AskDefine | Define alloys

User Contributed Dictionary

English

Noun

alloys
  1. Plural of alloy

Verb

alloys
  1. third-person singular of alloy

Extensive Definition

An alloy is a solid solution or homogeneous mixture of two or more elements, at least one of which is a metal, which itself has metallic properties. It usually has different properties from those of its component elements.
Alloying one metal with others often enhances its properties. For instance, steel is stronger than iron, its primary element. The physical properties, such as density, reactivity, Young's modulus, and electrical and thermal conductivity, of an alloy may not differ greatly from those of its elements, but engineering properties, such as tensile strength and shear strength may be substantially different from those of the constituent materials. This is sometimes due to the sizes of the atoms in the alloy, since larger atoms exert a compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation. Alloys may exhibit marked differences in behavior even when small amounts of one element occur. For example, impurities in semi-conducting ferromagnetic alloys lead to different properties, as first predicted by White, Hogan, Suhl, Tian Abrie and Nakamura. Some alloys are made by melting and mixing two or more metals. Brass is an alloy made from copper and zinc. Bronze, used for statues, ornaments and church bells, is an alloy of tin and copper.
Unlike pure metals, most alloys do not have a single melting point. Instead, they have a melting range in which the material is a mixture of solid and liquid phases. The temperature at which melting begins is called the solidus and the temperature when melting is complete is called the liquidus. However, for most alloys there is a particular proportion of constituents which give them a single melting point or (rarely) two. This is called the alloy's eutectic mixture.

Classification

Alloys can be classified by the number of their constituents. An alloy with two components is called a binary alloy; one with three is a ternary alloy, and so forth. Alloys can be further classified as either substitution alloys or interstitial alloys, depending on their method of formation. In substitution alloys, the atoms of the components are approximately the same size and the various atoms are simply substituted for one another in the crystal structure. An example of a (binary) substitution alloy is brass, made up of copper and zinc. Interstitial alloys occur when the atoms of one component are substantially smaller than the other and the smaller atoms fit into the spaces (interstices) between the larger atoms.

Terminology

In practice, some alloys are used so predominantly with respect to their base metals that the name of the primary constituent is also used as the name of the alloy. For example, 14 carat gold is an alloy of gold with other elements. Similarly, the silver used in jewelry and the aluminium used as a structural building material are also alloys.
The term "alloy" is sometime used in everyday speech as a synonym for a particular alloy. For example, automobile wheels made of aluminium alloy are commonly referred to as simply "alloy wheels". The usage is obviously indefinite, since steels and most other metals in practical use are also alloys.

References

External links

alloys in Afrikaans: Legering
alloys in Arabic: سبيكة
alloys in Belarusian: Сплаў
alloys in Bosnian: Legura
alloys in Bulgarian: Сплав
alloys in Catalan: Aliatge
alloys in Czech: Slitina
alloys in Danish: Legering
alloys in German: Legierung
alloys in Estonian: Sulam
alloys in Modern Greek (1453-): Κράμα
alloys in Spanish: Aleación
alloys in Esperanto: Alojo
alloys in Persian: آلیاژ
alloys in French: Alliage
alloys in Scottish Gaelic: Coimheatailt
alloys in Galician: Aliaxe
alloys in Korean: 합금
alloys in Croatian: Legura
alloys in Ido: Aloyo
alloys in Indonesian: Aloy
alloys in Icelandic: Málmblanda
alloys in Italian: Lega (metallurgia)
alloys in Hebrew: סגסוגת
alloys in Swahili (macrolanguage): Aloi
alloys in Lithuanian: Lydinys
alloys in Macedonian: Легура
alloys in Malay (macrolanguage): Aloi
alloys in Mongolian: Хайлш
alloys in Dutch: Legering
alloys in Japanese: 合金
alloys in Norwegian: Legering
alloys in Norwegian Nynorsk: Legering
alloys in Narom: Alouai
alloys in Uighur: قېتىشماق
alloys in Polish: Stop metali
alloys in Portuguese: Liga metálica
alloys in Romanian: Aliaj
alloys in Russian: Сплав
alloys in Simple English: Alloy
alloys in Slovenian: Zlitina
alloys in Serbian: Легура
alloys in Finnish: Metalliseos
alloys in Swedish: Legering
alloys in Tamil: கலப்புலோகம்
alloys in Thai: โลหะผสม
alloys in Vietnamese: Hợp kim
alloys in Turkish: Alaşım
alloys in Ukrainian: Сплави
alloys in Yiddish: געמיש מעטאלען
alloys in Chinese: 合金
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