机械设计制造及自动化专业英语翻译文档格式.docx

1、?电子associated with these atoms. In a more practical way, haweven a metal can be defined as an elemenl which has a particular package of properties在人类社会的发|R中:金属的 应用起着关准性的作用中网成 物處的大约100种基事元素 中，大约有一半为金属中金属 和非金属之间的区别不是特别 明显勺最葛本的定义集中在元 景原子间存在的连接形式和与 这些摞子相关联的电子的某些 特性刖黙而,在实际应用中f 可JUWA有某些蒔性竄合金18 定义为某种元素口Met

2、als are Giystal line adj 晶协的wtien in the solid state and, with 1w exceptions极少例外（日 g mercury）, are solid at ambientt周固師撓的Jt日mpEr日nines. They are good conductora rf heat ard electricity and Bre opaque不透明的to I ight. They us ually iave a comparatively high density. Many metals ar ducti l&柔软 的；易延展的Mh凯 i

3、s, ttieir shape can be-changed perrrianentlyjKA 地.故期不变 ife by th葩 appilicatiGn of a force without breaking. The forces required to cause this deformation and ttiase required to break or fracture a metal are connpanatively high, althougli, the fracture forces is net nearlyf =far fromFrnuch less than

4、as high as would be expected from simple consideration ol the forces required to tear apart tlie atoms of the nnetal.在篇加下最 固愆的它们是热籾电的艮导 体不透光。它们往往黒有较 高的密度口许赛金屋具有延農 性，也就是说在不械破坏的 情况下它们的刑状在蚪力的柞 用下可歐岌生变化。引起永久 变册所霜的力和最皱使金属断 製所离的力相当大,愿萱发生 断裂所需的力远没有像所预期 的SB开金易凜子所需的力那幺 大.Ore of ttie more eignifitam of th&e&

5、eharacteristics from our point of vi ew is that of crys ta llinityfcrys tall ini ty jknstlinVfi. A crystalline solid is one in which the constituent atoms are locaied in a regular th rve-dirnensiQinal srray as if they w&re located at the Gorrers of the squares of a thre-dimensionall chess boa rdn. 棋

6、盘The spacing of tfie atoms in the array is of the same order the size of the atoms5 tbie actual spacing being a characteristic of the particular metaL The directions of the axes of the array define the orientation of the crystal ir spacr The metals commonly从我柏的观点来看隹所有的 特性中结晶性是最更要的白结 晶体是这祥一种结构,组成它 的杲

7、子定俚在规则的三维排列 中，仿佛位于三维棋盘的方格 的角上口原子间距随着崩子大 小呈规律性变化,原子间距是 金盛的一种待性。三娃排列的 轴竣决足了晶悴在空间中的方 向在H程实腹中应用的金属 由大量的晶休组成这些晶悴used in engineering practice are composed of a large number nf such crystals, called grain戲晶转,In the most general 匚ase下the crysials of the various grains are randcmly oriented in sr）a匚日.The gra

8、ins are everywhere in intimate contact with one another and joined togettier on 且n atomic scale. The region at which they join is known as a grain boundary An absolutely pure metal i s 也就显one composed of nly one type of atom） has never been produced. Engineers would not be particularly interested in

9、 such a metal even if it were to be prod uced. because it would be soft and waak The m-eials used commercelly in suitably 不可避免地contain mall amuunts of one or more foreign elemants either inetallicinGallic mrtTlik, me-adj.金居的,Mor nonmetallic. These foreign elements may be detrimental害的,they may be be

10、n&ficiahl, or they may liav no influence at all on s particular prupert/. If disadvantageouSj ttia foreign elerneirts tand to be known as impurities. If advantageousr they tend to be known as alloying elementsf元素Alloying elements are commonly add&d d&lib&ratelyl%地,蓄蕙地in substaniialadj 大 的；实JS的；内容充实的

11、substantial evidence （质） 悴证据|冥质性证据|头质证JE substantial order: 仃单|大订单amounts in engineering material&. The result is known as an allayThe distinction between the descriptors m-etar1 and alloy is not Glear-cuL The term flm0tar may used to enwjmpass both a. rn merci ally pur metal and its alloys. Perhaps

12、 it wn be 闕id thqt the rnore deliberately an alloying addition has been made and tfi-e larger the amount of the addition, the more likely it is that the prodUGt will specifically be called an alloy. In any称之为晶粒中在犬务数情况卞， 晶粒在空同中星自由排列的卩 在原子范围内，晶粒之间梱互 接触章密结合口晶粒之间连接 区域破称为晶界口绝对纯净的金属从来也没荷被 生产出来iL即使地对郭净的 金属

13、可凤生产出来，工程师f 对它们也井不会特别感兴趣， 因为它杓很柔轶*脆弱.实际 应用中的金厲往往都包會着一 定数凤曲一种或舍和外来金屢 或菲金糅元素，還些外来元素 可僅最有害飽也可能是有益的 或者它们对某种特定的届性设 有誓响。如果屋有害的,SS 纵来元素雜认询是杂质。如果 是有益的,它们被认为星合金 元素。在工程材料中往往桩特 奪地加入一定敷量的合金无 乗。得到的辆质被叫楝合金金属利合金区别卒大勺金属这 带词可駄包桔工业用死金層和 它的合金。也许可规这样说， 合金元素越故意的被添加被 淨加的合金元素的凤越大那 么主产出来的产品越倾向于袪 称之再合金口干管怎样如果 想使一种金属或合金在使用中

14、表现出柚定一数的特性ttM 中添加何种化学成分，它的己 多大都庖该在控制范围之内。因此，当艱了解决定金属和合nt无论 JO何 芹管怎样i the chemical composition of a metal oran alloy must be known and oontr-olled within certain limits if GonsisteitSfcfe parfcrmanGe is to b& achieved in service Thus Ghamical composition has ! be taken into aGGOunt when developing an und-erstandingof the factors which determine the properties of metals and their alloys.金性贋的因茶吋,应充分考虑 它们的化学组咸。Of tiie 50 or so metallic eements, only 白 few are produced and used in large q