机械工程英语第二版--叶邦彦(机械工业出版社)--全本书翻译

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机械工程英语第二版--叶邦彦(机械工业出版社)--全本书翻译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∑学家常根据状态将材料分为：固体、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 nonengineering materials. Engineering materials are those used in manufacture and become parts of products.
就工业效用而言，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。
Nonengineering materials 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: ①Metal ②Ceramics ③Composite ④Polymers， etc.
工程材料还能进-步细分为：①金属材料②陶瓷材料③复合材料 ④聚合材料，等等。
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 temperatures， 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 in 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。