材料成型及控制工程专业英语-_1.MATERIALS_AND_THEIR_PROPERTIES

材料成型及控制工程 专业英语

2009 © Hisuntech Corp.

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

1.1 Metals and Non-metals

Words and terms

definite-确定的、明确的defect-缺陷 plastic deformation塑性变形 stress concentrator 应力集中点 self-strengthening自强化 the tip of a crock裂纹尖端- 1 -

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

Among numerous properties possessed by materials,their mechanical properties,in the majority of cases,are the most essential and therefore,they will be given much consideration in the book.

在一些主要应用场合，机械性能是材料的各种性能中最重要 的性能，因此，本书中将重点讨论。

consideration 考虑，需要考虑的事项，报酬- 2 -

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

All critical parts and elements,of which a high reliability (可靠性)is required,are made of metals, rather than of glass,plastics or stone.

由于各种关键零部件的可靠性要求高，均用金属而不是玻璃、 塑料或石头制造。

is required 翻译时将英文中的被动语态，改译为汉语中的主 动语态。 rather than 而不是- 3 -

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

As has been given in Sec.1-1,metals are characterized by the metallic bond(金属键),where positive ions (正离子) occupy the sites of the crystal lattice (晶格)and are surrounded by electron gas(电子云) . 正如Sec1-1中所说，金属主要由金属键组成(其特征主要 ……)。金属键就是正离子占有晶格位置，周围包围着电子 云。

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CHAPTER 1 MATERIALS AND THEIR PROPERTIES

All non—metals have an ionic or a covalent bond(共价键), these types of bond are rigid and are due to electrostatic attraction of two ions of unlike charges. 非金属主要由离子键或者共价键组成。这些类型的化学键异 种电荷间的离子间的静电吸引连接在一起的。这种连接是刚 性的。

Bond n. 结合(物), 粘结(剂), 联结, 公债, 债券, 合同- 5 -

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

Because of the metallic bond,metals are capable of plastic deformation (塑性变形)and self-strengthening(加工硬化) upon plastic deformation. Therefore , if there is a defect(缺 陷) in a material or if the shape of an element is such that there are stress concentrators ,the stresses in these points may attain a great value and even cause cracking .

由于具有金属键，金属在(塑性)变形时具有塑性以及在塑性 变形基础上产生的加工硬化的象。因此，如果材料或者其某 部分中有缺陷，会导致应力集中，在这些点的应力会达到很 大甚至产生裂纹。- 6 -

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

but since the plasticity of the material is high,the metal is deformed plastically in that point,say,at the

tip of a crack, undergoes strengthening, and the process of fracture comes to an arrest.Arrest-停止、扣留、制动、逮捕。Fracture-裂纹、断裂

但是由于材料的塑性好，金属可以在这些位置产生塑性变形， 即：裂纹尖端产生硬化，会推迟断裂过程的产生。

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CHAPTER 1 MATERIALS AND THEIR PROPERTIES

This does not occur in non-metals.They are uncapable of plastic deformation and self-strengthening. Therefore, fracture(断裂) will occur as soon as the stresses at the tip of a defect exceed a definite value.

这一现象则不会在非金属中出现。非金属不能进行塑性变形 和发生加工硬化现象。因此，一旦某处缺陷的应力超过某一 定值后，就会产生断裂。

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CHAPTER 1 MATERIALS AND THEIR PROPERTIES

These facts explain why metals are reliable structural materials and can not be excelled by non—metallic materials

这些现象可以解释为什么金属可以作为可靠的结构材料而非 金属却不能(的原因)。

“why……” is the object clause.

Excelled

胜过,超过,优于,超越- 9 -

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

1.2 Ferrous Alloysdeoxidafion脱氧hot-rolled steel热轧钢

magnesium [化]镁manganese〈化〉锰(元素符号为 Mn) phosphorus磷 sulphur 硫 impurity n.杂质, 混杂物, 不洁, 不 纯

beam线材State Standard国家标准 forging锻造 alloying element合金元素 harmful impurity有害杂质 welding焊接 stamping冲压

plain carbon steel普通碳钢bar棒材

sheet板材- 10 -

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

More than 90% by weight of the metallic materials used by human beings are ferrous alloys. This represents an immense family of engineering materials (工程材料)with a wide range of microstructures and related properties.

人类所用的金属材料中90%的都为铁合金。这则说明功能材 料种类繁多，其组织和性能也各种各样。

Note:the long sentence should be decomposed into clause ( short sentence).- 11 -

CHAPTER 1 MATERIALS AND THEIR PROPERTIES

The majority of engineering designs that require structural load support or power transmission involve ferrous alloys.

工程设计中主要要求铁合金能够承受结构载荷或进行能量传 输。

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CHAPTER 1 MATERIALS AND THEIR PROPERTIES

As a practical matter,these alloys fall into two broad categories based on the carbon in the alloy composition. Steel generally contains between 0.05 and 2.0 wt%carbon The cast irons generally contain between 2.0 and 4.5 wt% carbon. wt%——weight percent carbon—碳

实际应用时，根据(铁)合金中碳含量将其分为两大类：钢铁 一般含有0.05-2.0wt%的碳，铸铁一般含有2.0-4.5%wt的碳。

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CHAPTER 1 MATERIALS AND THEIR PROPERTIES

Within the steel category,we shall distinguish whether or not

a significant amount of alloying elements other than carbon is used.A composition of 5wt% total non-carbon (非 碳元素) additions will serve as all arbitrary boundary between low alloy and high alloy steels.

在钢的分类中，我们还需明确是否使用了大量的合金中非碳 合金元素。高合金钢和低合金钢的严格界限在于非碳合金元 素的含量是否超过了5%wt.

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CHAPTER 1 MATERIALS AND THEIR PROPERTIES

These alloy additions are chosen carefully because they invariably bring with them sharply increased materials costs.They are justified only by essential improvements in properties such as higher strength or improved corrosion resistance.

因为合金元素的加入会导致材料成本的明显上升，所以， 选择加入合金元素时需谨慎。只有加入合金元素能改善 材料性能，比如提高强度或改善抗腐蚀性时，合金的添 加才比较合理。 “they”in the second sentence refer to“these alloy additions”in the first sentence.- 15 -