金属材料专业英语简单介绍优秀PPT.ppt
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1、金属材料专业英语简单介绍1第一页,本课件共有46页We should graspWhat is a metal?What is an alloy?What are the differences between their properities?Explain solid solution and intermetallic compound.2第二页,本课件共有46页New Words&Expressions from Part1roamrumgraphitegrfaitmalleablemliblductiledktailsolublesljublchromiumkrumjmtransi
2、tiontrnzin shellelv.漫游,闲逛,徜徉漫游,闲逛,徜徉;n.漫步,漫游,徘徊漫步,漫游,徘徊n.石墨石墨a.有伸延性的,可锻的有伸延性的,可锻的a.易延展的,柔软的易延展的,柔软的 a.可溶解的,可溶的可溶解的,可溶的 n.铬铬n.转换,跃迁,过渡转换,跃迁,过渡n.壳,外壳壳,外壳3第三页,本课件共有46页Translation InThe outmost layer of electrons 最外层电子最外层电子nFree election gas 自由电子气自由电子气 nElectrical conductivity 电导率,电导性电导率,电导性nPlain-carbo
3、n steel 普通碳素钢普通碳素钢 nSolid solution 固溶体,固溶液,固体溶液固溶体,固溶液,固体溶液4第四页,本课件共有46页Translation IInIntermetallic compound 金属互化物金属互化物nMetallic material 金属材料金属材料 nStrainless steel 不锈钢不锈钢nSolute 溶质溶质 nSolvent 溶剂溶剂Periodic table 元素周期表元素周期表Electronegativity 电负性电负性Transition metal 过渡金属过渡金属 Crystal structure 晶体结构晶体结构5
4、第五页,本课件共有46页What is a Metal?Q:What is a Metal?A:Metal is consisted of positive centers(or ions)sitting in a“gas”of free-electros.It tends to be good electrical conductors.6第六页,本课件共有46页What is an Alloy?Consist of a mixture of a pure and one or more other elements.由两种或两种以上的金属或金属与非金属由两种或两种以上的金属或金属与非金属经
5、一定方法所合成的具有金属特性的物质。经一定方法所合成的具有金属特性的物质。7第七页,本课件共有46页Its some properties:less malleable and ductile than pure metals and tend to have lower to melting points.合金的一些性质:延展性较差,低熔点。合金的一些性质:延展性较差,低熔点。8第八页,本课件共有46页Something else.1、合金根据组成元素的数目,可分为二元、合金根据组成元素的数目,可分为二元合金、三元合金和多元合金。合金、三元合金和多元合金。2、根据结构的不同,合金主要类型是:
6、、根据结构的不同,合金主要类型是:(1)混合物合金:当液态合金凝固时,构成合混合物合金:当液态合金凝固时,构成合金的各组分分别结晶而成的合金,如焊锡;金的各组分分别结晶而成的合金,如焊锡;(2)固熔体合金当液态合金凝固时形成固溶体固熔体合金当液态合金凝固时形成固溶体的合金,如金银合金;的合金,如金银合金;(3)金属互化物合金:各组分相互形成化合物金属互化物合金:各组分相互形成化合物的合金,如铜、锌组成的黄铜。的合金,如铜、锌组成的黄铜。9第九页,本课件共有46页3、合金的一些性质:、合金的一些性质:(1)多数合金熔点低于其组分中任一种组成多数合金熔点低于其组分中任一种组成金属的熔点;金属的熔点
7、;(2)硬度比其组分中任一金属的硬度大;硬度比其组分中任一金属的硬度大;(3)合金的导电性和导热性低于任一组分金合金的导电性和导热性低于任一组分金属。利用合金的这一特性,可以制造高电属。利用合金的这一特性,可以制造高电阻和高热阻材料。还可制造有特殊性能的阻和高热阻材料。还可制造有特殊性能的材料。材料。(4)有的抗腐蚀能力强有的抗腐蚀能力强(如不锈钢如不锈钢)4、常见合金:球墨铸铁、锰钢、不锈钢、常见合金:球墨铸铁、锰钢、不锈钢、黄铜、青铜、白铜、焊锡、硬铝、黄铜、青铜、白铜、焊锡、硬铝、18K黄黄金、金、18K白金。白金。10第十页,本课件共有46页What is an Alloy?Q:Wha
8、t is an Alloy?A:An alloy consists of a mixture of a pure metal and one or more other elements which can be metals or non-metal.Q:What are the differences between their properties?A:Alloys are usually less malleable and ductile than pure metals and the tend to have lower melting points.11第十一页,本课件共有46
9、页Think about.Give examples to explain soild solution and intermetallic compound?12第十二页,本课件共有46页Solid SolutionsIn many cases,metals are quite soluble in other metals.For example,solid copper and soild nickel are fully soluble in each other.This type of perfect soild solubility is a side effect of hav
10、ing free electrons.Since the electrons are free to move,the exact number of valence electrons possessed by any given atom shouldnt matter.13第十三页,本课件共有46页So a“solid-solution”is that one metal serves as the solvent and the other as the other as the solute,althought in a case like copper and nickel whe
11、re these are mutually soluble at all compositions the terms solvent and solute can be a little misleading.14第十四页,本课件共有46页For example,the figure in the right is Au-Ag phase diagram,below fusiform area is solid solutions,15第十五页,本课件共有46页Intermetallic CompoundsNot all metals are soluble in other metals,
12、thus,produced another new phase called“intermetallic compounds”,such as nickel will dissolve some aluminum,so that at low aluminum contents a solid solution is produced.But if larger amounts of aluminum are added,then produce intermetallic compounds.16第十六页,本课件共有46页Some of these compounds have a very
13、 well defined composition,such as Ni3AlOthers have quite a wide range of composition,such as NiAl17第十七页,本课件共有46页Three types of circumstances of intermetallic compounds formingThe first circumstance:size differenence The second circumstance:a large differenence in electronegativity The third circumst
14、ance:certain ratios of the number of valence electrons to the number of atoms in a structure18第十八页,本课件共有46页Hume-Rothery RuleHume-Rothery Rule 1:Atomic Size Factor(the 15%)Rule.Extensive substitutional solid solution occurs only if the relative difference between the atomic diameters(radii)of the two
15、 species is less than 15%.If the difference 15%,the solubility is limited.Comparing the atomic radii of solids that form solid solutions,theempirical rule given by Hume-Rothery is given as:Mismatch=19第十九页,本课件共有46页nHume-Rothery Rule 2:Crystal Structure Rule:For appreciable solid solubility,the crysta
16、l structures of the two elements must be identical.Hume-Rothery Rule 3:Valency Rule:A metal will dissolve a metal of higher valency to a greater extent than one of lower valency.The solute and solvent atoms should typically have the same valence in order to achieve maximum solubility.Hume-Rothery Ru
17、le 4:The Electronegativity Rule:Electronegativity difference close to 0 gives maximum solubility.The more electropositive one element and the more electronegative the other,the greater is the likelihood that they will form an intermetallic compound instead of a substitutional solid solution.The solu
18、te and the solvent should lie relatively close in the electrochemical series.20第二十页,本课件共有46页休姆罗瑟里(休姆罗瑟里(HumeRothery)规律)规律(1)形成合金的元素原子半径之差超过形成合金的元素原子半径之差超过1415,则固溶,则固溶度极为有限;若尺寸差小于度极为有限;若尺寸差小于15,尺寸因素成为次要的影响尺寸因素成为次要的影响因素,固溶度由其他影响因素确定,这就是知名的因素,固溶度由其他影响因素确定,这就是知名的15规律。规律。(2)如果合金组元的负电性相差很大,固溶度就极小;如果合金组元的负
19、电性相差很大,固溶度就极小;(3)两元素的固溶度与它们的原子价有关,高价元素在低价两元素的固溶度与它们的原子价有关,高价元素在低价元素中的固溶度大于低价元素在高价元素中的固溶度;元素中的固溶度大于低价元素在高价元素中的固溶度;(4)BB族溶质元素在族溶质元素在B族溶剂元素中的固溶度都族溶剂元素中的固溶度都相同相同(e/a=1.36),与具体的元素种类无关;,与具体的元素种类无关;(5)两组元只有具有相同的晶体结构才能形成无限两组元只有具有相同的晶体结构才能形成无限(或连或连续续)固溶体。固溶体。21第二十一页,本课件共有46页 各式各样的合金各式各样的合金磁磁性性合合金金 镍铬合金烤瓷牙镍铬合
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