unit1先进工程材料

1、Professional English 北华大学机械学院王开宝Unit 1 Types of Materials材料的类型 Materials may be grouped in several ways. Scientists often classify materials by their state: solid, liquid, or gas. They also separate them into organic (once living) and inorganic (never living) materials. 材料可以按多种方法分类。科学家常根据状态将材料分为：固体、

2、液体或气体。他们也把材料分为有机材料(曾经有生命的)和无机材料(从未有生命的)。 For industrial purposes, materials are divided into engineering materials or non-engineering materials. Engineering materials are those used in manufacture and become parts of products. 就工业用途而言，材料被分为工程材料和非工程材料。那些用于加工制造并成为产品组成部分的就是工程材料。Non-engineering material

3、s are the chemicals, fuels, lubricants, and other materials used in the manufacturing process, which do not become part of the product. 非工程材料则是化学品、燃料、润滑剂以及其它用于加工制造过程但不成为产品组成部分的材料。Engineering materials may be further subdivided into: Metal Ceramics Composite Polymers, etc. 工程材料还能进一步细分为：金属材料陶瓷材料复合材料 聚

4、合材料，等等。Subdivide v. 再分, 细分To divide a part or parts of into smaller parts.再分：把（正分开的东西）进一步分成或细分To divide into a number of parts, especially to divide (land) into lots.把分或几块：把分成几份，尤指把（一块地）分成几块小块To form into subdivisions.再分，细分：被再分，被剖分Polymer n.聚合体Any of numerous natural and synthetic compounds of usual

5、ly high molecular weight consisting of up to millions of repeated linked units, each a relatively light and simple molecule.聚合物：许多天然和人工合成的化合物中的任一种，通常具高分子的重量，包含最多可达上百万个的彼此重复且相连的单位，每一个单位都是一个相对较轻和较简单的分子Composite adj. 合成的, 复合的 n. 合成物Made up of distinct components; compound.合成的：不同成分组成的；混合的Metals and Meta

6、l Alloys 金属和金属合金Metals are elements that generally have good electrical and thermal conductivity. Many metals have high strength, high stiffness, and have good ductility. 金属就是通常具有良好导电性和导热性的元素。许多金属具有高强度、高硬度以及良好的延展性。Some metals, such as iron, cobalt and nickel, are magnetic. At low temperatures, some

7、metals and intermetallic compounds become superconductors. 某些金属能被磁化，例如铁、钴和镍。在极低的温度下，某些金属和金属化合物能转变成超导体。What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table. Examples of pure metals include copper in electrical wires

8、 and aluminum in cooking foil and beverage cans. 合金与纯金属的区别是什么？纯金属是在元素周期表中占据特定位置的元素。例如电线中的铜和制造烹饪箔及饮料罐的铝。Alloys contain more than one metallic element. Their properties can be changed by changing the elements present in the alloy. Examples of metal alloys include stainless steel which is an alloy of i

9、ron, nickel, and chromium; and gold jewelry which usually contains an alloy of gold and nickel. 合金包含不止一种金属元素。合金的性质能通过改变其中存在的元素而改变。金属合金的例子有：不锈钢是一种铁、镍、铬的合金，以及金饰品通常含有金镍合金。 Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-t

10、o-volume ratio. 为什么要使用金属和合金？许多金属和合金具有高密度，因此被用在需要较高质量体积比的场合。Some metal alloys, such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy. Many alloys also have high fracture toughness, which means they can withstand impact and are durable. 某些金属合金，例如铝基

11、合金，其密度低，可用于航空航天以节约燃料。许多合金还具有高断裂韧性，这意味着它们能经得起冲击并且是耐用的。 What are some important properties of metals?DensityDensity is defined as a materials mass divided by its volume. Most metals have relatively high densities, especially compared to polymers. 金属有哪些重要特性？ 密度密度定义为材料的质量与其体积之比。大多数金属密度相对较高，尤其是和聚合物相比较而言。

12、Polymer Any of numerous natural and synthetic compounds of usually high molecular weight consisting of up to millions of repeated linked units, each a relatively light and simple molecule.聚合物：许多天然和人工合成的化合物中的任一种，通常具高分子的重量，包含最多可达上百万个的彼此重复且相连的单位，每一个单位都是一个相对较轻和较简单的分子Materials with high densities often c

13、ontain atoms with high atomic numbers, such as gold or lead. However, some metals such as aluminum or magnesium have low densities, and are used in applications that require other metallic properties but also require low weight. 高密度材料通常由较大原子序数原子构成，例如金和镁。然而，诸如铝和镁之类的一些金属则具有低密度，并被用于既需要金属特性又要求重量轻的场合。提示：

14、不要尝试用翻译软件翻译具有复杂语法结构的句子。金山词霸翻译结果：金山词霸翻译结果：高密度，常含有高原子序数的材料，如金或铅。然而，某些金属如铝或高密度，常含有高原子序数的材料，如金或铅。然而，某些金属如铝或镁的密度低，并用于需要金属特性又要求重量轻的应用镁的密度低，并用于需要金属特性又要求重量轻的应用 Fracture toughnessFracture toughness can be described as a materials ability to avoid fracture, especially when a flaw is introduced. Metals can gen

15、erally contain nicks and dents without weakening very much, and are impact resistant. A football player counts on this when he trusts that his facemask wont shatter. 断裂韧性断裂韧性可以描述为材料防止断裂特别是出现缺陷时不断裂的能力。金属一般能在有缺口和凹痕的情况下不显著削弱，并且能抵抗冲击。橄榄球运动员据此相信他的面罩不会裂成碎片。 Plastic deformationPlastic deformation is the ab

16、ility of bend or deform before breaking. As engineers, we usually design materials so that they dont deform under normal conditions. You dont want your car to lean to the east after a strong west wind. 塑性变形塑性变形就是在断裂前弯曲或变形的能力。作为工程师，设计时通常要使材料在正常条件下不变形。没有人愿意一阵强烈的西风过后自己的汽车向东倾斜。However, sometimes we can

17、take advantage of plastic deformation. The crumple zones in a car absorb energy by undergoing plastic deformation before they break. 然而，有时我们也能利用塑性变形。汽车上压皱的区域在它们断裂前通过经历塑性变形来吸收能量。 Crumple v. 弄皱, 压皱, 变皱, 崩溃, 垮台To crush together or press into wrinkles; rumple.挤压：挤在一起或压出皱纹；弄皱To cause to fall apart.使破裂To

18、become wrinkled.变皱To fall apart; collapse:破裂；崩溃：The atomic bonding of metals also affects their properties. In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere. Since electrons conduct heat and electricity, metals make good cooking pans and electrical

19、 wires. 金属的原子连结对它们的特性也有影响。在金属内部，原子的外层价电子由所有原子共享并能到处自由移动。由于电子能导热和导电，所以用金属可以制造好的烹饪锅和电线。Valence velns n. 化(化合)价, 原子价The combining capacity of an atom or a radical determined by the number of electrons that it will lose, add, or share when it reacts with other atoms.化合价，原子价：原子或原子团与其它原子结合的能力是由它在与其它的原子结合时

20、所丢失、增加或共享的电子的数目决定的。It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal. No photons pass through. 因为这些价电子吸收到达金属的光子，所以透过金属不可能看得见。没有光子能通过金属。AlloysAlloys are compounds consisting of more than one metal. Adding other metals can affect th

21、e density, strength, fracture toughness, plastic deformation, electrical conductivity and environmental degradation. 合金合金是由一种以上金属组成的混合物。加一些其它金属能影响密度、强度、断裂韧性、塑性变形、导电性以及环境侵蚀。For example, adding a small amount of iron to aluminum will make it stronger. Also, adding some chromium to steel will slow the

22、rusting process, but will make it more brittle. 例如，往铝里加少量铁可使其更强。同样，在钢里加一些铬能减缓它的生锈过程，但也将使它更脆。Photon n. 物光子The quantum of electromagnetic energy, generally regarded as a discrete particle having zero mass, no electric charge, and an indefinitely long lifetime.See table at subatomic particle 光子，光量子：电磁能

23、的量子，一般认为是有零质量、无电荷和不定长寿命的离散性粒子参见 subatomic particleA unit of retinal illumination, equal to the amount of light that reaches the retina through 1 square millimeter of pupil area from a surface having a brightness of 1 candela per square meter.光度：视网膜亮度单位，相当于每平方米有一烛光亮度的表面，通过一平方毫米的瞳孔区域，到达视网膜的光线数量Ceramic

24、s and Glasses陶瓷和玻璃A ceramic is often broadly defined as any inorganic nonmetallic materialBy this definition, ceramic materials would also include glasses; however, many materials scientists add the stipulation that “ceramic” must also be crystalline. 陶瓷通常被概括地定义为无机的非金属材料。照此定义，陶瓷材料也应包括玻璃；然而许多材料科学家添加了

25、“陶瓷”必须同时是晶体物组成的约定。A glass is an inorganic nonmetallic material that does not have a crystalline structure. Such materials are said to be amorphous. 玻璃是没有晶体状结构的无机非金属材料。这种材料被称为非结晶质材料。Properties of Ceramics and Glasses陶瓷和玻璃的特性Some of the useful properties of ceramics and glasses include high melting te

26、mperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance. 高熔点、低密度、高强度、高刚度、高硬度、高耐磨性和抗腐蚀性是陶瓷和玻璃的一些有用特性。Stipulation n. 约定, 约束, 契约 The act of stipulating.制定：制定的行为Something stipulated, especially a term or condition in an agreement.条款：规定的东西，尤指约定中的条款或条件Amorphou

27、s adj. 无定形的, 无组织的Lacking distinct crystalline structure.非结晶质的：没有明确结晶结构的Many ceramics are good electrical and thermal insulators. Some ceramics have special properties: some ceramics are magnetic materials; some are piezoelectric materials; and a few special ceramics are superconductors at very low t

28、emperatures. Ceramics and glasses have one major drawback: they are brittle. 许多陶瓷都是电和热的良绝缘体。某些陶瓷还具有一些特殊性能：有些是磁性材料，有些是压电材料，还有些特殊陶瓷在极低温度下是超导体。陶瓷和玻璃都有一个主要的缺点：它们容易破碎。Insulator n. 绝缘体, 绝热器A material that insulates, especially a nonconductor of sound, heat, or electricity. 绝缘体：绝缘材料，特别是声、热、电的非导体A device th

29、at insulates. 绝缘装置Ceramics are not typically formed from the melt. This is because most ceramics will crack extensively (i.e. form a powder) upon cooling from the liquid state. 陶瓷一般不是由熔化形成的。因为大多数陶瓷在从液态冷却时将会完全破碎(即形成粉末)。Piezoelectric 物压电的Hence, all the simple and efficient manufacturing techniques use

30、d for glass production such as casting and blowing, which involve the molten state, cannot be used for the production of crystalline ceramics. Instead, “sintering” or “firing” is the process typically used. 因此，所有用于玻璃生产的简单有效的诸如浇铸和吹制这些涉及熔化的技术都不能用于由晶体物组成的陶瓷的生产。作为替代，一般采用“烧结”或“焙烧”工艺。Sintering v. 烧结 n. 烧结

31、, 热压In sintering, ceramic powders are processed into compacted shapes and then heated to temperatures just below the melting point. At such temperatures, the powders react internally to remove porosity and fully dense articles can be obtained. 在烧结过程中，陶瓷粉末先挤压成型然后加热到略低于熔点温度。在这样的温度下，粉末内部起反应去除孔隙并得到十分致密的

32、物品。Porosity p:rsti n. 多孔性, 有孔性The state or property of being porous.有孔性，多孔性：有孔或多孔的状态或特性A structure or part that is porous. 多孔部分或多孔结构The ratio of the volume of all the pores in a material to the volume of the whole.孔隙率：一材料中孔隙的总体积与整个材料的体积之间的比率 An optical fiber contains three layers: a core made of hig

33、hly pure glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage. 光导纤维有三层：核心由高折射指数高

34、纯光传输玻璃制成，中间层为低折射指数玻璃，是保护核心玻璃表面不被擦伤和完整性不被破坏的所谓覆层，外层是聚合物护套，用于保护光导纤维不受损。refractive index 折射率Cladding n. 覆层金山词霸翻译结果：光导纤维有三层：由具有高折射率的光指数高纯金山词霸翻译结果：光导纤维有三层：由具有高折射率的光指数高纯玻璃芯，中间层的玻璃具有较低的折射率称为保护从划痕和其它表面玻璃芯，中间层的玻璃具有较低的折射率称为保护从划痕和其它表面缺陷核心玻璃包层，和聚合物护套保护光纤免受损害。缺陷核心玻璃包层，和聚合物护套保护光纤免受损害。In order for the core glass t

35、o have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light. 为了使核心玻璃有比覆层大的折射指数，在其中掺入微小的、可控数量的能减缓光速而不会吸收光线的杂质或搀杂剂。Dopant A substance, such as boron, added in s

36、mall amounts to a pure semiconductor material to alter its conductive properties for use in transistors and diodes.掺杂质，掺质剂：加入纯半导体材料中的少量硼等物质，用于晶体管和二极管中以改变半导体的导电率Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the co

37、re glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle. 由于核心玻璃的折射指数比覆层大，只要在全内反射过程中光线照射核心/覆层分界面的角度比临界角大，在核心玻璃中传送的光线将仍保留在核心玻璃中。The total internal reflection phenomenon, as well as the high purity of the core glass,

38、 enables light to travel long distances with little loss of intensity. 全内反射现象与核心玻璃的高纯度一样，使光线几乎无强度损耗传递长距离成为可能。Composites 复合材料Composites are formed from two or more types of materials. Examples include polymer/ceramic and metal/ceramic composites. Composites are used because overall properties of the

39、composites are superior to those of the individual components. 复合材料由两种或更多材料构成。例子有聚合物/陶瓷和金属/陶瓷复合材料。之所以使用复合材料是因为其全面性能优于组成部分单独的性能。For example: polymer/ceramic composites have a greater modulus than the polymer component, but arent as brittle as ceramics.Two types of composites are: fiber-reinforced com

40、posites and particle-reinforced composites.例如：聚合物/陶瓷复合材料具有比聚合物成分更大的模量，但又不像陶瓷那样易碎。 复合材料有两种：纤维加强型复合材料和微粒加强型复合材料。Fiber-reinforced Composites纤维加强型复合材料Reinforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers. Fibers increase t

41、he modulus of the matrix material. 加强纤维可以是金属、陶瓷、玻璃或是已变成石墨的被称为碳纤维的聚合物。纤维能加强基材的模量。Matrix n. (生物形成生长的)母体, 母体组织;【解】子宫 发源地, 策源地 【生】细胞间质, 基质 【矿】母岩, 杂矿石, 基岩;【地质】脉石, 填质; (岩石中化石等的)痕印 【冶】(合金的)基体 【刷】纸型, 字模 唱片模子 【数】阵, 矩阵, 真值表, 母式;【无】矩阵变换电路; 【语】主句、独立句The strong covalent bonds along the fibers length give them a

42、very high modulus in this direction because to break or extend the fiber the bonds must also be broken or moved. 沿着纤维长度有很强结合力的共价结合在这个方向上给予复合材料很高的模量，因为要损坏或拉伸纤维就必须破坏或移除这种结合。Fibers are difficult to process into composites, making fiber-reinforced composites relatively expensive. 把纤维放入复合材料较困难，这使得制造纤维加强型

43、复合材料相对昂贵。Covalent adj. 化共有原子价的, 共价的covalent bond 共价键Thermoset n. 热固树脂,热固塑料 adj. 热固的Thermoplastic adj. 热塑性的 n. 热塑性塑料Becoming soft when heated and hard when cooled.热塑的：加热时变软冷却时变硬的Fiber-reinforced composites are used in some of the most advanced, and therefore most expensive sports equipment, such as a

44、 time-trial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix. 纤维加强型复合材料用于某些最先进也是最昂贵的运动设备，例如计时赛竞赛用自行车骨架就是用含碳纤维的热固塑料基材制成的。Body parts of race cars and some automobiles are composites made of glass fibers (or fiberglass) in a thermoset matrix. 竞赛用汽车和某些机动车的车体部件是由含玻璃纤维(或玻

45、璃丝)的热固塑料基材制成的。Fibers have a very high modulus along their axis, but have a low modulus perpendicular to their axis. Fiber composite manufacturers often rotate layers of fibers to avoid directional variations in the modulus. 纤维在沿着其轴向有很高的模量，但垂直于其轴向的模量却较低。纤维复合材料的制造者往往旋转纤维层以防模量产生方向变化。Particle-reinforced

46、 composites 微粒加强型复合材料Particles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous materials, including polymers and carbon black. 用于加强的微粒包含了陶瓷和玻璃之类的矿物微粒，铝之类的金属微粒以及包括聚合物和碳黑的非结晶质微粒。Particles are used to increase the modulu

47、s of the matrix, to decrease the permeability of the matrix, to decrease the ductility of the matrix. An example of particle-reinforced composites is an automobile tire which has carbon black particles in a matrix of polyisobutylene elastomeric polymer. 微粒用于增加基材的模量、减少基材的渗透性和延展性。微粒加强型复合材料的一个例子是汽车轮胎，它

48、就是在聚异丁烯人造橡胶聚合物基材中加入了碳黑微粒。Polyisobutylene plasbju:tli:n n. 化聚异丁烯Elastomeric lstmerk adj. 弹性体的, 人造橡胶的Polymers 聚合材料l A polymer has a repeating structure, usually based on a carbon backbone. The repeating structure results in large chainlike molecules. Polymers are useful because they are lightweight, c

49、orrosion resistant, easy to process at low temperatures and generally inexpensive.l 聚合物具有一般是基于碳链的重复结构。这种重复结构产生链状大分子。由于重量轻、耐腐蚀、容易在较低温度下加工并且通常较便宜，聚合物是很有用的。Some important characteristics of polymers include their size (or molecular weight), softening and melting points, crystallinity, and structure. Th

50、e mechanical properties of polymers generally include low strength and high toughness. Their strength is often improved using reinforced composite structures. 聚合材料具有一些重要特性，包括尺寸(或分子量)、软化及熔化点、结晶度和结构。聚合材料的机械性能一般表现为低强度和高韧性。它们的强度通常可采用加强复合结构来改善。Important Characteristics of Polymers聚合材料的重要特性Size.Size. Sing

51、le polymer molecules typically have molecular weights between 10,000 and 1,000,000g/molthat can be more than 2,000 repeating units depending on the polymer structure! 尺寸：尺寸：单个聚合物分子一般分子量为10,000到1,000,000g/mol之间，具体取决于聚合物的结构这可以比2,000个重复单元还多。The mechanical properties of a polymer are significantly affec

52、ted by the molecular weight, with better engineering properties at higher molecular weights. 聚合物的分子量极大地影响其机械性能，分子量越大，工程性能也越好。 Thermal transitions.Thermal transitions. The softening point (glass transition temperature) and the melting point of a polymer will determine which it will be suitable for ap

53、plications. These temperatures usually determine the upper limit for which a polymer can be used.热转换性：热转换性：聚合物的软化点(玻璃状转化温度)和熔化点决定了它是否适合应用。这些温度通常决定聚合物能否使用的上限。For example, many industrially important polymers have glass transition temperatures near the boiling point of water (100, 212 ), and they are

54、most useful for room temperature applications. Some specially engineered polymers can withstand temperatures as high as 300(572 ). 例如，许多工业上的重要聚合物其玻璃状转化温度接近水的沸点(100, 212 )，它们被广泛用于室温下。而某些特别制造的聚合物能经受住高达300(572 )的温度。摄氏度 （华氏度 ） 华氏度 摄氏度 Celsius adj. 摄氏的 缩写 COf or relating to a temperature scale that registers the freezing point of water as 0= and the boiling point as 100= under normal atmospheric pressure.See table at measurement 摄氏的：将正常大气压下水的冰点作为0=C、沸点作为100=C的一种温标的，或与之相关的参见 measurementSwedish astronomer who devised (1742) the ce