机械英语文章中英文对照

1、Ceramics and Glasses陶瓷和玻璃A ceramic is often broadly defined as any inorganic nonmetallic material By 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

2、多材料科学家添加了“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 GlassesSome of the useful properties of ceramics and glasses include high melting te

3、mperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance.陶瓷和玻璃的特性 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。Many ceramics are good electrical and thermal insulators. Someceramics have special properties: some ceramics are magnetic materials; some are pi

4、ezoelectric materials; and a few special ceramics are superconductors at very low temperatures. 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。Ceramics are not typically formed from the melt.

5、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 )。Hence, all the simple and efficientmanufacturing techniques used for glassproduction such as casting and blowing, which involve the molten state, ca

6、nnot 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。In sintering, ceramic powders are processed into compacted shapes and then heatedto temperatures just bel

7、ow 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物品。Anrefractiveoptical fiber contains three layers: a core made of highly pure glass witha high refractivein

8、dex for the light to travel, a middle layer of glass with a lowerindex known as the cladding which protects the core glass from scratches damage.and other surfaceimperfections,and an out polymer jacket to protect the fiber from光导纤维有三层：核心由高折射指数高纯光传输玻璃制成，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

9、护套， 用于 保护光导纤维不受损。In order for the core glass to 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

10、搀杂剂。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 core 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

11、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, 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 tw

12、o or more types of materials. Examples include polymer/ceramic and metal/ceramic composites. Composites are used because overall properties of the 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/

13、ceramic composites have 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 CompositesRe

14、inforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers. Fibers increase the modulus of the matrix material.纤维加强型复合材料 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。The strong covalent bonds along the fiber' s length giv

15、e them a very high modulusin 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

16、得制造纤维加强型复合材料相对昂贵。Fiber-reinforced composites are used in some of the most advanced, and therefore most expensive sports equipment, such as a 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

17、 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 rota

18、te 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 compositesParticles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous mate

19、rials, including polymers and carbon black.微粒加强型复合材料 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 modulus 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 aut

20、omobile 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 个例子是机动车胎，它就是在聚异丁烯人造橡胶聚合物基材中加入了碳黑微粒。? Polymers 聚合材料A polymer has a repeating structure, usually based on a carbon backbone.The repeating structure results in large cha

21、inlike 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 wei

22、ght), softening and melting points, crystallinity, and structure. The 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

23、通常可采用加强复合结构来改 善。Important Characteristics of PolymersSize. Single polymer molecules typically have molecular weights between10,000 and 1,000,000g/mol that can be more than 2,000 repeating units depending on the polymer structure! 聚合材料的重要特性尺寸：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

24、,000 个重复单元还多。The mechanical properties of a polymer are significantly affected 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. The softening point (glass transition temperature) and the melting point of a p

25、olymer will determine which it will be suitable for applications. These temperatures usually determine the upper limit for which a polymer can be used.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 industriallyimportant polymers have glass transitiontemperatures near th

26、e boiling point of water (100 °C, 212 T ), and they are most useful for room temperature applications. Somespecially engineered polymers can withstand temperatures as high as 300 C (572 T ).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 C , 212T ) ，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 300C(572T )的温度。Crystallinity.Po

27、lymers can be crystalline or amorphous, but they usuallyhave a combination of crystalline and amorphous structures (semi-crystalline).结晶度：聚合物可以是晶体状的或非结晶质的，但它们通常是晶体状和非结晶质结 构的结合物 ( 半晶体 ) 。Interchain interactions. The polymer chains can be free to slide past one another (thermo-plastic) or they can be

28、connected to each other with crosslinks (thermoset or elastomer). Thermo-plastics can be reformed and recycled, while thermosets and elastomers are not reworkable.原子链间的相互作用：聚合物的原子链可以自由地彼此滑动( 热可塑性 ) 或通过交键互相连接 (热固性或弹性 ) 。热可塑性材料可以重新形成和循环使用，而热固性与弹性材料则是不能再使用的。Intrachain structure. The chemical structure

29、of the chains also has a tremendous effect on the properties. Depending on the structure the polymer may be hydrophilic or hydrophobic (likes or hates water), stiff or flexible, crystalline or amorphous, reactive or unreactive.链内结构：原子链的化学结构对性能也有很大影响。根据各自的结构不同，聚合物 可以是亲水的或憎水的 ( 喜欢或讨厌水 ) 、硬的或软的、 晶体状的或非

30、结晶质的、 易起反应的 或不易起反应的。第二单元The understanding of heat treatment is embraced by the broader study of metallurgy. Metallurgy is the physics, chemistry, and engineering related to metals from ore extraction to the final product.对热处理的理解包含于对冶金学较广泛的研究。冶金学是物理学、化学和涉及金属 从矿石提炼到最后产物的工程学。Heat treatment is the opera

31、tion of heating and cooling a metal in its solid state to change its physical properties. According to the procedure used, steel can be hardened to resist cutting action and abrasion, or it can be softened to permit machining.热处理是将金属在固态加热和冷却以改变其物理性能的操作。 按所采用的步骤， 钢可以通过 硬化来抵抗切削和磨损，也可以通过软化来允许机加工。With t

32、he proper heat treatment internal stresses may be removed, grain size reduced, toughness increased, or a hard surface produced on a ductile interior. The analysis of the steel must be known because small percentages of certain elements, notably carbon, greatly affect the physical properties.使用合适的热处理

33、可以去除内应力、细化晶粒、增加韧性或在柔软材料上覆盖坚硬的表面。 因为某些元素 （尤其是碳 ） 的微小百分比极大地影响物理性能，所以必须知道对钢的分析。Alloy steel owe their properties to the presence of one or more elements other than carbon, namely nickel, chromium, manganese, molybdenum, tungsten, silicon, vanadium, and copper. Because of their improved physical properti

34、es they are used commercially in many ways not possible with carbon steels.合金钢的性质取决于其所含有的除碳以外的一种或多种元素，如镍、铬、锰、钼、 钨、硅、钒和铜。由于合金钢改善的物理性能，它们被大量使用在许多碳钢不适用的地方。The following discussion applies principally to the heat treatment of ordinary commercial steels known as plain carbon steels. With this process the

35、 rate of cooling is the controlling factor, rapid cooling from above the critical range results in hard structure, whereas very slow cooling produces the opposite effect. 下列讨论主要针对被称为普通碳钢的工业用钢而言。 热处理时冷却速率是控制要素， 从高于临界温度快速冷却导致坚硬的组织结构，而缓慢冷却则产生相反效果。? A Simplified Iron-carbon Diagram 简化铁碳状态图If we focus on

36、ly on the materials normally known as steels, a simplified diagram is often used.如果只把注意力集中于一般所说的钢上，经常要用到简化铁碳状态图。Those portions of the iron-carbon diagram near the delta region and those above 2% carbon content are of little importance to the engineer and are deleted. A simplified diagram, such as th

37、e one in Fig.2.1, focuses on the eutectoid region and is quite useful in understanding the properties and processing of steel. 铁碳状态图中靠近三角区和含碳量高于2%的那些部分对工程师而言不重要，因此将它们删除。如图 2.1 所示的简化铁碳状态图将焦点集中在共析区， 这对理解钢的性能和处理是十分 有用的。The key transition described in this diagram is the decomposition of single-phase au

38、stenite（ 丫 ） to the two-phase ferrite plus carbide structure astemperature drops.在此图中描述的关键转变是单相奥氏体(丫)随着温度下降分解成两相铁素体加渗碳体组织结构。Control of this reaction, which arises due to the drastically different carbon solubility of austenite and ferrite, enables a wide range of properties to be achieved through he

39、at treatment. 控制这一由于奥氏体和铁素体的碳溶解性完全不同而产生的反应， 使得通过热处理能获得很 大范围的特性。To begin to understand these processes, consider a steel of the eutectoid composition, 0.77% carbon, being slow cooled along line x-x' in Fig.2.1. At the upper temperatures, only austenite is present, the 0.77% carbon beingdissolved

40、in solid solution with the iron. When the steel cools to 727°C (1341 °F ),several changes occur simultaneously.为了理解这些过程，考虑含碳量为 0.77%的共析钢，沿着图 2.1 的 x-x '线慢慢冷却。 在较高温度时，只存在奥氏体， 0.77%的碳溶解在铁里形成固溶体。 当钢冷却到 727C (1341 F) 时，将同时发生若干变化。The iron wantsto change from the FCC austenite structureto th

41、e BCC ferritestructure, but the ferrite can only contain 0.02% carbon in solid solution.铁需要从面心立方体奥氏体结构转变为体心立方体铁素体结构，但是铁素体只能容纳固溶体状态的 0.02%的碳。with composition t ferriteThe rejected carbon forms the carbon-rich cementite intermetallicFe3C. In essence, the net reaction at the eutectoid is austenite 0.77

42、%C 0.02%C+cementite 6.67%C.被析出的碳与金属化合物 Fe3C 形成富碳的渗碳体。本质上，共析体的基本反应是奥氏体 0.77%的碳t铁素体 0.02%的碳+渗碳体6.67%的碳。Since this chemical separation of the carbon component occurs entirely in the solid state, the resulting structure is a fine mechanical mixture of ferrite and cementite. Specimens prepared by polishi

43、ng and etching in a weak solution of nitric acid and alcohol reveal the lamellar structure of alternating plates that forms on slow cooling.由于这种碳成分的化学分离完全发生在固态中，产生的组织结构是一种细致的铁素 体与渗碳体的机械混合物。 通过打磨并在弱硝酸酒精溶液中蚀刻制备的样本显示出由缓慢冷 却形成的交互层状的薄片结构。This structure is composed of two distinct phases, but has its own

44、set of characteristic properties and goes by the name pearlite, because of its resemblance to mother- of- pearl at low magnification.这种结构由两种截然不同的状态组成， 但它本身具有一系列特性， 且因与低倍数放大时的珠 母层有类同之处而被称为珠光体。Steels having less than the eutectoid amount of carbon (less than 0.77%) are known as hypo-eutectoid steels.

45、Consider now the transformation of such a material represented by cooling along line y-y' in Fig.2.1.含碳量少于共析体 (低于 0.77%)的钢称为亚共析钢。现在来看这种材料沿着图 2.1 中 y-y '线冷却的转变情况。At high temperatures, the material is entirely austenite, but upon cooling entersa region where the stable phases are ferrite and a

46、ustenite. Tie-line and level-law calculations show that low-carbon ferrite nucleates and grows, leaving the remaining austenite richer in carbon.在较高温度时， 这种材料全部是奥氏体， 但随着冷却就进入到铁素体和奥氏体稳定状态的区 域。由截线及杠杆定律分析可知，低碳铁素体成核并长大，剩下含碳量高的奥氏体。At 727 °C (1341 °F), the austenite is of eutectoid composition (0

47、.77% carbon) and further cooling transforms the remaining austenite to pearlite. The resulting structure is a mixture of primary or pro-eutectoid ferrite (ferrite that formed above the eutectoid reaction) and regions of pearlite.在 727C (1341 F )时，奥氏体为共析组成 (含碳量 0.77%)，再冷却剩余的奥氏体就转化为珠 光体。作为结果的组织结构是初步的共

48、析铁素体 ( 在共析反应前的铁素体 ) 和部分珠光体的混 合物。Hypereutectoid steels are steels that contain greater than the eutectoid amount of carbon. When such steel cools, as shown in z-z' of Fig.2.1 the processis similar to the hypo-eutectoid case, except that the primary or pro-eutectoid phase is now cementite instead

49、of ferrite.过共析钢是含碳量大于共析量的钢。当这种钢冷却时，就像图 2.1 的 z-z '线所示， 除了初步的共析状态用渗碳体取代铁素体外，其余类似亚共析钢的情况。As the carbon-rich phase forms, the remaining austenite decreases in carbon content, reaching the eutectoid composition at 727C (1341 F ). As before, any remainingaustenite transforms to pearlite upon slow coo

50、ling through this temperature.随着富碳部分的形成，剩余奥氏体含碳量减少，在 727C(1341F )时达到共析组织。就像以 前说的一样，当缓慢冷却到这温度时所有剩余奥氏体转化为珠光体。It should be remembered that the transitions that have been described by the phase diagrams are for equilibrium conditions, which can be approximated by slow cooling. With slow heating, these t

51、ransitions occur in the reverse manner.应该记住由状态图描述的这种转化只适合于通过缓慢冷却的近似平衡条件。如果缓 慢加热，则以相反的方式发生这种转化。However, when alloys are cooled rapidly, entirely different results may be obtained, because sufficient time is not provided for the normal phase reactions to occur, in such cases, the phase diagram is no l

52、onger a useful tool for engineering analysis.然而， 当快速冷却合金时， 可能得到完全不同的结果。 因为没有足够的时间让正常的状态反 应发生，在这种情况下对工程分析而言状态图不再是有用的工具。? Hardening 淬火Hardening is the process of heating a piece of steel to a temperature within or above its critical range and then cooling it rapidly.淬火就是把钢件加热到或超过它的临界温度范围，然后使其快速冷却的过程。I

53、f the carbon content of the steel is known, the proper temperature to which the steel should be heated may be obtained byreference to the iron-iron carbide phasediagram. However, if the composition of the steel is unknown, a little preliminary experimentation may be necessary to determine the range.

54、如果钢的含碳量已知， 钢件合适的加热温度可参考铁碳合金状态图得到。 然而当钢的成分不 知道时，则需做一些预备试验来确定其温度范围。A good procedure to follow is to heat-quench a number of small specimens of the steel at various temperatures and observe the result, either by hardness testing or by microscopic examination. When the correct temperature is obtained, t

55、here will be a marked change in hardness and other properties. 要遵循的合适步骤是将这种钢的一些小试件加热到不同的温度后淬火， 再通过硬度试验或显 微镜检查观测结果。一旦获得正确的温度，硬度和其它性能都将有明显的变化。In any heat-treating operation the rate of heating is important. Heat flows from the exterior to the interior of steel at a definite rate. If the steel is heate

56、d too fast, the outside becomes hotter than the interior and uniform structure cannot be obtained.在任何热处理作业中，加热的速率都是重要的。热量以一定的速率从钢的外部传导 到内部。如果钢被加热得太快，其外部比内部热就不能得到均匀的组织结构。If a piece is irregular in shape, a slow rate is all the more essential to eliminate warping and cracking. The heavier the section,

57、 the longer must bethe heating timeto achieve uniform results.如果工件形状不规则， 为了消除翘曲和开裂最根本的是加热速率要缓慢。 截面越厚， 加热的 时间就要越长才能达到均匀的结果。Even after the correct temperature has been reached, the piece should be held at that temperature fora sufficient period of time to permit its thickestsection toattain a uniform

58、temperature.即使加热到正确的温度后，工件也应在此温度下保持足够时间以让其最厚截面达到相同温 度。The hardness obtained from a given treatment depends on the quenching rate, the carbon content, and the work size. In alloy steels the kind and amount of alloying element influences only the hardenability (the ability of the workpiece to be harde

59、ned to depths) of the steel and does not affect the hardness except in unhardened or partially hardened steels.通过给定的热处理所得到的硬度取决于淬火速率、含碳量和工件尺寸。除了非淬硬 钢或部分淬硬钢外，合金钢中合金元素的种类及含量仅影响钢的淬透性( 工件被硬化到深层的能力 ) 而不影响硬度。Steel with low carbon content will not respond appreciably to hardening treatment. As the carbon content in steel