《unit1 先进工程材料》由会员分享，可在线阅读，更多相关《unit1 先进工程材料（53页珍藏版）》请在金锄头文库上搜索。
1、Professional English 北华大学机械学院 王开宝Unit 1Types 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、液
2、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 mater
3、ials 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
4、料 聚合材料，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 compoun
5、ds 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
6、的Metals and Metal 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 t
7、emperatures, some 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 i
8、n electrical wires 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 wh
9、ich 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
10、require a high mass-to- 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
11、are durable.某些金属合金，例如铝基合金，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? Density 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？密度定义为材料的质量与其体积之比。大多数 金属密度相对
12、较高，尤其是和聚合物相比较而言。 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 hi
13、gh densities often contain 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
14、于既需要金属特性又要求重量轻的场合 。提示：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： 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Fracture toughness can be described as a materials ability to avoid fracture, especially when a flaw is introduced. Metals can generally contain nicks and dents without weakening very much
15、, and are impact resistant. A football player counts on this when he trusts that his facemask wont shatter.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 deformation is the ability of bend or deform before breaking. As engineers, we usually design materia
16、ls 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 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,
