《材料科学概论》PPT课件.ppt

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 sections The fundamentals The structural materials The electronic and magnetic materials Materials in engineering design,Nature of materials properties,Microscopic or submicroscopic structure,Engineering design,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,Key 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,Glass Glass-ceramic Insulator Materials science and engineering Materials selection Metallic Microcircuitry 5maIkrEJs:kIt Microscopic-scale architecture Noncrystalline Nonmetallic 5nCnmi5tAlik,Key word,Oxide PeriodicpiEri5Cdik table Plastic Polyethylene 7pCli5eWili:n Polymer Property Refractory Semiconductor Silica硅石，SiO2 Silicate硅酸盐 Silicon硅元素 Steel,Structural material wood,Key word,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 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.,Characteristics(metallic 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,Gasket 5Askit 垫圈, 衬垫,spring,wire,Valve vAlv,B Ceramics si5rAmiks,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 . Devitrify di:5vitrifai,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 tension electrical insulators ; structural clay products ; nuclear ceramics ; whitewares ; abrasives E5breisiv .,The Different Colors of Corundum kE5rQndEm,Ruby,Sapphire 5sAfaiE,Why shouldnt Al2O3 be chosen for certain applications 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,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 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 their 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:baid Nitride 5naitraid Oxide 5Cksaid Phosphide 5fCsfaid Sulphide. 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 atoms 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 category Lithium aluminosilicates Certain glass compositions can be fully devitified by an appropriate thermal treatment,low-thermal expansion coefficients,complex forms,high mechanical strength,Vitreous 5vItrIEs,glassy state,Subsequent crystallization,C 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 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 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 materials 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 chain 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? 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 characteristics of polymers? Please 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 one 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 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 and 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 reinforce 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 individual 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,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 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.,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 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 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-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,Qustions,1、Please 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.,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. Characteristic 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 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 semiconducting. 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 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 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,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,To understand the properties of engineering materials it is necessary to understand their structure .,Atomic-scale architecture 10000000 times,Microscopic-scale architecture 1000times,Example 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 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 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 .,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 Al2O3 powder to go to completion.,Poros microstructure in polycrystalline Al2O3,Figure 1 polycrystalline faceted sapphires and rubies,Figure 3 polished discs with several dopants (thickness: 0.8 mm),The two examples just cited show typical and important demonstrations of how properties of engineering materials 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 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 .,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 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. Materials 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 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,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 prove 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 kEm5pArisn 10. 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 include 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 me5tAlEdVi n. 冶金, 冶金术 13. optimum 5CptimEm n.最适宜 adj.最适宜的,Which material do I now select for a particular application ?,Two separate decisions: First: One must decide which type of material is appropriate. Second: The best specific material within that category must be found. preferable 5prefErEbl adj.更可取的, 更好的, 更优越的,A . Competition among the five types of materials,B . Selecting an optimal metal property comparisons must be made,2 . Cost,1 . Superior mechanical properties,c. Selecting a metal substitute,1.4 materials science and engineering,First : science Second : materials Finally : engineering,大学课件出品 版权归原作者所有 联系QQ ：910670854 如侵权，请告知，吾即删 更多精品文档请访问我的个人主页 /611696569,附赠人生心语,人生太短，聪明太晚,人生太短，聪明太晚(1),我们都老得太快 却聪明得太迟 把钱省下来，等待退休后再去享受 结果退休后，因为年纪大，身体差，行动不方便，哪里也去不成。钱存下来等养老，结果孩子长大了，要出国留学，要创业做生意，要花钱娶老婆，自己的退休金都被拗走了。,人生太短，聪明太晚(2),当自己有足够的能力善待自己时，就立刻去做，老年人有时候是无法做中年人或是青少年人可以做的事，年纪和健康就是一大因素。小孩子从小就告诉他，养你到高中，大学以后就要自立更生，要留学，创业，娶老婆，自己想办法，自己要留多一点钱，不要为了小孩子而活我们都老得太快却聪明得太迟，我的学长去年丧妻。这突如其来的事故，实在叫人难以接受，但是死亡的到来不总是如此。学长说他太太最希望他能送鲜花给他，但是他觉得太浪费，总推说等到下次再买，结果却是在她死后，用鲜花布置她的灵堂。这不是太蠢愚了吗？！ 等到、等到.，似乎我们所有的生命，都用在等待。,人生太短，聪明太晚(3),等到我大学毕业以后，我就会如何如何我们对自己说 等到我买房子以后！ 等我最小的孩子结婚之后！ 等我把这笔生意谈成之后！ 等到我死了以后 人人都很愿意牺牲当下，去换取未知的等待；牺牲今生今世的辛苦钱，去购买后世的安逸 在台湾只要往有山的道路上走一走，就随处都可看到农舍变精舍，山坡地变灵塔，无非也是为了等到死后，能图个保障，不必再受苦。许多人认为必须等到某时或某事完成之后再采取行动。明天我就开始运动，明天我就会对他好一点，下星期我们就找时间出去走走；退休后，我们就要好好享受一下。,人生太短，聪明太晚(4),然而，生活总是一直变动，环境总是不可预知，现实生活中，各种突发状况总是层出不穷。身为一个医生，我所见过的死人，比一般人要来得多。这些人早上醒来时，原本预期过的是另一个平凡无奇的日子，没想到一个意料之外的事；交通意外、脑溢血、心脏病发作等等。剎那间生命的巨轮倾覆离轨，突然闯进一片黑暗之中。那么我们要如何面对生命呢？我们毋需等到生活完美无瑕，也毋需等到一切都平稳，想做什么，现在就可以开始做起。 一个人永远也无法预料未来，所以不要延缓想过的生活，不要吝于表达心中的话， 因为生命只在一瞬间。,人生太短，聪明太晚(5),记住！ 给活人送一朵鲜花，强过给死人送贵重的花圈，每个人的生命都有尽头，许多人经常在生命即将结束时，才发现自己还有很多事没有做，有许多话来不及说，这实在是人生最大的遗憾。 别让自己徒留为时已晚的空余恨。逝者不可追，来者犹未卜，最珍贵、最需要实时掌握的当下，往往在这两者蹉跎间，转眼错失。,人生太短，聪明太晚(6),人生短暂飘忽，包得有一首小诗这样写： 高天与原地，悠悠人生路； 行行向何方，转眼即长暮。 正是道尽了人生如寄，转眼即逝的惶恐。 有许多事，在你还不懂得珍惜之前已成旧事；有许多人，在你还来不及用心之前 已成旧人。 遗憾的事一再发生，但过后再追悔早知道如何如何是没有用的，那时候已经过去，你追念的人也已走过了你。,人生太短，聪明太晚(7),一句瑞典格言说：我们老得太快，却聪明得太迟。 不管你是否察觉，生命都一直在前进。 人生并未售来回票，失去的便永远不再得到。 将希望寄予等到方便的时间才享受,人生太短，聪明太晚(8),我们不知失去了多少可能的幸福 不要再等待有一天你可以松口气，或是麻烦都过去了。 生命中大部分的美好事物都是短暂易逝的， 享受它们、品尝它们， 善待你周