《材料科学概论》PPT课件.ppt

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1、Introduction to Materials Science and Engineering,Guan Rui-fang,材料与新技术革命,材料与国防现代化,This book is divided into four major sectionsThe fundamentalsThe structural materialsThe electronic and magnetic materialsMaterials in engineering design,Nature of materials properties,Microscopic or submicroscopic str

2、ucture,Engineering design,Chapter I Materials for Engineering,1.1 Types of materials1.2 From structure to properties1.3 Selection of materials1.4 Materials science and engineering,Key word,Alloy 5AlCi Atomic-scale-architectureBrittle 5britlCeramic si5rAmikComposite 5kCmpEzit,-zaitConcrete 5kCnkri:tC

3、onductorCrystalline 5kristElain adj.Devitrified di:5vitrifaiDuctility dQk5tilitiElectronic and magnetic materialElement 5elimEntFiberglass 5faIbElB:s,GlassGlass-ceramicInsulatorMaterials science and engineeringMaterials selectionMetallicMicrocircuitry 5maIkrEJs:kItMicroscopic-scale architectureNoncr

4、ystallineNonmetallic 5nCnmi5tAlik,Key word,OxidePeriodicpiEri5Cdik tablePlasticPolyethylene 7pCli5eWili:nPolymerPropertyRefractorySemiconductorSilica硅石，SiO2Silicate硅酸盐Silicon硅元素Steel,Structural materialwood,Key word,1.1 Types of materials,a.Metals metallic bond b.Ceramics(glass)ionic aI5RnIk and cov

5、alent kEu5veilEnt bond c.Polymers covalent and Van der waals bond d.Composites e.semiconductors,What materials are available to me?,Five categories,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 is,2.state-of-the-art,技术发展水平，现代化的。,3.superplastic.,Characteristic

6、s(metallic 金属的，金属性的)It is strong and can be readily formed into practical shapes.Ductile 5dQktail permanent deformabilitymetallic lusterelectric conductor Metals have no brittleness and are safe for many applications.,Structural steel,Gasket 5Askit垫圈,衬垫,spring,wire,Valve vAlv,B Ceramics si5rAmiks,A

7、homogeneous mixture of two or more substances,which may be solids,liquids,gases,or a combination of these.,1.Refractory ri5frAktEri,Difficult to melt or work;resistant to heat.,2.fracture toughness,断裂韧度,3.crystalline5kristElain,Being,relating to,or composed of crystal or crystals.,4.Devitrify di:5vi

8、trifai,To cause(a glassy material)to become crystalline and brittle.,5.solution,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,含陶合金;electronic ceramics;high and low te

9、nsion electrical insulators;structural clay products;nuclear ceramics;whitewares;abrasives E5breisiv.,The Different Colors of Corundum kE5rQndEm,Ruby,Sapphire5sAfaiE,Why shouldnt Al2O3 be chosen for certain applications where metallic aluminum has been used?,1、Al2O3 have two advantages:,first,chemic

10、ally stable;,Al oxidized,second,higher melting point(20200C),Al(6600C),refractory,use in industrial furnace construction,Questions,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

11、alloys.Please list two principal advantages of Al2O3 relative to metallic Al.Whats the most limiting property of ceramics.,The most limiting property of ceramics,brittleness,Recent development in ceramic technology are expanding the utility of ceramics for structural application not by eliminating t

12、heir inherent brittleness,but by increasing their strength to sufficiently high levels(greater than 700MPa)and increasing their resistance to fracture.,2、Al2O3 MgO SiO2 Si3N4,At least one metallic element+one of five nonmetal element(C,N,O,P and S)Carbide 5kB:baidNitride 5naitraidOxide 5CksaidPhosph

13、ide 5fCsfaidSulphide.5sQlfaid,Oxide ceramics,Nonoxide ceramics,3、One metallic element plus one of five nonmetallic elements(C,N,O,P,or S),4、Characteristics:,refractory,high hardness,high strength,high brittleness,The similar structural feature of metals and ceramics:Crystalline:their constituent ato

14、ms are stacked together in a regular,repeating pattern.The distinction:ceramics can be made in a noncrystalline form.,skI5mAtIk,SiO2(approximately 72%)Na2O CaO,Glass:,brittleness,similar with crystalline ceramic,Glass-ceramics is a third categoryLithium aluminosilicatesCertain glass compositions can

15、 be fully devitified by an appropriate thermal treatment,low-thermal expansion coefficients,complex forms,high mechanical strength,Vitreous 5vItrIEs,glassy state,Subsequentcrystallization,C Polymers(plastics),Exempli gratia.For example.,1.ethylene,A colorless,flammable gas,C2H4,derived from natural

16、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,or in the form of films and sheets for packaging.,3.e.g.,Any

17、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 contain the recurring amide group CONH.,6.Hydrocarbon,These man-made materi

18、als are a branch of organic chemistry.,1.Poly+mer:mer in a polymer is a single hydrocarbon molecule such as ethylene(C2H4).long chain olecules:Polymers are long-chain molecules composed of many mers bond together.,1)no brittleness,2.Characteristics:,2)lower melting point,3)high strength along its ch

19、ain and low strength between its chains,4)lightweight low-cost,5)higher chemical reactivity,6)Man-made materials,Substitution for traditional structural metals,Qustions,please illustrate two type of elements that composed ceramic compounds in periodic table.What are the major compositions of glass?w

20、hy 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 characteristics of polymers?P

21、lease give some examples of polymers.,SiO2(approximately 72%)Na2O CaO,Glass:,brittleness,similar with crystalline ceramic,According 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 on

22、e is nonoxide ceramics,silicon nitride is an important nonoxide ceramic.,according to their atomic structual feature,there are 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

23、of noncrystalline ceramics and glass-ceramics is a relatively recent material,that is,certain glass compositions(such as lithium aluminosilicates)can be fully devitified by an appropriate thermal treatment.,Polymers are long-chain molecules composed of many mers bond together.Polyethylene,acrylics a

24、nd nylon are all typical polymers.Polymers are no brittleness,high strength along its chain and low strength between its chains,lightweight,low-cost,lower melting point and higher chemical reactivity compared with ceramics,at last polymers are man-made materials.,shell,wood,D Composite(fiber reinfor

25、ce plastics),Possessing hereditaryhI5redItErI rank in a political system or social class derived from a feudalistic 9fjU:dElIstIk stage of a countrys development.Inactive or inert.,1.Albeit C:l5bi:It page 12,line 5,Even though;although;notwithstanding.,2.Noble page 12,para.2,line 2,Combination of in

26、dividual materials from the previous categories.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.,Example:fiberglass,wood,concrete.,s,Supplementary introduction Semiconductors,

27、A piece of equipment that produces 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,Sophisticated page 13，line 6 from below s

28、E5fistikeitid 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 latest 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

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

30、electronic properties.,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.,Atomic-scale-architectureCompositeDevitrifieddi:5vitrifai 使不透明DuctilityEle

31、ctronic and magnetic materialFiberglassMaterials selectionMicrocircuitry 5maIkrEJs:kIt电子微电路Microscopic-scale architectureRefractoryStructural material,Qustions,1、Please define composites,and then demonstrate the characteristics of good composites by some examples.2、please enumerate(i5nju:mEreit v.列举

32、)semiconducting elements and compounds.,Composite is material composed of a microscopic-scale combination of individual materials from the categories of metals,ceramics(and glasses),and polymer.E.g.fiberglass is a kind of composite system composed of polymeric matrix reinforced with glass fibers.Cha

33、racteristic of fiberglass provides 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.The high strength of the small-diameter glass fibers is combined with the ductility of the polymer matrix to

34、 produce a strong material capable of withstanding the normal loading required of a structural material.,There are three semiconducting elements(Si,Ge and Sn)from column IVA and a cluster of elements of the periodic table immediately adjacent to column IVA,which forms compounds that are semiconducti

35、ng.Examples include gallium arsenide(GaAs),which is used as a high-temperature rectifier(5rektifaiE 整流器)and a laser material,and cadmium sulfide(CdS)which is used as a relatively low-cost solar cell for conversion of solar energy to useful electrical energy.,1.2 From structure to properties,The unit

36、 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:lE intensity radiating equally in all directions.,1.hexagonal heksAEnEl,Having six sides.,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

37、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 characteristics 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 trAns5pZErEntad

38、j.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 architecture10000000 times,Microscopic-scale architecture1000times,Example 1:Al,Mg Al alloys are ductile Mg alloys are brittle,Al structure

39、follows a cubic packing arrangement and Mg a hexagonal one.,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 cau

40、se the material to be completely opaque.The elimination of porosity:,adding a small amount of impurity.,The elimination of porosity resulted from a relatively simple invention that involved adding a small amount of impurity(0.1 wt%MgO),which caused the high-temperature densification process for the

41、Al2O3 powder to go to completion.,Poros microstructure in polycrystalline Al2O3,Figure 1polycrystalline faceted sapphires and rubies,Figure 3polished discs with several dopants(thickness:0.8 mm),The two examples just cited show typical and important demonstrations of how properties of engineering ma

42、terials follow directly from structure.,Qustions,1.Aluminum and magnesium are both metal,why aluminum is relatively ductile while magnesium is relatively brittle?Please explain the dramatic effect that structure has on properties on the atomic scale.2.why traditional ceramics such as aluminum oxide

43、are opaque whereas recently optically transparent aluminum oxide ceramics are produced?What are the differences between their microscopic-scale architectures?,1.3 Selection of materials,any of a group of very strong light weight,synthetic fibers used in making radial tires,bullet proof of vests,etc.

44、,1.etc.,Latin the written abbreviation for et cetera,used after a list to show that there are many other similar things or people that you could have added.and so forth,and so on,and the others,2.ASTM,American Society for Testing and Materials.,3.aramid,A polymer containing repeated amide groups,as

45、in various kinds of nylon.,4.Aromatic 7ArEu5mAtik,Of,relating to,or containing one or more six-carbon rings characteristic of the benzene 5benzi:n,ben5zi:n series and related organic groups.,5.Polyamide,Appreciation E7pri:Fi5eiFEn n.A judgment or opinion,especially a favorable one。评价：判断或意见，尤指有益的。2.M

46、aterials selection is the final,practical decision in the engineering design process and can determine that designs ultimate success or failure.3.solid-state adj.使用电晶体的,不用真空管的4.indefinite in5definit adj.不确定的,语不定的(indefinite article),5.although some structural ceramics can withstand the anticipated s

47、ervice load,service load负载6.criterion krai5tiEriEn n.(批评判断的)标准,准据,规范critical 5kritikEl adj.评论的,鉴定的,批评的,危急的,临界的,7.The added cost of fabricating these more sophisticated material systems is justified only if a special advantage results.fabricate 5fAbrikeit vt.制作,构成,捏造,伪造,虚构 Justify To demonstrate or p

48、rove to be just,right,or valid:论证或证明正当、正确或有效8.optimal 5CptimEl adj.最佳的,最理想的9.property comparison kEm5pArisn10.junction 5dVQNkFEn n.连接,接合,交叉点,汇合处,10.spherical 5sferikEl adj.球的,球形的;cylindrical sI5lIndrIk(E)l 圆柱的11.integral 5intirEl adj.Essential or necessary for completeness;constituent:必须的：构成整体所必须的；应

49、有的,12.In the past quarter century,the term that has come to label the general branch of engineering concerned with materials is materials science and engineering.This label is accurate in that this field is a true blend of fundamental,scientific studies and practical engineering.It has grown to incl

50、ude contributions from many traditional fields,including metallurgy,ceramic engineering,polymer chemistry,solid-state physics,and physical chemistry.,Label 5leibl vt To identify or designate with a label;describe or classify:把归类，描述：用标签分别或命名；描绘或归类contribution 7kCntri5bju:FEn n.捐献,贡献,投稿metallurgy me5t