科技英语4.1

不断地，连续地
尽管在两类材料中相对重要的可能还将一 直是金属材料，但非金属材料的重要性却在迅 速提高，并且由于新的非金属材料的不断涌现， 这种提高的趋势肯定还会保持下去。
In many cases, the selection between a metal and nonmetal is determined by a consideration of required properties. Where the required properties are available in both, total cost becomes the determining factor.
动力传输 碳（元素）
大多数要求结构承重或动力传输的工程 设计都采用了铁合金。在实际应用中，这些合 金根据碳在合金成分中的含量被划分为两大类。
制造业 极大的 必须，紧要
A number of nonmetallic materials have 种类 substantial importance in manufacturing. Consequently, it is imperative for the design engineer to have an understanding of their natures, properties, advantages, and limitations so he may know when and how they may be used advantageously in his designs. 许多非金属材料在制造业中也占据重要地位。 因此，对于设计工程师来说，必须了解它们的 种类、特性、优点和局限性，这样他才能指导 何时和怎样在设计中更好的使用它们。
常见的非金属材料诸如木材、砖块、混凝土、 玻璃、橡胶和塑料。这些材料的特性差异和大，但 他们整体上表现为不易延展、较脆、与金属相比密 度较小，没有导电性以及导热性较差。
Although it is likely that metals always will be the more important of the two groups, the relative importance of the nonmetallic group is increasing rapidly, and since new nonmetals are being created almost continuously, this trend is certain to continue.
巨大的 微观结构 相关的
在人类使用的金属材料中，重量占90%以上 的都是铁合金。这代表着一个具有各种各样微观 结构与相关特性的巨大工程材料家族。
大多数 承重
The majority of engineering designs that require structural load support or power transmission involve ferrous alloys. As a practical matter, these alloys fall into two broad categories based on the carbon in the alloy composition.
镁 合金 镍 钛 铅 锡 黄铜 锌 青铜
金属材料和非金属材料的划分也许是材料选择 中最常见的一种分类形以及这些金 属的合金，如钢铁、黄铜、青铜等。
导热性（系数）
光泽，光彩
They possess the metallic properties of luster, thermal conductivity, and electrical conductivity; are relatively ductile; and some have good magnetic properties.
决定因素
在许多场合中，金属材料或非金属材料的选 择取决于所要求的特性，如果两种材料都具备该 需求特性，那么总的成本将成为决定性因素。
铁合金
More than 90% by weight of the metallic materials used by human beings are ferrous alloys. This represents an immense family of engineering materials with a wide range of microstructures and related properties.
导电性（系数） 磁性 易延展的
它们拥有金属的一些特性诸如光泽、导热性、导 电性、延展性，而且其中的某些还有较好的磁性。
非金属 橡胶
砖块
混凝土
塑胶，塑料
The common nonmetals are wood, brick, concrete, glass, rubber, and plastics. Their properties vary widely, but they generally tend to be less ductile, weaker, and less dense than the metals, and they have no electrical conductivity and poor thermal conductivity.
小结
metallic:金属的； nonmetallic:非金属的； alloy:合金； thermal conductivity:导热性，导热系数； electrical conductivity:导电性，导热率； magnetic :磁性 ； ferrous:铁的，含铁的；ferrous alloy：铁合金； load support:承重； power transmission:动力传输； carbon:碳.
Materials and Heat Treatment 材料与热处理
4.1 Metallic and Nometallic Materials 4.2 Iron and Its Production 4.3 Heat Treatment of Steel
Materials and Heat Treatment
金属的
非金属的
铁
铝
分类
Perhaps the most common classification that is encountered in materials selection is whether the material is metallic or nonmetallic. The common metallic materials are such metals as iron, copper, aluminum, magnesium, nickel, titanium, lead, tin, and zinc and the alloys of these metals, such as steel, brass, and bronze.
材料与热处理
英语谚语一则
To err is human. 人非圣贤，孰能无过。 人非圣贤，孰能无过。
课前小知识
英语知识小点滴
元旦 New Year ' s Day 国际劳动妇女节 International Working women' s Day（Women ' s Day） （ ） 国际劳动节 International Labor Day (May. Day) 中国青年节 Chinese Youth Day
家具
Except in furniture manufacturing, where wood is of prime importance, these materials are plastics, elastomers and ceramics.
陶瓷 首要 橡胶
在木材占首要重要性的家具制造业中则 例外，其材料包括塑料、橡胶和陶瓷。