Brass
. Brass (alloy), alloy of copper and zinc. Harder than copper, it is ductile and can be hammered into thin leaves. Formerly any alloy of copper, especially one with tin, was called brass, and it is probable that the “brass” of ancient times was of copper and tin. The modern alloy came into use about the 16th century. The malleability of brass varies with its composition and temperature and with the presence of foreign metals, even in minute quantities. Some kinds of brass are malleable only when cold, others only when hot, and some are not malleable at any temperature. All brass becomes brittle if heated to a temperature near the melting point. To prepare brass, zinc is mixed directly with copper in crucibles or in a reverberatory or cupola furnace. The ingots are rolled when cold. The bars or sheets can be rolled into rods or cut into strips that can be drawn out into wire.