| Abstract from DBPedia | An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, opacity, and luster, but may have properties that differ from those of the pure metals, such as increased strength or hardness. In some cases, an alloy may reduce the overall cost of the material while preserving important properties. In other cases, the mixture imparts synergistic properties to the constituent metal elements such as corrosion resistance or mechanical strength. Alloys are defined by a metallic bonding character. The alloy constituents are usually measured by mass percentage for practical applications, and in atomic fraction for basic science studies. Alloys are usually classified as substitutional or interstitial alloys, depending on the atomic arrangement that forms the alloy. They can be further classified as homogeneous (consisting of a single phase), or heterogeneous (consisting of two or more phases) or intermetallic. An alloy may be a solid solution of metal elements (a single phase, where all metallic grains (crystals) are of the same composition) or a mixture of metallic phases (two or more solutions, forming a microstructure of different crystals within the metal). Examples of alloys include red gold (gold and copper) white gold (gold and silver), sterling silver (silver and copper), steel or silicon steel (iron with non-metallic carbon or silicon respectively), solder, brass, pewter, duralumin, bronze, and amalgams. Alloys are used in a wide variety of applications, from the steel alloys, used in everything from buildings to automobiles to surgical tools, to exotic titanium alloys used in the aerospace industry, to beryllium-copper alloys for non-sparking tools.合金（ごうきん、英: alloy）とは、単一の金属元素からなる純金属に対して、複数の金属元素あるいは金属元素と非金属元素から成る金属様のものをいう。純金属に他の元素を添加し組成を調節することで、機械的強度、融点、磁性、耐食性、自己潤滑性といった性質を変化させ材料としての性能を向上させた合金が生産されて様々な用途に利用されている。 一言に合金といっても様々な状態があり、完全に溶け込んでいる固溶体、結晶レベルでは成分の金属がそれぞれ独立している共晶、原子のレベルで一定割合で結合した金属間化合物などがある。合金の作製方法には、単純に数種類の金属を溶かして混ぜ合わせる方法や、原料金属の粉末を混合して融点以下で加熱する焼結法、化学的手法による合金めっき、ボールミル装置を使用して機械的に混合するメカニカルアロイングなどがある。ただし、全ての金属が任意の割合で合金となるわけではなく、合金を得られる組成の範囲については、物理的・化学的に制限（あるいは最適点）が存在する。 (Source: http://dbpedia.org/resource/Alloy) |
