Alloy
An alloy is a combination, either in
solution or compound, of two or more
elements, at least one of which is a
metal, and where the resulting material has
metallic properties. An alloy with two components is called a binary alloy; one with three is a ternary alloy; one with four is a quaternary alloy. The resulting metallic substance generally has properties significantly different from those of its components.
Alloys are usually designed to have properties that are more desirable than those of their components. For instance,
steel is stronger than
iron, one of its main elements.
Encyclopedia
An
alloy is a combination, either in
solution or compound, of two or more
elements, at least one of which is a
metal, and where the resulting material has
metallic properties. An alloy with two components is called a binary alloy; one with three is a ternary alloy; one with four is a quaternary alloy. The resulting metallic substance generally has properties significantly different from those of its components.
Alloys are usually designed to have properties that are more desirable than those of their components. For instance,
steel is stronger than
iron, one of its main elements. It 'inherits' some of the characteristics of the elements it was made from, usually physical properties like density, reactivity and electrical and thermal conductivity. However, its engineering properties can be vastly different from its constituent materials. Among other factors, this is due to the differing sizes of the atoms in the alloy - larger atoms exert a compressive force on neighbouring atoms, and smaller atoms will exert a tensile force on their neighbours. Unlike a pure metal, where the atoms are more free to move, this helps the alloy resist deformation.
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 that at which melting is complete is called the liquidus. However, for most pairs of elements, there is a particular ratio which has a single melting point, and this is called a
eutectic mixture.
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
jewellery and the
aluminium used as a structural building material are also alloys.
The term "alloy" is sometimes used in everyday speech as a synonym for "aluminium alloy"; one example of such usage is the "alloy wheels" which might be fitted to an automobile.
See also
- List of alloys
- Intermetallics
