材料科学与工程_专业英语_Unit_2_Classification_of_Materials译文..doc

Unit 2 Classification of Materials Solid materials have been conveniently grouped into three basic classifications: metals, ceramics, and polymers. This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another, although there are some intermediates. In addition, there are three other groups of important engineering materials—composites, semiconductors, and biomaterials. 译文：固体材料被便利的分为三个基本的类型：金属，陶瓷和聚合物。这个分类是首先基于化学组成和原子结构来分的，大多数材料落在明显的一个类别里面，尽管有许多中间品。除此之外， 有三类其他重要的工程材料－复合材料，半导体材料和生物材料。 Composites consist of combinations of two or more different materials, whereas semiconductors are utilized because of their unusual electrical characteristics; biomaterials are implanted into the human body. A brief explanation of the material types and representative characteristics is offered next. 译文：复合材料由两种或者两种以上不同的材料组成，然而半导体由于它们非同寻常的电学性质而得到使用；生物材料被移植进入人类的身体中。关于材料类型和他们特殊的特征的一个简单的解释将在后面给出。 METALS Metallic materials are normally combinations of metallic elements. They have large numbers of nonlocalized electrons; that is, these electrons are not bound to particular atoms. Many properties of metals are directly able to these electrons. be bound to 被约束于。。 be attribute to 归属于。。归因于。。 译文：金属材料通常由金属元素组成。它们有大量无规则运动的电子。也就是说，这些电子不是被约束于某个特定的原子。金属的许多性质直接归属这些不规则运动的电子。 Metals are extremely good conductors of electricity and heat and are not transparent to visible light; a polished metal surface has a lustrous appearance. Furthermore, metals are quite strong, yet deformable, which accounts for their extensive use in structural applications. 科技英语在讲述科学真理的时候通常用主动语态。如： Metals are extremely good conductors of electricity Deformable ？ 译文：金属是十分好的电和热的导体，它们对可见光不透明；一个抛光的金属表面有光辉的外表。除此之外，金属是十分硬的，也是可变形的，这个性质解释了它们广泛使用在结构方面的应用。 CERAMICS Ceramics are compounds between metallic and nonmetallic elements; they are most frequently oxides, nitrides, and carbides. The wide range of materials that falls within this classificati