材料科学概论

1、Introduction to Materials Science and Engineering,Guan Rui-fang,1,PPT学习交流,2,PPT学习交流,材料与新技术革命,3,PPT学习交流,4,PPT学习交流,5,PPT学习交流,6,PPT学习交流,7,PPT学习交流,材料与国防现代化,8,PPT学习交流,This book is divided into four major sections The fundamentals The structural materials The electronic and magnetic materials Materials in

2、 engineering design,9,PPT学习交流,Nature of materials properties,Microscopic or submicroscopic structure,Engineering design,10,PPT学习交流,Chapter I Materials for Engineering,1.1 Types of materials 1.2 From structure to properties 1.3 Selection of materials 1.4 Materials science and engineering,11,PPT学习交流,K

3、ey word,Alloy 5AlCi Atomic-scale-architecture Brittle 5britl Ceramic si5rAmik Composite 5kCmpEzit, -zait Concrete 5kCnkri:t Conductor Crystalline 5kristElain adj. Devitrified di:5vitrifai Ductility dQk5tiliti Electronic and magnetic material Element 5elimEnt Fiberglass 5faIbElB:s,12,PPT学习交流,Glass Gl

4、ass-ceramic Insulator Materials science and engineering Materials selection Metallic Microcircuitry 5maIkrEJs:kIt Microscopic-scale architecture Noncrystalline Nonmetallic 5nCnmi5tAlik,Key word,13,PPT学习交流,Oxide PeriodicpiEri5Cdik table Plastic Polyethylene 7pCli5eWili:n Polymer Property Refractory S

5、emiconductor Silica硅石，SiO2 Silicate硅酸盐 Silicon硅元素 Steel,Structural material wood,Key word,14,PPT学习交流,1.1 Types of materials,a . Metals metallic bond b . Ceramics (glass) ionic aI5RnIk and covalent kEu5veilEnt bond c . Polymers covalent and Van der waals bond d . Composites e . semiconductors,What ma

6、terials are available to me ?,Five categories,15,PPT学习交流,16,PPT学习交流,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.,17,PPT学习交流,Characteristics(metallic 金属的，金属性的) It is strong and can be readily formed

7、into practical shapes . Ductile 5dQktail permanent deformability metallic luster electric conductor Metals have no brittleness and are safe for many applications.,Structural steel,18,PPT学习交流,Gasket 5Askit 垫圈, 衬垫,spring,wire,Valve vAlv,19,PPT学习交流,20,PPT学习交流,21,PPT学习交流,22,PPT学习交流,B Ceramics si5rAmiks,

8、A 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 .

9、 Devitrify di:5vitrifai,To cause (a glassy material) to become crystalline and brittle.,5 . solution,23,PPT学习交流,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) ; cermets5s

10、E:met金属陶瓷, 含陶合金; electronic ceramics ; high and low tension electrical insulators ; structural clay products ; nuclear ceramics ; whitewares ; abrasives E5breisiv .,24,PPT学习交流,The Different Colors of Corundum kE5rQndEm,Ruby,Sapphire 5sAfaiE,25,PPT学习交流,Why shouldnt Al2O3 be chosen for certain applica

11、tions where metallic aluminum has been used ?,1、Al2O3 have two advantages:,first ,chemically stable ;,Al oxidized,second ,higher melting point (20200C),Al (6600C),refractory,use in industrial furnace construction,26,PPT学习交流,Questions,What materials are available to you in this book? What fundamental

12、 characteristics metals have? Please shade metallic elements in periodic table and give some examples of alloys. Please list two principal advantages of Al2O3 relative to metallic Al. Whats the most limiting property of ceramics.,27,PPT学习交流,The most limiting property of ceramics,brittleness,Recent d

13、evelopment in ceramic technology are expanding the utility of ceramics for structural application not by eliminating their inherent brittleness, but by increasing their strength to sufficiently high levels (greater than 700MPa) and increasing their resistance to fracture.,28,PPT学习交流,2、Al2O3 MgO SiO2

14、 Si3N4,At least one metallic element +one of five nonmetal element (C, N, O, P and S) Carbide 5kB:baid Nitride 5naitraid Oxide 5Cksaid Phosphide 5fCsfaid Sulphide. 5sQlfaid,Oxide ceramics,Nonoxide ceramics,29,PPT学习交流,3、One metallic element plus one of five nonmetallic elements (C, N, O, P, or S),30,

15、PPT学习交流,4、Characteristics:,refractory,high hardness,high strength,high brittleness,31,PPT学习交流,32,PPT学习交流,33,PPT学习交流,The 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

16、in a noncrystalline form .,skI5mAtIk,34,PPT学习交流,SiO2 (approximately 72%) Na2O CaO,Glass:,brittleness,similar with crystalline ceramic,35,PPT学习交流,Glass-ceramics is a third category Lithium aluminosilicates Certain glass compositions can be fully devitified by an appropriate thermal treatment,low-ther

17、mal expansion coefficients,complex forms,high mechanical strength,Vitreous 5vItrIEs,glassy state,Subsequent crystallization,36,PPT学习交流,37,PPT学习交流,38,PPT学习交流,C Polymers(plastics),Exempli gratia. For example.,1 . ethylene,A colorless, flammable gas, C2H4, derived from natural gas and petroleum and use

18、d 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.,39,PPT学习交流,Any of n

19、umerous 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,40,PPT学习交流,Thes

20、e man-made materials are a branch of organic chemistry .,41,PPT学习交流,42,PPT学习交流,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.,43,PPT学习交流,44,PPT学习交流,1) no brittleness,2

21、. Characteristics:,2) lower melting point,3) high strength along its chain and low strength between its chains,4) lightweight low-cost,5) higher chemical reactivity,6) Man-made materials,45,PPT学习交流,Substitution for traditional structural metals,46,PPT学习交流,Qustions,please illustrate two type of eleme

22、nts that composed ceramic compounds in periodic table. What are the major compositions 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 ceramic

23、s according their atomic structrual feature. What are polymers? What are characteristics of polymers? Please give some examples of polymers.,47,PPT学习交流,48,PPT学习交流,SiO2 (approximately 72%) Na2O CaO,Glass:,brittleness,similar with crystalline ceramic,49,PPT学习交流,According to their compositions, ceramic

24、s 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.,50,PPT学习交流,according to their atomic structual feature, there are three types of

25、 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 lithium alumi

26、nosilicates ) can be fully devitified by an appropriate thermal treatment.,51,PPT学习交流,Polymers are long-chain molecules composed of many mers bond together. Polyethylene, acrylics and nylon are all typical polymers. Polymers are no brittleness, high strength along its chain and low strength between

27、its chains, lightweight, low-cost, lower melting point and higher chemical reactivity compared with ceramics, at last polymers are man-made materials.,52,PPT学习交流,shell,53,PPT学习交流,wood,54,PPT学习交流,55,PPT学习交流,56,PPT学习交流,D Composite (fiber reinforce plastics),Possessing hereditaryhI5redItErI rank in a p

28、olitical 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 2,57,PPT学习交流,Combination of individual materials from the previou

29、s 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.,58,PPT学习交流,Example: fiberglass ,wood ,concrete .,59,PPT学习交流,60,PPT学习交流,s,61,PPT学习交流,Supplementary introduction

30、 Semiconductors,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,62,PPT学习交流,Sophist

31、icated 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 latest and most sophisticated technology.,63,PPT学习交流,Semiconductors are relatively invisible compared with polymers , but have a comparable social impact. Semiconductors are the b

32、asis of modern electronics.,64,PPT学习交流,65,PPT学习交流,A relatively small group 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 5sQlfai

33、d ceramics compound : ZnO Precise control of chemical purity allows precise control of electronic properties.,66,PPT学习交流,Characteristics: semiconduction, in which they are neither good electrical conductors nor good electrical insulators 5insjuleitE , instead, their ability to conduct electricity is

34、 intermediate 7intE5mi:djEt.,67,PPT学习交流,Atomic-scale-architecture Composite Devitrifieddi:5vitrifai 使不透明 Ductility Electronic and magnetic material Fiberglass Materials selection Microcircuitry 5maIkrEJs:kIt电子微电路 Microscopic-scale architecture Refractory Structural material,68,PPT学习交流,Qustions,1、Ple

35、ase define composites, and then demonstrate the characteristics of good composites by some examples. 2、please enumerate ( i5nju:mEreit v.列举) semiconducting elements and compounds.,69,PPT学习交流,Composite is material composed of a microscopic-scale combination of individual materials from the categories

36、 of metals, ceramics (and glasses), and polymer. E.g. fiberglass is a kind of composite system composed of polymeric matrix reinforced with glass fibers. Characteristic of fiberglass provides the best of both worlds: It carry along the superior properties of each component, producing a product that

37、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 produce a strong material capable of withstanding the normal loading required of a structural material.,70,PPT学习交流,There are three semicond

38、ucting 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 semiconducting. Examples include gallium arsenide (GaAs), which is used as a high-temperature rectifier (5rektifaiE 整流器) and a laser mate

39、rial, and cadmium sulfide (CdS) which is used as a relatively low-cost solar cell for conversion of solar energy to useful electrical energy.,71,PPT学习交流,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

40、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，等于一烛光的均匀点光源在单位主体角内发出的光通量.,72,PPT学习交流,Equivalent i5kwivElEnt adj. 相等的, 相当的, 同意义的 等价物, 相等物 Avenue 5Avinju: n. 林荫

41、道, 大街, 方法, 途径, 路 Refraction ri5frAkFEn n. 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,73,PPT学习交流,Translucent trAnz5lju:snt adj. 半透明的, 透明的 Opaque Eu5peik n. 不透明物 adj.不透明的, 不传热的, 迟钝的 Transparent trAns5pZErEnt adj. 透明的, 显然的, 明晰的 Densification 7densifi5keiFEn 致密化,

42、74,PPT学习交流,To understand the properties of engineering materials it is necessary to understand their structure .,75,PPT学习交流,Atomic-scale architecture 10000000 times,Microscopic-scale architecture 1000times,76,PPT学习交流,Example 1: Al , Mg Al alloys are ductile Mg alloys are brittle,77,PPT学习交流,Al struct

43、ure follows a cubic packing arrangement and Mg a hexagonal one .,78,PPT学习交流,79,PPT学习交流,80,PPT学习交流,Example 2: transparent ceramics Traditional ceramics contained a substantial amount of residual porosity . The porosity leads to loss of visible light transmission . Only about 0.3% porosity can cause A

44、l2O3 to be translucent , and 3% porosity can cause the material to be completely opaque . The elimination of porosity :,adding a small amount of impurity .,81,PPT学习交流,The elimination of porosity resulted from a relatively simple invention that involved adding a small amount of impurity (0.1 wt% MgO)

45、, which caused the high-temperature densification process for the Al2O3 powder to go to completion.,82,PPT学习交流,Poros microstructure in polycrystalline Al2O3,83,PPT学习交流,Figure 1polycrystalline faceted sapphires and rubies,Figure 3polished discs with several dopants (thickness: 0.8 mm),84,PPT学习交流,85,P

46、PT学习交流,The two examples just cited show typical and important demonstrations of how properties of engineering materials follow directly from structure.,86,PPT学习交流,Qustions,1. Aluminum and magnesium are both metal, why aluminum is relatively ductile while magnesium is relatively brittle? Please expla

47、in the dramatic effect that structure has on properties on the atomic scale. 2. why traditional ceramics such as aluminum oxide are opaque whereas recently optically transparent aluminum oxide ceramics are produced? What are the differences between their microscopic-scale architectures?,87,PPT学习交流,1

48、.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 .,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

49、 added . and so forth, and so on, and the others,2 . ASTM,American Society for Testing and Materials.,3 . aramid,88,PPT学习交流,A polymer containing repeated amide groups, as in various kinds of nylon.,4 . Aromatic 7ArEu5mAtik,Of, relating to, or containing one or more six-carbon rings characteristic of

50、 the benzene 5benzi:n, ben5zi:n series and related organic groups.,5 . Polyamide,89,PPT学习交流,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. Materials selection is the final, practical decision in the engineering design process and can determine tha

51、t 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),90,PPT学习交流,5.although some structural ceramics can withstand the anticipated service 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,91,PPT学习交流,7. The added cost of fabricating these more sophisticated material systems is justified only if a special advantage results. fabricate 5fAbr