材料科学概论PPT学习教案

1、会计学1材料科学概论材料科学概论第1页/共102页材料与新技术革命材料与新技术革命第2页/共102页第3页/共102页第4页/共102页第5页/共102页第6页/共102页材料与国防现代化材料与国防现代化第7页/共102页sciencematerialsengineering第8页/共102页 Microscopic or submicroscopic structure Engineering design第9页/共102页第10页/共102页nFiberglass 5faIbElB:s第11页/共102页第12页/共102页第13页/共102页What materials are avai

2、lable to me ?Five categories第14页/共102页第15页/共102页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.第16页/共102页Structural steel 第17页/共102页Gasket5Askit垫圈,衬垫springwireValvevAlv第18页/共102页第19页/共102页第20页/共102页第21页/共102

3、页B Ceramics si5rAmiksAhomogeneousmixtureoftwoormoresubstances,whichmaybesolids,liquids,gases,oracombinationofthese.1 . Refractory ri5frAktEriDifficulttomeltorwork;resistanttoheat.2 . fracture toughness断裂韧度3 . crystalline5kristElainBeing,relatingto,orcomposedofcrystalorcrystals.4 . Devitrify di:5vitr

4、ifaiTocause(aglassymaterial)tobecomecrystallineandbrittle.5 . solution第22页/共102页第23页/共102页RubySapphire5sAfaiE第24页/共102页 Why shouldnt Al2O3 be chosen for certain applications where metallic aluminum has been used ?1、Al2O3 have two advantages:first ,chemicallystable;Aloxidizedsecond ,highermeltingpoin

5、t(20200C)Al(6600C)refractoryuseinindustrialfurnaceconstruction第25页/共102页第26页/共102页ThemostlimitingpropertyofceramicsbrittlenessRecentdevelopmentinceramictechnologyareexpandingtheutilityofceramicsforstructuralapplicationnotbyeliminatingtheirinherentbrittleness,butbyincreasingtheirstrengthtosufficientl

6、yhighlevels(greaterthan700MPa)andincreasingtheirresistancetofracture.第27页/共102页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 ceramics第28页/共102页3

7、、Onemetallicelementplusoneoffivenonmetallicelements(C,N,O,P,orS)第29页/共102页4、Characteristics:refractoryhighhardnesshighstrengthhighbrittleness第30页/共102页第31页/共102页第32页/共102页skI5mAtIk第33页/共102页SiO2 (approximately 72%) Na2O CaO brittleness similar with crystalline ceramictransmit visible lightchemical i

8、nertness glasses are important engineering materials第34页/共102页low-thermal expansion coefficientscomplex formshigh mechanical strengthVitreous 5vItrIEsglassy stateSubsequentcrystallization第35页/共102页第36页/共102页第37页/共102页C Polymers(plastics)Exempli gratia. For example.1 . ethylene A colorless, flammable

9、 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, or in the form of fil

10、ms and sheets for packaging.3 . e.g.第38页/共102页 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 contain the recurri

11、ng amide group CONH.6 . Hydrocarbon第39页/共102页 These man-made materials are a branch of organic chemistry .第40页/共102页第41页/共102页第42页/共102页CH2CH2nCH2CH2nnCH2CH2CCH3CH3CH3第43页/共102页 1) no brittleness2. Characteristics: 2) lower melting point3) high strength along its chain and low strength between its c

12、hains 4) lightweight low-cost5) higher chemical reactivity6) Man-made materials第44页/共102页Substitution for traditional structural metals第45页/共102页第46页/共102页第47页/共102页SiO2 (approximately 72%) Na2O CaO brittleness similar with crystalline ceramictransmit visible lightchemical inertness glasses are impo

13、rtant engineering materials第48页/共102页第49页/共102页第50页/共102页第51页/共102页shell第52页/共102页wood第53页/共102页第54页/共102页第55页/共102页D Composite (fiber reinforce plastics) Possessing hereditaryhI5redItErI rank in a political system or social class derived from a feudalistic 9fjU:dElIstIk stage of a countrys developm

14、ent. 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第56页/共102页第57页/共102页Example: fiberglass ,wood ,concrete .第58页/共102页第59页/共102页第60页/共102页 Supplementary introduction Semiconductors A piece of equipment

15、 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第61页/共102页第62页/共102页第63页/共102页第64页/共102页A relatively sma

16、ll group 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 p

17、recise control of electronic properties. 第65页/共102页第66页/共102页Atomic-scale-architectureCompositeDevitrifieddi:5vitrifai 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第67页/共

18、102页第68页/共102页第69页/共102页第70页/共102页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:lE intensity radiating equally in all directions. 1 .hexagonal heksAEnE

19、lHavingsixsides.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.第71页/共102页第72页/共102页第73页/共102页第74页/共102页Atomic-scale architecture10000000 timesMicroscopic-scale architecture1000times第75页/共102页第76页/共102页 Al structure follows a cubic packing arrangement and Mg a hexagonal one

20、 .第77页/共102页第78页/共102页第79页/共102页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

21、 completely opaque .The elimination of porosity : adding a small amount of impurity .第80页/共102页第81页/共102页第82页/共102页Figure3polisheddiscswithseveraldopants(thickness:0.8mm)第83页/共102页第84页/共102页The two examples just cited show typical and important demonstrations of how properties of engineering materials follow directly from structure.第85页/共102页第86页/共102页1.3 Selection of materials anyofagroupofverys