材料科学概论ppt课件

1、整理课件整理课件整理课件材料与新技术革命材料与新技术革命整理课件整理课件整理课件整理课件整理课件材料与国防现代化材料与国防现代化整理课件This book is divided into four major sectionsThe fundamentalsThe structural materialsThe electronic and magnetic materialsMaterials in engineering designsciencematerialsengineering整理课件 Nature of materials properties Microscopic or s

2、ubmicroscopic structure Engineering design整理课件1.1 Types of materials1.2 From structure to properties1.3 Selection of materials1.4 Materials science and engineering 整理课件 Alloy 5AlCi Atomic-scale-architecture Brittle 5britl Ceramic si5rAmik Composite 5kCmpEzit, -zait Concrete 5kCnkri:t Conductor Cryst

3、alline 5kristElain adj. Devitrified di:5vitrifai Ductility dQk5tiliti Electronic and magnetic material Element 5elimEnt Fiberglass 5faIbElB:s整理课件 Glass Glass-ceramic Insulator Materials science and engineering Materials selection Metallic Microcircuitry 5maIkrEJs:kIt Microscopic-scale architecture N

4、oncrystalline Nonmetallic 5nCnmi5tAlik整理课件 Oxide PeriodicpiEri5Cdik table Plastic Polyethylene 7pCli5eWili:n Polymer Property Refractory Semiconductor Silica硅石，硅石，SiO2 Silicate硅酸盐硅酸盐 Silicon硅元素硅元素 Steel Structural material wood整理课件 a . Metals metallic bond b . Ceramics (glass) ionic aI5RnIk and cova

5、lent kEu5veilEnt bond c . Polymers covalent and Van der waals bond d . Composites e . semiconductorsWhat materials are available to me ?Five categories整理课件整理课件A 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.整

6、理课件 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 5dQktail permanent deformability metallic luster electric conductor Metals have no brittleness and are safe for many applications.Structural steel 整理课件Gasket5Askit垫圈,衬垫springwireValv

7、evAlv整理课件整理课件整理课件B Ceramics si5rAmiksAhomogeneousmixtureoftwoormoresubstances,whichmaybesolids,liquids,gases,oracombinationofthese.1 . Refractory ri5frAktEriDifficulttomeltorwork;resistanttoheat.2 . fracture toughness断裂韧度3 . crystalline5kristElainBeing,relatingto,orcomposedofcrystalorcrystals.4 . De

8、vitrify di:5vitrifaiTocause(aglassymaterial)tobecomecrystallineandbrittle.5 . solution整理课件 The ceramics is derived from Greek word “keramic” which means an art of potter .Include : glass ; enamels i5nAmEl ; refractories ; cements ; limes ; plasters(plaster of Paris) ; cermets5sE:met金属陶瓷金属陶瓷, 含陶合金含陶合

9、金; electronic ceramics ; high and low tension electrical insulators ; structural clay products ; nuclear ceramics ; whitewares ; abrasives E5breisiv .整理课件RubySapphire5sAfaiE整理课件 Why shouldnt Al2O3 be chosen for certain applications where metallic aluminum has been used ?1、Al2O3 have two advantages:f

10、irst ,chemicallystable;Aloxidizedsecond ,highermeltingpoint(20200C)Al(6600C)refractoryuseinindustrialfurnaceconstruction整理课件What materials are available to you in this book?What fundamental characteristics metals have?Please shade metallic elements in periodic table and give some examples of alloys.

11、Please list two principal advantages of Al2O3 relative to metallic Al.Whats the most limiting property of ceramics.整理课件ThemostlimitingpropertyofceramicsbrittlenessRecentdevelopmentinceramictechnologyareexpandingtheutilityofceramicsforstructuralapplicationnotbyeliminatingtheirinherentbrittleness,butb

12、yincreasingtheirstrengthtosufficientlyhighlevels(greaterthan700MPa)andincreasingtheirresistancetofracture.整理课件2、Al2O3MgOSiO2Si3N4At least one metallic element +one of five nonmetal element (C, N, O, P and S)Carbide 5kB:baidNitride 5naitraidOxide 5CksaidPhosphide 5fCsfaidSulphide. 5sQlfaidOxide ceram

13、icsNonoxide ceramics整理课件3、Onemetallicelementplusoneoffivenonmetallicelements(C,N,O,P,orS)整理课件4、Characteristics:refractoryhighhardnesshighstrengthhighbrittleness整理课件整理课件整理课件 The similar structural feature of metals and ceramics: Crystalline: their constituent atoms are stacked together in a regular,

14、repeating pattern. The distinction: ceramics can be made in a noncrystalline form . skI5mAtIk整理课件SiO2 (approximately 72%) Na2O CaO brittleness similar with crystalline ceramictransmit visible lightchemical inertness glasses are important engineering materials整理课件Glass-ceramics is a third categoryLit

15、hium aluminosilicatesCertain glass compositions can be fully devitified by an appropriate thermal treatmentlow-thermal expansion coefficientscomplex formshigh mechanical strengthVitreous 5vItrIEsglassy stateSubsequentcrystallization整理课件整理课件C Polymers(plastics)Exempli gratia. For example.1 . ethylene

16、 A colorless, flammable gas, C2H4, derived from natural gas and petroleum and used as a source of many organic compounds, in welding 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

17、, or in the form of films and sheets for packaging.3 . e.g.整理课件 Any of numerous organic compounds, such as benzene and methane, that contain only carbon 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 co

18、ntain the recurring amide group CONH.6 . Hydrocarbon整理课件 These man-made materials are a branch of organic chemistry .整理课件整理课件 1. Poly +mer: mer in a polymer 1. Poly +mer: mer in a polymer is a single hydrocarbon is a single hydrocarbon molecule such as ethylene(Cmolecule such as ethylene(C2 2H H4 4)

19、. ). 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 together.整理课件CH2CH2nCH2CH2nnCH2CH2CCH3CH3CH3整理课件 1) no brittleness2. Characteristics: 2) lower melting point3) high streng

20、th along its chain and low strength between its chains 4) lightweight low-cost5) higher chemical reactivity6) Man-made materials整理课件Substitution for traditional structural metals整理课件please illustrate two type of elements that composed ceramic compounds in periodic table.What are the major compositio

21、ns of glass? why glasses are important engineering materials?Please list two categories and give some examples of ceramics according their compositions.Please list three categories and give some examples of ceramics according their atomic structrual feature.What are polymers? What are characteristic

22、s of polymers? Please give some examples of polymers.整理课件整理课件SiO2 (approximately 72%) Na2O CaO brittleness similar with crystalline ceramictransmit visible lightchemical inertness glasses are important engineering materials整理课件 According to their compositions, ceramics can be divided into two catogo

23、ries. 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. 整理课件 according to their atomic structual feature, there are three types of ceramics as crystalline ceramics, non

24、crystalline 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 lithium aluminosilicates ) can be fully devitified

25、by an appropriate thermal treatment. 整理课件 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 typical polymers.all typical polymers.

26、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 higher chemical reactivi

27、ty 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.整理课件shell整理课件wood整理课件整理课件整理课件D Composite (fiber reinforce plastics) Possessing hereditaryhI5redItErI rank in a political system or s

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

29、. Characteristics: the best of both worlds It carry along the superior properties of each component, producing a product that is superior to either of the components separately.整理课件Example: fiberglass ,wood ,concrete .整理课件整理课件整理课件 Supplementary introduction Semiconductors A piece of equipment that p

30、roduces a powerful narrow beam of light that can be used 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 .laser整理课件 Sophisticated page 13，line 6 from below sE5fistikeitid adj

31、.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 latest and most sophisticated technology.整理课件 Semiconductors are relatively invisible compared with polymers , but have a comparable social impact. Semiconductors are the basis of modern electronics.整理课件整理课件A relatively small group

32、of elements and compounds has an important electrical property。three semiconducting elements (Si (silicon),Ge (germanium dVE:5meiniEm ) , Sn(tin). compounds: GaAs gallium5AliEm arsenide, CdS cadmiumsulfide 5kAdmiEm 5sQlfaid ceramics compound : ZnO Precise control of chemical purity allows precise co

33、ntrol of electronic properties. 整理课件 Characteristics: semiconduction, in which they are neither good electrical conductors nor good electrical insulators 5insjuleitE , instead, their ability to conduct electricity is intermediate 7intE5mi:djEt. 整理课件Atomic-scale-architectureCompositeDevitrifieddi:5vi

34、trifai 使不透明使不透明DuctilityElectronic and magnetic materialFiberglassMaterials selectionMicrocircuitry 5maIkrEJs:kIt电子电子微电路微电路Microscopic-scale architectureRefractoryStructural material整理课件1、Please define composites, and then demonstrate the characteristics of good composites by some examples. 2、please

35、 enumerate ( i5nju:mEreit v.列举) semiconducting elements and compounds.整理课件Compositeismaterialcomposedofamicroscopic-scalecombinationofindividualmaterialsfromthecategoriesofmetals,ceramics(andglasses),andpolymer.E.g.fiberglassisakindofcompositesystemcomposedofpolymericmatrixreinforcedwithglassfibers.

36、Characteristicoffiberglassprovidesthebestofbothworlds:Itcarryalongthesuperiorpropertiesofeachcomponent,producingaproductthatissuperiortoeitherofthecomponentsseparately.Thehighstrengthofthesmall-diameterglassfibersiscombinedwiththeductilityofthepolymermatrixtoproduceastrongmaterialcapableofwithstandi

37、ngthenormalloadingrequiredofastructuralmaterial.整理课件 Therearethreesemiconductingelements(Si,GeandSn)fromcolumnIVAandaclusterofelementsoftheperiodictableimmediatelyadjacenttocolumnIVA,whichformscompoundsthataresemiconducting.Examplesincludegalliumarsenide(GaAs),whichisusedasahigh-temperaturerectifier

38、(5rektifaiE整流器)andalasermaterial,andcadmiumsulfide(CdS)whichisusedasarelativelylow-costsolarcellforconversionofsolarenergytousefulelectricalenergy.整理课件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

39、solid angle by a source of one candela kAn5di: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.整理课件Equivalent i5kwivElEnt adj. 相等的, 相当的, 同意义的等价物, 相等物Avenue 5Avinju: n. 林荫道, 大街, 方法, 途径, 路Re

40、fraction ri5frAkFEnn. 折光, 折射Determination of the refractive characteristics of the eye. 屈光度测定：对眼睛折射特性的测定整理课件 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致密化整理课件 To understand the properties

41、of engineering materials it is necessary to understand their structure .整理课件Atomic-scale architecture10000000 timesMicroscopic-scale architecture1000times整理课件Example 1: Al , Mg Al alloys are ductile Mg alloys are brittle整理课件 Al structure follows a cubic packing arrangement and Mg a hexagonal one .整理

42、课件整理课件整理课件Example 2: transparent ceramicsTraditional ceramics contained a substantial amount of residual porosity .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 .Th

43、e elimination of porosity : adding a small amount of impurity .整理课件 Theeliminationofporosityresultedfromarelativelysimpleinventionthatinvolvedaddingasmallamountofimpurity(0.1wt%MgO),whichcausedthehigh-temperaturedensificationprocessfortheAl2O3powdertogotocompletion.整理课件 Poros microstructure in polyc

44、rystalline Al2O3整理课件Figure 1polycrystalline faceted sapphires and rubiesFigure3polisheddiscswithseveraldopants(thickness:0.8mm)整理课件整理课件The two examples just cited show typical and important demonstrations of how properties of engineering materials follow directly from structure.整理课件 1.Aluminumandmag

45、nesiumarebothmetal,whyaluminumisrelativelyductilewhilemagnesiumisrelativelybrittle?Pleaseexplainthedramaticeffectthatstructurehasonpropertiesontheatomicscale. 2.whytraditionalceramicssuchasaluminumoxideareopaquewhereasrecentlyopticallytransparentaluminumoxideceramicsareproduced?Whatarethedifferences

46、betweentheirmicroscopic-scalearchitectures?整理课件1.3 Selection of materials anyofagroupofverystronglightweight,syntheticfibersusedinmakingradialtires,bulletproofofvests,etc.1 . etc. Latinthewrittenabbreviationforetcetera,usedafteralisttoshowthattherearemanyothersimilarthingsorpeoplethatyoucouldhaveadd

47、ed.andsoforth,andsoon,andtheothers2 . ASTMAmericanSocietyforTestingandMaterials.3 . aramid整理课件 Apolymercontainingrepeatedamidegroups,asinvariouskindsofnylon. 4 . Aromatic 7ArEu5mAtikOf,relatingto,orcontainingoneormoresix-carbonringscharacteristicofthebenzene5benzi:n, ben5zi:nseriesandrelatedorganicgroups.5 . Polyamide整理课件 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.indefin