金属材料专业介绍(ppt 47页)

❖ (3)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。
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❖ 3、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 金属的熔点；
❖ (2)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 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 材料。
❖ 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 where these are mutually soluble at all compositions the terms solvent and solute can be a little misleading .
❖ 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.
❖ This type of perfect soild solubility is a side effect of having free electrons.Since the electrons are free to move ,the exact number of valence electrons possessed by 12
金属互化物
Metallic material 金属材料
Periodic table 元素周期表
Strainless steel 不锈钢
Electronegativity 电负性
Solute 溶质
Transition metal 过渡金属
Solvent 溶剂
Crystal structur
❖ 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.
❖ (4)有的抗腐蚀能力强(如不锈钢)
❖ 4、常见合金： 球墨铸铁、锰钢、不锈钢、
黄铜、青铜、白铜、焊锡、硬铝、18K黄
金、18K白金。
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What is an Alloy?
❖ Q: What 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.
最外层电子
Free election gas 自由电子气
Electrical conductivity 电导率，电导性
Plain-carbon steel 普通碳素钢
Solid solution
固溶体，固溶液，固体溶液
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IntermetallicTcroamnpsoulandtion II
We should grasp…
❖ What is a metal? ❖ What is an alloy? ❖ What are the differences between their
properities? ❖ Explain solid solution and intermetallic
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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 经一定方法所合成的具有金属特性的物质。
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❖ Its some properties: less malleable and ductile than pure metals and tend to have lower to melting points.
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Think about…..
❖ Give examples to explain soild solution and intermetallic compound?
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Solid Solutions
❖ In many cases ,metals are quite soluble in other metals .For example ,solid copper and soild nickel are fully soluble in each other .
▪ a.易延展的，柔软的
❖ soluble[‘sɔljubl]
▪ a.可溶解的，可溶的
❖ chromium[‘krəumjəm] ▪ n.铬
❖ transition[træn‘ziʒən ] ▪ n.转换，跃迁，过渡 2
❖ shell[ʃel]
▪ n.壳，外壳
The outmostTlaryaenr soflaelteioctnronIs
❖ 合金的一些性质：延展性较差，低熔点。
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Something else…..
❖ 1、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。
❖ 2、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 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 的合金，如金银合金；
compound.
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New Words & Expressions from
❖ roam[rəum]
Par▪t1v.漫游，闲逛，徜徉 ；
▪ n.漫步，漫游，徘徊
❖ graphite['græ fait]
▪ n.石墨
❖ malleable['mæliəbl] ▪ a.有伸延性的，可锻的
❖ ductile[‘dʌktail]