物理分类编辑
合金的通性
各类型合金都有以下通性：
(1)多数合金熔点低于其组分中任一种组成金属的熔点；
(2)硬度一般比其组分中任一金属的硬度大；（特例：钠钾合金是液态的，用于原子反应堆里的导热剂）
(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。
(4)有的抗腐蚀能力强(如不锈钢)如在铁中掺入15%铬和9%镍得到一种耐腐蚀的不锈钢，适用于化学工业
根据合金中含量较大的主要金属的名称而分类称作某某合金,如铜含量高的为铜合金,其性能主要保持铜的性能。
合金类型
(1)混合物合金（共熔混合物），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、铋镉合金等；
(2)固熔体合金，当液态合金凝固时形成固溶体的合金，如金银合金等；
(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（β-黄铜、γ-黄铜和ε-黄铜）等。
合金的许多性能优于纯金属，故在应用材料中大多使用合金(参看铁合金、不锈钢)。
Physical Classification Editor
COMPANITY OF ALLOYS
All kinds of alloys have the following general properties:
(1) The melting point of most alloys is lower than that of anyof the constituent metals.
(2) Hardness is generally greater than that of any metal in itscomponent; (Special case: sodium-potassium alloy is liquid and usedas heat conducting agent in atomic reactor)
(3) The conductivity and thermal conductivity of the alloy arelower than that of any component metal. High resistance and highthermal resistance materials can be manufactured by using thischaracteristic of alloys. It can also produce materials withspecial properties.
(4) Some stainless steels with strong corrosion resistance (suchas stainless steel) can be obtained by adding 15% chromium and 9%nickel into iron, which is suitable for chemical industry.
According to the name of the major metal in the alloy, it isclassified as a certain alloy. For example, the copper alloy withhigh copper content maintains the properties of copper.
Alloy type
(1) Mixed alloys (eutectic mixtures). When liquid alloys aresolidified, alloys composed of various components of the alloys arecrystallized separately, such as solder tin, bismuth-cadmiumalloys, etc.
(2) Solid melt alloys, alloys that form solid solutions whenliquid alloys solidify, such as gold and silver alloys;
(3) Metal intermetallic alloys, alloys in which components formcompounds, such as brass (beta-brass, gamma-brass andepsilon-brass) consisting of copper and zinc.
Many properties of alloys are better than pure metals, so alloysare mostly used in application materials (see ferroalloys,stainless steel).
