Alloy 1187 225045829 2008-07-11T17:00:28Z Vsmith 84417 /* See also */ link fix [[Image:Steel wire rope.png|thumb|[[Steel]] is a metal alloy whose major component is [[iron]], with [[carbon]] content between 0.02% and 1.7% by mass.]] {{otheruses4|the material|the specification language|Alloy (specification language)}} An '''alloy''' is a [[solid solution]] or homogeneous mixture of two or more [[chemical element|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 conductivity|electrical]] and [[thermal conductivity]], of an alloy may not differ greatly from those of its elements, but engineering properties, such as [[tensile strength]]<ref>Adelbert Phillo Mills, (1922) ''Materials of Construction: Their Manufacture and Properties'', John Wiley & sons, inc, 489 pages, originally published by the University of Wisconsin, Madison</ref> and [[shear strength]] may be substantially different from those of the constituent materials. This is sometimes due to the sizes of the [[atom]]s 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.<ref>[http://prola.aps.org/abstract/PR/v188/i2/p870_1 C. Michael Hogan, (1969) ''Density of States of an Insulating Ferromagnetic Alloy'' Phys. Rev. 188, 870 - 874, [Issue 2 – December 1969]</ref><ref>[http://prola.aps.org/abstract/PRA/v32/i4/p2530_1. X. Y. Zhang and H. Suhl (1985) Phys. Rev. A 32, 2530 - 2533 (1985) [Issue 4 – October 1985]</ref> 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 (chemistry)|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 (purity)|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. ==See also== {{Wiktionarypar|alloy}} * [[List of alloys]] * [[Intermetallics]] * [[Heat treatment]] * [[CALPHAD (method)]] ==References== {{reflist}} ==External links== * [http://www.uni-ulm.de/~hhoster/personal/surface_alloys.html Surface alloys] [[Category:Alloys|*]] [[Category:Metallurgy]] <!-- interwiki --> [[af:Legering]] [[ar:سبيكة]] [[be:Сплаў]] [[bs:Legura]] [[bg:Сплав]] [[ca:Aliatge]] [[cs:Slitina]] [[da:Legering]] [[de:Legierung]] [[et:Sulam]] [[el:Κράμα]] [[es:Aleación]] [[eo:Alojo]] [[fa:آلیاژ]] [[fr:Alliage]] [[gd:Coimheatailt]] [[gl:Aliaxe]] [[ko:합금]] [[hr:Legura]] [[io:Aloyo]] [[id:Aloy]] [[is:Málmblanda]] [[it:Lega (metallurgia)]] [[he:סגסוגת]] [[sw:Aloi]] [[lt:Lydinys]] [[mk:Легура]] [[ms:Aloi]] [[mn:Хайлш]] [[nl:Legering]] [[ja:合金]] [[no:Legering]] [[nn:Legering]] [[nrm:Alouai]] [[ug:قېتىشماق]] [[uz:Qotishma]] [[pl:Stop metali]] [[pt:Liga metálica]] [[ro:Aliaj]] [[ru:Сплав]] [[simple:Alloy]] [[sl:Zlitina]] [[sr:Легура]] [[fi:Metalliseos]] [[sv:Legering]] [[ta:கலப்புலோகம்]] [[th:โลหะผสม]] [[vi:Hợp kim]] [[tr:Alaşım]] [[uk:Сплави]] [[yi:געמיש מעטאלען]] [[zh:合金]]