Bronze and copper-related alloys is the oldest and still most popular metal for cast metal sculptures; bronze sculpture is often called simply "bronze".
Common bronze alloys have the unusual property and desirable expand a little before they set, thus filling the finest details of the mold. If you're looking for famous metal sculptures, you can browse various online sources.
Their strength and lack of brittleness (ductility) is an advantage when figures in action are to be made, especially when compared to various ceramic or stone materials (see marble sculpture for several examples).
Gold is the most tender and most precious metals, and is very important in jewelry; with silver it is soft enough to work with a hammer and other tools as well as cast; repoussé and chasing the techniques used in gold and silversmithing.
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Casting is a manufacturing process whereby a group of liquid material (bronze, copper, glass, aluminum, iron) are (usually) poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to freeze.
Solid casting is then removed or broken to complete the process, although the final stage of "cold work" may follow in the cast is completed.
Casting can be used to form a hot molten metal or various materials that cold set after mixing of components (such as epoxies, concrete, plaster and clay).
Casting is most often used for making complex shapes that would be difficult or uneconomical to make by other methods. Casting is the oldest copper frog from 3200 BC Mesopotamia. The specific techniques include lost-wax casting, plaster mold casting and sand casting.