unit1--先進工程材料

1、Professional English,北華大學機械學院王開寶,Unit 1 Types of Materials材料的類型,Materials may be grouped in several ways. Scientists often classify materials by their state: solid, liquid, or gas. They also separate them into organic

2、(once living) and inorganic (never living) materials. 材料可以按多種方法分類。科學家常根據(jù)狀態(tài)將材料分為：固體、液體或氣體。他們也把材料分為有機材料(曾經有生命的)和無機材料(從未有生命的)。,For industrial purposes, materials are divided into engineering materials or non-enginee

3、ring materials. Engineering materials are those used in manufacture and become parts of products. 就工業(yè)用途而言，材料被分為工程材料和非工程材料。那些用于加工制造并成為產品組成部分的就是工程材料。Non-engineering materials are the chemicals, fuels, lubricants, and

4、 other materials used in the manufacturing process, which do not become part of the product. 非工程材料則是化學品、燃料、潤滑劑以及其它用于加工制造過程但不成為產品組成部分的材料。,Engineering materials may be further subdivided into: ①Metal ②Ceramics ③Composi

5、te ④Polymers, etc. 工程材料還能進一步細分為：①金屬材料②陶瓷材料③復合材料 ④聚合材料，等等。,Subdivide v. 再分, 細分To divide a part or parts of into smaller parts.再分：把（正分開的東西）進一步分成或細分To divide into a number of parts, especially to divide (land) into l

6、ots.把…分或幾塊：把…分成幾份，尤指把（一塊地）分成幾塊小塊To form into subdivisions.再分，細分：被再分，被剖分,Polymer n.聚合體Any of numerous natural and synthetic compounds of usually high molecular weight consisting of up to millions of repeated linked u

7、nits, each a relatively light and simple molecule.聚合物：許多天然和人工合成的化合物中的任一種，通常具高分子的重量，包含最多可達上百萬個的彼此重復且相連的單位，每一個單位都是一個相對較輕和較簡單的分子Composite adj. 合成的, 復合的 n. 合成物Made up of distinct components; compound.合成的：不同成分組成的；混合的

8、,Metals and Metal Alloys 金屬和金屬合金,Metals are elements that generally have good electrical and thermal conductivity. Many metals have high strength, high stiffness, and have good ductility. 金屬就是通常具有良好導電性和導熱性的元素。許多金屬具

9、有高強度、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 metals and intermetallic compounds become superconductors. 某些金屬能被磁化，例如鐵、鈷和鎳。在極低的溫度下，某些金屬和金屬化合物能轉變成超導體。,What is t

10、he 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 and aluminum in cooking foil a

11、nd beverage cans. 合金與純金屬的區(qū)別是什么？純金屬是在元素周期表中占據(jù)特定位置的元素。例如電線中的銅和制造烹飪箔及飲料罐的鋁。,Alloys contain more than one metallic element. Their properties can be changed by changing the elements present in the alloy. Examples of meta

12、l alloys include stainless steel which is an alloy of iron, nickel, and chromium; and gold jewelry which usually contains an alloy of gold and nickel. 合金包含不止一種金屬元素。合金的性質能通過改變其中存在的元素而改變。金屬合金的例子有：不銹鋼是一種鐵、鎳、鉻的合金，以及金飾品通常

13、含有金鎳合金。,Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio. 為什么要使用金屬和合金？許多金屬和合金具有高密度，因此被用在需要較高質量體積比的場合。Some metal alloy

14、s, 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

15、金屬合金，例如鋁基合金，其密度低，可用于航空航天以節(jié)約燃料。許多合金還具有高斷裂韌性，這意味著它們能經得起沖擊并且是耐用的。,What are some important properties of metals?Density is defined as a material’s mass divided by its volume. Most metals have relatively high densities, espe

16、cially compared to polymers. 金屬有哪些重要特性？ 密度定義為材料的質量與其體積之比。大多數(shù)金屬密度相對較高，尤其是和聚合物相比較而言。,Polymer Any of numerous natural and synthetic compounds of usually high molecular weight consisting of up to millions of repeate

17、d linked units, each a relatively light and simple molecule.聚合物：許多天然和人工合成的化合物中的任一種，通常具高分子的重量，包含最多可達上百萬個的彼此重復且相連的單位，每一個單位都是一個相對較輕和較簡單的分子,Materials with high densities often contain atoms with high atomic numbers, such as

18、 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. 高密度材料通常由較大原子序數(shù)原子構成，例如金和鎂。然而，諸如鋁和鎂

19、之類的一些金屬則具有低密度，并被用于既需要金屬特性又要求重量輕的場合。,提示：不要嘗試用翻譯軟件翻譯具有復雜語法結構的句子。,金山詞霸翻譯結果：高密度，常含有高原子序數(shù)的材料，如金或鉛。然而，某些金屬如鋁或鎂的密度低，并用于需要金屬特性又要求重量輕的應用,Fracture toughness can be described as a material’s ability to avoid fracture, especially w

20、hen a flaw is introduced. Metals can generally contain nicks and dents without weakening very much, and are impact resistant. A football player counts on this when he trusts that his facemask won’t shatter. 斷裂韌性可以描述為

21、材料防止斷裂特別是出現(xiàn)缺陷時不斷裂的能力。金屬一般能在有缺口和凹痕的情況下不顯著削弱，并且能抵抗沖擊。橄欖球運動員據(jù)此相信他的面罩不會裂成碎片。,Plastic deformation is the ability of bend or deform before breaking. As engineers, we usually design materials so that they don’t deform under nor

22、mal conditions. You don’t want your car to lean to the east after a strong west wind. 塑性變形就是在斷裂前彎曲或變形的能力。作為工程師，設計時通常要使材料在正常條件下不變形。沒有人愿意一陣強烈的西風過后自己的汽車向東傾斜。,However, sometimes we can take advantage of plastic deformation.

23、 The crumple zones in a car absorb energy by undergoing plastic deformation before they break. 然而，有時我們也能利用塑性變形。汽車上壓皺的區(qū)域在它們斷裂前通過經歷塑性變形來吸收能量。,Crumple v. 弄皺, 壓皺, 變皺, 崩潰, 垮臺To crush together or press into wrinkles; rump

24、le.擠壓：擠在一起或壓出皺紋；弄皺To cause to fall apart.使破裂To become wrinkled.變皺To fall apart; collapse:破裂；崩潰：,The atomic bonding of metals also affects their properties. In metals, the outer valence electrons are shared among all

25、atoms, and are free to travel everywhere. Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires. 金屬的原子連結對它們的特性也有影響。在金屬內部，原子的外層價電子由所有原子共享并能到處自由移動。由于電子能導熱和導電，所以用金屬可以制造好的烹飪鍋和電

26、線。,Valence ['ve?l?ns] n. [化](化合)價, 原子價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.化合價，原子價：原子或原子團與其它原子結合的能力是由

27、它在與其它的原子結合時所丟失、增加或共享的電子的數(shù)目決定的。,It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal. No photons pass through. 因為這些價電子吸收到達金屬的光子，所以透過金屬不可能看得見。沒有光子能通過金屬

28、。Alloys are compounds consisting of more than one metal. Adding other metals can affect the density, strength, fracture toughness, plastic deformation, electrical conductivity and environmental degradation. 合金是由一種以上金屬組

29、成的混合物。加一些其它金屬能影響密度、強度、斷裂韌性、塑性變形、導電性以及環(huán)境侵蝕。,For example, adding a small amount of iron to aluminum will make it stronger. Also, adding some chromium to steel will slow the rusting process, but will make it more brittle.

30、 例如，往鋁里加少量鐵可使其更強。同樣，在鋼里加一些鉻能減緩它的生銹過程，但也將使它更脆。,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.Se

31、e table at subatomic particle 光子，光量子：電磁能的量子，一般認為是有零質量、無電荷和不定長壽命的離散性粒子參見 subatomic particleA unit of retinal illumination, equal to the amount of light that reaches the retina through 1 square millimeter of pupil area f

32、rom a surface having a brightness of 1 candela per square meter.光度：視網膜亮度單位，相當于每平方米有一燭光亮度的表面，通過一平方毫米的瞳孔區(qū)域，到達視網膜的光線數(shù)量,Ceramics and Glasses陶瓷和玻璃,A ceramic is often broadly defined as any inorganic nonmetallic material．By

33、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義為無機的非金屬材料。照此定義，陶瓷材料也應包括玻璃；然而許多材料科學家添加了“陶瓷”必須同時是

34、晶體物組成的約定。A glass is an inorganic nonmetallic material that does not have a crystalline structure. Such materials are said to be amorphous. 玻璃是沒有晶體狀結構的無機非金屬材料。這種材料被稱為非結晶質材料。,Properties of Ceramics and Glasses陶瓷和玻璃的特

35、性,Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance. 高熔點、低密度、高強度、高剛度、高硬度、高耐磨性和抗腐蝕性是陶瓷和玻

36、璃的一些有用特性。,Stipulation n. 約定, 約束, 契約 The act of stipulating.制定：制定的行為Something stipulated, especially a term or condition in an agreement.條款：規(guī)定的東西，尤指約定中的條款或條件Amorphous adj. 無定形的, 無組織的Lacking distinct crystalline

37、structure.非結晶質的：沒有明確結晶結構的,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 cera

38、mics are superconductors at very low temperatures. Ceramics and glasses have one major drawback: they are brittle. 許多陶瓷都是電和熱的良絕緣體。某些陶瓷還具有一些特殊性能：有些是磁性材料，有些是壓電材料，還有些特殊陶瓷在極低溫度下是超導體。陶瓷和玻璃都有一個主要的缺點：它們容易破碎。,Insulator n.

39、 絕緣體, 絕熱器A material that insulates, especially a nonconductor of sound, heat, or electricity. 絕緣體：絕緣材料，特別是聲、熱、電的非導體A device that insulates. 絕緣裝置,Ceramics are not typically formed from the melt. This is because most cer

40、amics 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。因為大多數(shù)陶瓷在從液態(tài)冷卻時將會完全破碎(即形成粉末)。,Piezoelectric [物]壓電的,Hence, all the simple and efficient manufacturing techniques use

41、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

42、璃生產的簡單有效的—諸如澆鑄和吹制這些涉及熔化的技術都不能用于由晶體物組成的陶瓷的生產。作為替代，一般采用“燒結”或“焙燒”工藝。,Sintering v. 燒結 n. 燒結, 熱壓,In sintering, ceramic powders are processed into compacted shapes and then heated to temperatures just below the melting p

43、oint. At such temperatures, the powders react internally to remove porosity and fully dense articles can be obtained. 在燒結過程中，陶瓷粉末先擠壓成型然后加熱到略低于熔點溫度。在這樣的溫度下，粉末內部起反應去除孔隙并得到十分致密的物品。,Porosity [p?:?r?s?ti] n. 多孔性, 有孔性The

44、state or property of being porous.有孔性，多孔性：有孔或多孔的狀態(tài)或特性A structure or part that is porous. 多孔部分或多孔結構The ratio of the volume of all the pores in a material to the volume of the whole.孔隙率：一材料中孔隙的總體積與整個材料的體積之間的比率,An optica

45、l fiber contains three layers: a core made of highly 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 gl

46、ass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage. 光導纖維有三層：核心由高折射指數(shù)高純光傳輸玻璃制成，中間層為低折射指數(shù)玻璃，是保護核心玻璃表面不被擦傷和完整性不被破壞的所謂覆層，外層是聚合物護套，用于保護光導纖維不受損。,refractive inde

47、x 折射率Cladding n. 覆層,金山詞霸翻譯結果：光導纖維有三層：由具有高折射率的光指數(shù)高純玻璃芯，中間層的玻璃具有較低的折射率稱為保護從劃痕和其它表面缺陷核心玻璃包層，和聚合物護套保護光纖免受損害。,In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a

48、small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light. 為了使核心玻璃有比覆層大的折射指數(shù)，在其中摻入微小的、可控數(shù)量的能減緩光速而不會吸收光線的雜質或攙雜劑。,Dopant A substance, such as boron, added i

49、n small amounts to a pure semiconductor material to alter its conductive properties for use in transistors and diodes.摻雜質，摻質劑：加入純半導體材料中的少量硼等物質，用于晶體管和二極管中以改變半導體的導電率,Because the refractive index of the core glass is great

50、er than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critic

51、al angle. 由于核心玻璃的折射指數(shù)比覆層大，只要在全內反射過程中光線照射核心/覆層分界面的角度比臨界角大，在核心玻璃中傳送的光線將仍保留在核心玻璃中。,The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with l

52、ittle loss of intensity. 全內反射現(xiàn)象與核心玻璃的高純度一樣，使光線幾乎無強度損耗傳遞長距離成為可能。,Composites 復合材料,Composites are formed from two or more types of materials. Examples include polymer/ceramic and metal/ceramic composites. Composites a

53、re used because overall properties of the composites are superior to those of the individual components. 復合材料由兩種或更多材料構成。例子有聚合物/陶瓷和金屬/陶瓷復合材料。之所以使用復合材料是因為其全面性能優(yōu)于組成部分單獨的性能。,For example: polymer/ceramic composites have

54、a greater modulus than the polymer component, but aren’t as brittle as ceramics.Two types of composites are: fiber-reinforced composites and particle-reinforced composites.例如：聚合物/陶瓷復合材料具有比聚合物成分更大的模量，但又不像陶瓷那樣易碎。 復合材

55、料有兩種：纖維加強型復合材料和微粒加強型復合材料。,Fiber-reinforced Composites纖維加強型復合材料Reinforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers. Fibers increase th

56、e modulus of the matrix material. 加強纖維可以是金屬、陶瓷、玻璃或是已變成石墨的被稱為碳纖維的聚合物。纖維能加強基材的模量。,Matrix n. ①(生物形成生長的)母體, 母體組織;【解】子宮 ②發(fā)源地, 策源地 ③【生】細胞間質, 基質 ④【礦】母巖, 雜礦石, 基巖;【地質】脈石, 填質; (巖石中化石等的)痕印 ⑤【冶】(合金的)基體 ⑥【刷】紙型, 字模 ⑦唱片模子 ⑧【數(shù)】陣,

57、矩陣, 真值表, 母式;【無】矩陣變換電路; 【語】主句、獨立句,The strong covalent bonds along the fiber’s length give them a very high modulus in this direction because to break or extend the fiber the bonds must also be broken or moved. 沿著纖維長度有

58、很強結合力的共價結合在這個方向上給予復合材料很高的模量，因為要損壞或拉伸纖維就必須破壞或移除這種結合。Fibers are difficult to process into composites, making fiber-reinforced composites relatively expensive. 把纖維放入復合材料較困難，這使得制造纖維加強型復合材料相對昂貴。,Covalent adj. [化]共有原子價

59、的, 共價的covalent bond 共價鍵Thermoset n. 熱固樹脂,熱固塑料 adj. 熱固的Thermoplastic adj. 熱塑性的 n. 熱塑性塑料Becoming soft when heated and hard when cooled.熱塑的：加熱時變軟冷卻時變硬的,Fiber-reinforced composites are used in some of the most adv

60、anced, and therefore most expensive sports equipment, such as a time-trial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix. 纖維加強型復合材料用于某些最先進也是最昂貴的運動設備，例如計時賽競賽用自行車骨架就是用含碳纖維的熱固塑料基材制成

61、的。Body parts of race cars and some automobiles are composites made of glass fibers (or fiberglass) in a thermoset matrix. 競賽用汽車和某些機動車的車體部件是由含玻璃纖維(或玻璃絲)的熱固塑料基材制成的。,Fibers have a very high modulus along their axis, b

62、ut have a low modulus perpendicular to their axis. Fiber composite manufacturers often rotate layers of fibers to avoid directional variations in the modulus. 纖維在沿著其軸向有很高的模量，但垂直于其軸向的模量卻較低。纖維復合材料的制造者往往旋轉纖維層以防模量產生方向變化

63、。,Particle-reinforced composites 微粒加強型復合材料Particles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous materials, including polymer

64、s and carbon black. 用于加強的微粒包含了陶瓷和玻璃之類的礦物微粒，鋁之類的金屬微粒以及包括聚合物和碳黑的非結晶質微粒。,Particles are used to increase the modulus of the matrix, to decrease the permeability of the matrix, to decrease the ductility of the matrix. An

65、 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、減少基材的滲透性和延展性。微粒加強型復合材料的一個例子是汽車輪胎，它就是在聚異丁烯人造橡膠聚合物基材中加入了

66、碳黑微粒。,Polyisobutylene [p?l?'a?s??'bju:t?li:n] n. [化]聚異丁烯Elastomeric [??læst?'mer?k] adj. 彈性體的, 人造橡膠的,Polymers 聚合材料,A polymer has a repeating structure, usually based on a carbon backbone. The repea

67、ting structure results in large chainlike molecules. Polymers are useful because they are lightweight, corrosion resistant, easy to process at low temperatures and generally inexpensive. 聚合物具有一般是基于碳鏈的重復結構。這種重復結構

68、產生鏈狀大分子。由于重量輕、耐腐蝕、容易在較低溫度下加工并且通常較便宜，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. The mechanical properties o

69、f 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)、軟化及熔化點、結晶度和結構。聚合材料的機械性能一般表現(xiàn)為低強度和高韌性。它們的強度通?？刹捎眉訌姀秃辖Y構來改