),Ge(germaniumdVE:5meiniEm),Sn(tin).compounds:GaAsgallium5AliEmarsenide,CdScadmiumsulfide5kAdmiEm5sQlfaidceramicscompound:ZnOPrecisecontrolofchemicalpurityallowsprecisecontrolofelectronicproperties.,.,Characteristics:semiconduction,inwhichtheyareneithergoodelectricalconductorsnorgoodelectricalinsulators5insjuleitE,instead,theirabilitytoconductelectricityisintermediate7intE5mi:djEt.,.,Atomic-scale-architectureCompositeDevitrifieddi:5vitrifai使不透明DuctilityElectronicandmagneticmaterialFiberglassMaterialsselectionMicrocircuitry5maIkrEJs:kIt电子微电路Microscopic-scalearchitectureRefractoryStructuralmaterial,.,Qustions,1、Pleasedefinecomposites,andthendemonstratethecharacteristicsofgoodcompositesbysomeexamples.2、pleaseenumerate(i5nju:mEreitv.列举)semiconductingelementsandcompounds.,.,Compositeismaterialcomposedofamicroscopic-scalecombinationofindividualmaterialsfromthecategoriesofmetals,ceramics(andglasses),andpolymer.E.g.fiberglassisakindofcompositesystemcomposedofpolymericmatrixreinforcedwithglassfibers.Characteristicoffiberglassprovidesthebestofbothworlds:Itcarryalongthesuperiorpropertiesofeachcomponent,producingaproductthatissuperiortoeitherofthecomponentsseparately.Thehighstrengthofthesmall-diameterglassfibersiscombinedwiththeductilityofthepolymermatrixtoproduceastrongmaterialcapableofwithstandingthenormalloadingrequiredofastructuralmaterial.,.,Therearethreesemiconductingelements(Si,GeandSn)fromcolumnIVAandaclusterofelementsoftheperiodictableimmediatelyadjacenttocolumnIVA,whichformscompoundsthataresemiconducting.Examplesincludegalliumarsenide(GaAs),whichisusedasahigh-temperaturerectifier(5rektifaiE整流器)andalasermaterial,andcadmiumsulfide(CdS)whichisusedasarelativelylow-costsolarcellforconversionofsolarenergytousefulelectricalenergy.,.,1.2Fromstructuretoproperties,TheunitofluminousfluxflQks流量,通量intheInternationalSystem,equaltotheamountoflightgivenoutthroughasolidanglebyasourceofonecandelakAn5di:lEintensityradiatingequallyinalldirections.,1.hexagonalheksAEnEl,Havingsixsides.,2.lumen5lju:min,缩写lm物理学流明（光通量单位）：国际度量系统中的光通量单位，等于一烛光的均匀点光源在单位主体角内发出的光通量.,.,Equivalenti5kwivElEntadj.相等的,相当的,同意义的等价物,相等物Avenue5Avinju:n.林荫道,大街,方法,途径,路Refractionri5frAkFEnn.折光,折射Determinationoftherefractivecharacteristicsoftheeye.屈光度测定：对眼睛折射特性的测定,.,TranslucenttrAnz5lju:sntadj.半透明的,透明的OpaqueEu5peikn.不透明物adj.不透明的,不传热的,迟钝的TransparenttrAns5pZErEntadj.透明的,显然的,明晰的Densification7densifi5keiFEn致密化,.,Tounderstandthepropertiesofengineeringmaterialsitisnecessarytounderstandtheirstructure.,.,Atomic-scalearchitecture10000000times,Microscopic-scalearchitecture1000times,.,Example1:Al,MgAlalloysareductileMgalloysarebrittle,.,AlstructurefollowsacubicpackingarrangementandMgahexagonalone.,.,.,.,Example2:transparentceramicsTraditionalceramicscontainedasubstantialamountofresidualporosity.Theporosityleadstolossofvisiblelighttransmission.Onlyabout0.3%porositycancauseAl2O3tobetranslucent,and3%porositycancausethematerialtobecompletelyopaque.Theeliminationofporosity:,addingasmallamountofimpurity.,.,Theeliminationofporosityresultedfromarelativelysimpleinventionthatinvolvedaddingasmallamountofimpurity(0.1wt%MgO),whichcausedthehigh-temperaturedensificationprocessfortheAl2O3powdertogotocompletion.,.,PorosmicrostructureinpolycrystallineAl2O3,.,Figure1polycrystallinefacetedsapphiresandrubies,Figure3polisheddiscswithseveraldopants(thickness:0.8mm),.,.,Thetwoexamplesjustcitedshowtypicalandimportantdemonstrationsofhowpropertiesofengineeringmaterialsfollowdirectlyfromstructure.,.,Qustions,1.Aluminumandmagnesiumarebothmetal,whyaluminumisrelativelyductilewhilemagnesiumisrelativelybrittle?Pleaseexplainthedramaticeffectthatstructurehasonpropertiesontheatomicscale.2.whytraditionalceramicssuchasaluminumoxideareopaquewhereasrecentlyopticallytransparentaluminumoxideceramicsareproduced?Whatarethedifferencesbetweentheirmicroscopic-scalearchitectures?,.,1.3Selectionofmaterials,anyofagroupofverystronglightweight,syntheticfibersusedinmakingradialtires,bulletproofofvests,etc.,1.etc.,Latinthewrittenabbreviationforetcetera,usedafteralisttoshowthattherearemanyothersimilarthingsorpeoplethatyoucouldhaveadded.andsoforth,andsoon,andtheothers,2.ASTM,AmericanSocietyforTestingandMaterials.,3.aramid,.,Apolymercontainingrepeatedamidegroups,asinvariouskindsofnylon.,4.Aromatic7ArEu5mAtik,Of,relatingto,orcontainingoneormoresix-carbonringscharacteristicofthebenzene5benzi:n,ben5zi:nseriesandrelatedorganicgroups.,5.Polyamide,.,AppreciationE7pri:Fi5eiFEnn.Ajudgmentoropinion,especiallyafavorableone。评价：判断或意见，尤指有益的。2.Materialsselectionisthefinal,practicaldecisionintheengineeringdesignprocessandcandeterminethatdesignsultimatesuccessorfailure.3.solid-stateadj.使用电晶体的,不用真空管的4.indefinitein5definitadj.不确定的,语不定的(indefinitearticle),.,5.althoughsomestructuralceramicscanwithstandtheanticipatedserviceload,serviceload负载6.criterionkrai5tiEriEnn.(批评判断的)标准,准据,规范critical5kritikEladj.评论的,鉴定的,批评的,危急的,临界的,.,7.Theaddedcostoffabricatingthesemoresophisticatedmaterialsystemsisjustifiedonlyifaspecialadvanta