Aluminum alloy is a metallic material made from a combination of
aluminum and another element, although aluminum remains the primary
component. Silver in color, aluminum is a lightweight element that is
ductile and resistant to corrosion. There are a large number of aluminum
alloys that may be made from various combinations of elements.
Aluminum alloys are produced by alloy suppliers much like other popular alloys are produced. They can be wrought or cast into their new chemical make-up. Alloy castings involve melting down the aluminum and then whatever other substance, be it magnesium, silicon, iron or lithium is going to be mixed in with it to produce the alloy. Then the die-casting process mixes the substances creating the new, as well as giving the aluminum alloy a shape as it cools in the die-casting. Magnesium alloys are produced in this fashion as well. Wrought aluminum is also melted, although not to the extreme stage required by casting, and it is also hammered and pressed before it hardens, ensuring a smooth and uniform mixture. Wrought alloys have greater strength and ductility then cast alloys. Aesthetically, aluminum alloys are preferred by some industries because their surface remains shiny in a dry environment due to the formation of a clear, protective layer of aluminum oxide that develops during the casting or wrought process.
There are vast amounts of aluminum alloy combinations. Some of the most common aluminum alloys include Al-Li, a combination of aluminum and lithium; duralumin, a combination of aluminum and copper
; magnox, a mix of aluminum and magnesium oxide; and silumin, a combination of aluminum and silicon. Other aluminum alloys are not formally named but instead referenced by a number, such as 2011 aluminum, a combination of seven elements that is used for screw machine stock. Each aluminum alloy is used for different applications, according to the properties gained by the mixed composition. For example, Al-Li is significantly lighter than pure aluminum, since lithium is the lightest of the metallic elements. Because of its lightweight composition, Al-Li is often used for applications in the aerospace industry. Another aluminum alloy that is salt-water corrosion resistant and therefore used in marine applications involves mostly magnesium with smallish doses of iron and chromium as well. Various degrees of magnesium aluminum alloys are also used for decorative pieces and architectural uses, since they take well to anodizing treatments.