《材料科学概论》PPT课件.ppt

《《材料科学概论》PPT课件.ppt》由会员分享，可在线阅读，更多相关《《材料科学概论》PPT课件.ppt（102页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、Introduction to Materials Science and EngineeringGuan Rui-fang材料与新技术革命材料与新技术革命材料与国防现代化材料与国防现代化This book is divided into four major sectionsI.The fundamentalsII.The structural materialsIII.The electronic and magnetic materialsIV.Materials in engineering designsciencematerialsengineeringNature of mate

2、rials propertiesMicroscopic or submicroscopic structureEngineering designChapter I Materials for Engineering1.1 Types of materials1.2 From structure to properties1.3 Selection of materials1.4 Materials science and engineering Key wordAlloy 5AlCi5AlCi Atomic-scale-architectureBrittle 5britl5britlCera

3、mic si5rAmiksi5rAmikComposite 5kCmpEzit,-zait5kCmpEzit,-zaitConcrete 5kCnkri:t5kCnkri:tConductorCrystalline 5kristElain5kristElain adj.Devitrified di:5vitrifaidi:5vitrifaiDuctility dQk5tilitidQk5tilitiElectronic and magnetic materialElement 5elimEnt5elimEntFiberglass 5faIbElB:s5faIbElB:sGlassGlass-c

4、eramicInsulatorMaterials science and engineeringMaterials selectionMetallicMicrocircuitry 5maIkrEJs:kIt5maIkrEJs:kItMicroscopic-scale architectureNoncrystallineNonmetallic 5nCnmi5tAlik5nCnmi5tAlikKey wordOxidePeriodicpiEri5CdikpiEri5Cdik tablePlasticPolyethylene 7pCli5eWili:n7pCli5eWili:nPolymerProp

5、ertyRefractorySemiconductorSilica硅石，硅石，SiO2Silicate硅酸盐硅酸盐Silicon硅元素硅元素SteelStructural materialwoodKey word1.1 Types of materials a.Metals metallic bond b.Ceramics(glass)ionic aI5RnIkaI5RnIk and covalent kEu5veilEntkEu5veilEnt bond c.Polymers covalent and Van der waals bond d.Composites e.semiconduct

6、orsWhat materials are available to me?Five categoriesA Metals超塑性的,超塑性材料(制)的1.i.e.Latin，the written abbreviation for id est,也就是，即。读作：that is2.state-of-the-art技术发展水平，现代化的。3.superplastic.Characteristics(metallic 金属的，金属性的金属的，金属性的)It is strong and can be readily formed into practical shapes.Ductile 5dQkt

7、ail5dQktail permanent deformabilitymetallic lusterelectric conductor Metals have no brittleness and are safe for many applications.Structural steel Gasket5Askit垫圈,衬垫springwireValvevAlvB Ceramics si5rAmiksAhomogeneousmixtureoftwoormoresubstances,whichmaybesolids,liquids,gases,oracombinationofthese.1.

8、Refractory ri5frAktEriDifficulttomeltorwork;resistanttoheat.2.fracture toughness断裂韧度3.crystalline5kristElainBeing,relatingto,orcomposedofcrystalorcrystals.4.Devitrify di:5vitrifaiTocause(aglassymaterial)tobecomecrystallineandbrittle.5.solutionThe ceramics is derived from Greek word “keramic”which me

9、ans an art of potter.Include :glass ;enamels i5nAmEli5nAmEl;refractories;cements;limes;plasters(plaster of Paris);cermets5sE:met5sE:met金属陶瓷金属陶瓷,含陶合金含陶合金;electronic ceramics;high and low tension electrical insulators;structural clay products;nuclear ceramics;whitewares;abrasives E5breisivE5breisiv.Th

10、e Different Colors of Corundum kE5rQndEmkE5rQndEmkE5rQndEmkE5rQndEm RubySapphire5sAfaiE5sAfaiE Why shouldnt Al2O3 be chosen for certain applications where metallic aluminum has been used?1、Al2O3 have two advantages:first,chemicallystable;Aloxidizedsecond,highermeltingpoint(20200C)Al(6600C)refractory

11、useinindustrialfurnaceconstructionQuestions1.What materials are available to you in this book?2.What fundamental characteristics metals have?3.Please shade metallic elements in periodic table and give some examples of alloys.4.Please list two principal advantages of Al2O3 relative to metallic Al.5.W

12、hats the most limiting property of ceramics.ThemostlimitingpropertyofceramicsbrittlenessRecentdevelopmentinceramictechnologyareexpandingtheutilityofceramicsforstructuralapplicationnotbyeliminatingtheirinherentbrittleness,butbyincreasingtheirstrengthtosufficientlyhighlevels(greaterthan700MPa)andincre

13、asingtheirresistancetofracture.2、Al2O3MgOSiO2Si3N4At least one metallic element+one of five nonmetal element(C,N,O,P and S)Carbide 5kB:baidNitride 5naitraidOxide 5CksaidPhosphide 5fCsfaidSulphide.5sQlfaidOxide ceramicsNonoxide ceramics3、Onemetallicelementplusoneoffivenonmetallicelements(C,N,O,P,orS)

14、4、Characteristics:refractoryhighhardnesshighstrengthhighbrittlenessThe similar structural feature of metals and ceramics:Crystalline:their constituent atoms are stacked together in a regular,repeating pattern.The distinction:ceramics can be made in a noncrystalline form.skI5mAtIkSiO2(approximately 7

15、2%)Na2O CaOGlass:brittleness similar with crystalline ceramictransmit visible lightchemical inertness glasses are important engineering materialsGlass-ceramics is a third categoryLithium aluminosilicatesCertain glass compositions can be fully devitified by an appropriate thermal treatmentlow-thermal

16、 expansion coefficientscomplex formshigh mechanical strengthVitreous 5vItrIEsglassy stateSubsequentcrystallizationC Polymers(plastics)Exempli gratia.For example.1.ethylene A colorless,flammable gas,C2H4,derived from natural gas and petroleum and used as a source of many organic compounds,in welding

17、5weldiN焊接and cutting metals,and as an anesthetic 7Anis5Wetik麻醉剂.2.polyethylene A polymerized ethylene resin,used especially for containers,kitchenware,and tubing,or in the form of films and sheets for packaging.3.e.g.Any of numerous organic compounds,such as benzene and methane,that contain only car

18、bon and hydrogen.4.Acrylics E5kriliks丙烯酸树脂5.Nylon 5nailEn Any of a family of high-strength,resilient synthetic polymers,the molecules of which contain the recurring amide group CONH.6.Hydrocarbon These man-made materials are a branch of organic chemistry.1.Poly+mer:mer in a polymer 1.Poly+mer:mer in

19、 a polymer is a single hydrocarbon molecule is a single hydrocarbon molecule such as ethylene(Csuch as ethylene(C2 2H H4 4).).long chain olecules:long chain olecules:Polymers are long-chain Polymers are long-chain molecules composed of many molecules composed of many mers bond together.mers bond tog

20、ether.1)no brittleness2.Characteristics:2)lower melting point3)high strength along its chain and low strength between its chains 4)lightweight low-cost5)higher chemical reactivity6)Man-made materialsSubstitution for traditional structural metalsQustions1.please illustrate two type of elements that c

21、omposed ceramic compounds in periodic table.2.What are the major compositions of glass?why glasses are important engineering materials?3.Please list two categories and give some examples of ceramics according their compositions.4.Please list three categories and give some examples of ceramics accord

22、ing their atomic structrual feature.5.What are polymers?What are characteristics of polymers?Please give some examples of polymers.SiO2(approximately 72%)Na2O CaOGlass:brittleness similar with crystalline ceramictransmit visible lightchemical inertness glasses are important engineering materialsAcco

23、rding to their compositions,ceramics can be divided into two catogories.One is oxide ceramics such as aluminum oxide(Al2O3),magnesium oxide(MgO),and silica(SiO2),the other one is nonoxide ceramics,silicon nitride is an important nonoxide ceramic.according to their atomic structual feature,there are

24、three types of ceramics as crystalline ceramics,noncrystalline ceramics and the third category,glass-ceramics.Silicon nitride is one of crystalline ceramics,glass is a kind of noncrystalline ceramics and glass-ceramics is a relatively recent material,that is,certain glass compositions(such as lithiu

25、m aluminosilicates)can be fully devitified by an appropriate thermal treatment.Polymers are long-chain molecules Polymers are long-chain molecules composed of many mers bond composed of many mers bond together.together.Polyethylene,acrylics and nylon are Polyethylene,acrylics and nylon are all typic

26、al polymers.all typical polymers.Polymers are no brittleness,high Polymers are no brittleness,high strength along its chain and low strength along its chain and low strength between its chains,strength between its chains,lightweight,low-cost,lower melting lightweight,low-cost,lower melting point and

27、 higher chemical reactivity point and higher chemical reactivity compared with ceramics,at last compared with ceramics,at last polymers are man-made materials.polymers are man-made materials.shellwoodD Composite(fiber reinforce plastics)Possessing hereditaryhI5redItErI rank in a political system or

28、social class derived from a feudalistic 9fjU:dElIstIk stage of a countrys development.Inactive or inert.1.Albeit C:l5bi:It page 12,line 5Even though;although;notwithstanding.2.Noble page 12,para.2,line 2Combination of individual materials from the previous categories.Characteristics:the best of both

29、 worlds It carry along the superior properties of each component,producing a product that is superior to either of the components separately.Example:fiberglass,wood,concrete.s Supplementary introduction Semiconductors A piece of equipment that produces a powerful narrow beam of light that can be use

30、d in medical operations,to cut metals,or to make patterns of light for entertainment.1.arsenide 5B:sEnaid砷化物 A compound of arsenic with a more electropositive element.2.laserSophisticated page 13，line 6 from below sE5fistikeitid adj.1.诡辩的,久经世故的2.Very complex or complicated:非常复杂精密或尖端的最新最尖端的技术 the lat

31、est and most sophisticated technology.Semiconductors are relatively invisible compared with polymers,but have a comparable social impact.Semiconductors are the basis of modern electronics.A relatively small group of elements and compounds has an important electrical property。three semiconducting ele

32、ments (Si(silicon),Ge(germanium dVE:5meiniEmdVE:5meiniEm),Sn(tin).compounds:GaAs gallium5AliEm5AliEm arsenide,CdS cadmiumsulfide 5kAdmiEm5kAdmiEm 5sQlfaid5sQlfaid ceramics compound:ZnO Precise control of chemical purity allows precise control of electronic properties.Characteristics:semiconduction,i

33、n which they are neither good electrical conductors nor good electrical insulators 5insjuleitE5insjuleitE,instead,their ability to conduct electricity is intermediate 7intE5mi:djEt7intE5mi:djEt.Atomic-scale-architectureCompositeDevitrifieddi:5vitrifaidi:5vitrifai 使不透明使不透明DuctilityElectronic and magn

34、etic materialFiberglassMaterials selectionMicrocircuitry 5maIkrEJs:kIt5maIkrEJs:kIt电子电子微电路微电路Microscopic-scale architectureRefractoryStructural materialQustions1、Please define composites,and then demonstrate the characteristics of good composites by some examples.2、please enumerate(i5nju:mEreit v.列举

35、)semiconducting elements and compounds.Compositeismaterialcomposedofamicroscopic-scalecombinationofindividualmaterialsfromthecategoriesofmetals,ceramics(andglasses),andpolymer.E.g.fiberglassisakindofcompositesystemcomposedofpolymericmatrixreinforcedwithglassfibers.Characteristicoffiberglassprovidest

36、hebestofbothworlds:Itcarryalongthesuperiorpropertiesofeachcomponent,producingaproductthatissuperiortoeitherofthecomponentsseparately.Thehighstrengthofthesmall-diameterglassfibersiscombinedwiththeductilityofthepolymermatrixtoproduceastrongmaterialcapableofwithstandingthenormalloadingrequiredofastruct

37、uralmaterial.Therearethreesemiconductingelements(Si,GeandSn)fromcolumnIVAandaclusterofelementsoftheperiodictableimmediatelyadjacenttocolumnIVA,whichformscompoundsthataresemiconducting.Examplesincludegalliumarsenide(GaAs),whichisusedasahigh-temperaturerectifier(5rektifaiE整流器)andalasermaterial,andcadm

38、iumsulfide(CdS)whichisusedasarelativelylow-costsolarcellforconversionofsolarenergytousefulelectricalenergy.1.2 From structure to properties The unit of luminous flux flQks流量,通量 in the International System,equal to the amount of light given out through a solid angle by a source of one candela kAn5di:

39、lE intensity radiating equally in all directions.1.hexagonal heksAEnElHavingsixsides.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.Equivalent i5kwivElEnt adj.相等的,相当的,同意义的n.等价物,相等物Avenue 5Avinju:n.林荫道,大街,方法,途径,路Refraction ri5frAkFEnn.折光,折射Determination of the refractive cha

40、racteristics of the eye.屈光度测定：对眼睛折射特性的测定Translucent trAnz5lju:sntadj.半透明的,透明的Opaque Eu5peikn.不透明物adj.不透明的,不传热的,迟钝的Transparent trAns5pZErEntadj.透明的,显然的,明晰的Densification 7densifi5keiFEn致密化 To understand the properties of engineering materials it is necessary to understand their structure.Atomic-scale

41、architecture10000000 timesMicroscopic-scale architecture1000timesExample 1:Al,Mg Al alloys are ductile Mg alloys are brittle Al structure follows a cubic packing arrangement and Mg a hexagonal one.Example 2:transparent ceramicsTraditional ceramics contained a substantial amount of residual porosity.

42、The porosity leads to loss of visible light transmission.Only about 0.3%porosity can cause Al2O3 to be translucent,and 3%porosity can cause the material to be completely opaque.The elimination of porosity:adding a small amount of impurity.Theeliminationofporosityresultedfromarelativelysimpleinventio

43、nthatinvolvedaddingasmallamountofimpurity(0.1wt%MgO),whichcausedthehigh-temperaturedensificationprocessfortheAl2O3powdertogotocompletion.Poros microstructure in polycrystalline Al2O3Figure 1polycrystalline faceted sapphires and rubiesFigure3polisheddiscswithseveraldopants(thickness:0.8mm)The two exa

44、mples just cited show typical and important demonstrations of how properties of engineering materials follow directly from structure.Qustions1.Aluminumandmagnesiumarebothmetal,whyaluminumisrelativelyductilewhilemagnesiumisrelativelybrittle?Pleaseexplainthedramaticeffectthatstructurehasonpropertieson

45、theatomicscale.2.whytraditionalceramicssuchasaluminumoxideareopaquewhereasrecentlyopticallytransparentaluminumoxideceramicsareproduced?Whatarethedifferencesbetweentheirmicroscopic-scalearchitectures?1.3 Selection of materials anyofagroupofverystronglightweight,syntheticfibersusedinmakingradialtires,

46、bulletproofofvests,etc.1.etc.Latinthewrittenabbreviationforetcetera,usedafteralisttoshowthattherearemanyothersimilarthingsorpeoplethatyoucouldhaveadded.andsoforth,andsoon,andtheothers2.ASTMAmericanSocietyforTestingandMaterials.3.aramid Apolymercontainingrepeatedamidegroups,asinvariouskindsofnylon.4.

47、Aromatic 7ArEu5mAtikOf,relatingto,orcontainingoneormoresix-carbonringscharacteristicofthebenzene5benzi:n,ben5zi:nseriesandrelatedorganicgroups.5.PolyamideAppreciationE7pri:Fi5eiFEnn.Ajudgmentoropinion,especiallyafavorableone。评价：判断或意见，尤指有益的。2.Materialsselectionisthefinal,practicaldecisionintheenginee

48、ringdesignprocessandcandeterminethatdesignsultimatesuccessorfailure.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,

49、鉴定的,批评的,危急的,临界的7.Theaddedcostoffabricatingthesemoresophisticatedmaterialsystemsisjustifiedonlyifaspecialadvantageresults.fabricate5fAbrikeitvt.制作,构成,捏造,伪造,虚构JustifyTodemonstrateorprovetobejust,right,orvalid:论证或证明正当、正确或有效8.optimal5CptimEladj.最佳的,最理想的9.propertycomparisonkEm5pArisn10.junction5dVQNkFEnn

50、.连接,接合,交叉点,汇合处10.spherical5sferikEladj.球的,球形的;cylindricalsI5lIndrIk(E)l圆柱的11.integral5intirEladj.Essentialornecessaryforcompleteness;constituent:必须的：构成整体所必须的；应有的12.Inthepastquartercentury,thetermthathascometolabelthegeneralbranchofengineeringconcernedwithmaterialsismaterials science and engineering.