Copper alloy is a metallic material made from a combination of copper and another element, in which copper is the main component. Several hundred different kinds of copper alloys, loosely grouped into larger categories, are possible. Some of the most common copper alloy categories include brasses, copper nickels, and bronzes.

The two processes that produce alloys of all sorts, including copper alloys, is to cast them and to wrought them. Both of these techniques involve melting, although casting the copper with another metal substance requires both to be completely molten, while wrought alloys are not fully liquid. Also, casting does not involve hammering or pressing, as the wrought process does. Depending on what application the copper alloy is for, it may be wrought or cast; the two techniques produce a couple different characteristics. One way copper alloys are employed is as brazing alloys, which means they serve as the metal filler that is torched to a melting point and when dries, is melding to other pieces of metal together. Other alloys that are commonly used in this fashion are silver alloys, nickel alloys, gold alloys and aluminum alloys.
Alloyed metals with copper bases are as well known in the consumer context as copper itself. The metal brass is actually a copper alloy made by combining the copper with zinc. Although the specific compositions among versions vary, brass consistently contains more copper than zinc. Bronze, on the other hand, is a copper alloy composed of copper and tin. The chemical composition of bronze typically hovers around 60% copper material and 40% tin, although it can contain small amounts of various other elements. Copper nickel alloys, often called cupronickel, are made from a combination of copper, nickel and minute quantities of other elements, such as iron. Copper is noted for its conductive abilities and is therefore often used in electric and heating applications, especially for the manufacture of electric cords and cables. Because it resembles gold, brass is used most often for decorative reasons. Bronze, in contrast, is often employed to make musical instruments, sculptures, and various small components. Unlike some other copper alloys, cupronickel resists corrosion from salt water, and for this reason is often used to make components for the marine industry.