<P> An alloy is a combination of metals or of a metal and another element . Alloys are defined by a metallic bonding character . An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). Intermetallic compounds are alloys with a defined stoichiometry and crystal structure . Zintl phases are also sometimes considered alloys depending on bond types (see also: Van Arkel--Ketelaar triangle for information on classifying bonding in binary compounds). </P> <P> Alloys are used in a wide variety of applications . In some cases, a combination of metals may reduce the overall cost of the material while preserving important properties . In other cases, the combination of metals imparts synergistic properties to the constituent metal elements such as corrosion resistance or mechanical strength . Examples of alloys are steel, solder, brass, pewter, duralumin, bronze and amalgams . </P>

A mixture of two or more elements one of which is a metal