机械工程英语Unit 1 Advanced Engineering Materials.docxVIP

Unit 1 Advanced Engineering Material先进的工程材料Type of materials材料的分类Materials may be grouped 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.材料的分类方式有好几种。科学家们通常是根据固体，液体，或者气体来区分的，他们有时候也是将材料分为有机物（可再生的）和无机物（不可再生的）。For industrial purpose，materials are divided into engineering materials or nonengineering materials. Engineering materials are those used in manufacture and become parts of products. Nonengineering materials are the chemicals, fuels, lubricants（润滑剂）, and other materials used in the manufacturing process, which do not become part of the product.从工业的角度来看，材料可以分为工程材料和非工程材料，工程材料是用于生产组成，它是零件的一部分。非工程材料是化工，燃料，润滑剂和其他用于生产的材料，它们不是零件的组成部分。Engineering materials may be further subdivided into：①Metals ②Ceramics（陶瓷）③Composite ④Polymers（高分子材料）, etc.工程材料可进一步细化为1、金属。2、陶瓷。3、复合材料。4、高分子材料等。⑥⑦⑧⑨⑩Metals and Metal Alloys金属和金属合金Metals are elements that generally have good electrical and thermal（热量的） conductivity. Many metals have high strength ,high stiffness, and have good ductility（延展性）. Some metals, such as iron, cobalt and nickel, are magnetic. At extremely low temperatures, some metals and intermetallic compounds become superconductors.金属一般有高的导电能力和热导率，许多金属有很好的强度，高的硬度和好的延展性。铁钴镍这些金属是有磁性的。在极低的温度下，有些金属和金属化合物变得超导。What is the difference between an alloy and a pure metal? 合金和纯金属间的区别是什么呢？Pure metals are elements which come from a particular area of the periodic table.纯金属在化学周期表的特别区域。 Example of pure metals include copper（铜） in electrical wires and aluminum in cooking foil and beverage（饮料） cans. 例如，纯金属包括铜电线和铝制的饮箔和饮料罐头盒。Alloys contain more than one metallic element.合金不止含有一种金属元素。 Their properties can be changed by changing the elements present in the alloy.目前，可以通过改变合金的组成元素而改变它的一些特性。 Example of metal alloys include stainless steel（不锈钢） which is an alloy of iron, nickel, and chromium（铬）; and gold jewelry which usually contains an alloy of gold and nickel.例如，不锈钢是一种铁合金，