DUCTILITY

Ductility is the ability of a Material, particularly a Metal, to undergo significant plastic deformation under a tensile stress before breaking — typically by being drawn into a wire without fracturing. It is distinct from Malleability, which describes the same ability under compressive or impact stress, such as Stamping or Rolling: a Metal can be very ductile without being as malleable, and vice versa, although both properties arise from the same physical mechanism, the slip of dislocations within the crystal lattice. Gold, the most ductile of known Metals, can be drawn into a monoatomic wire; Silver and, to a lesser extent, Copper and certain brasses are also among the ductile metals. In watchmaking and related crafts, this property allows the wire drawing of fine wires intended for jewelry, filigree or certain springs. Ductility depends on the purity of the metal, its crystalline structure and its state: Cold working, by multiplying dislocations that hinder one another, reduces it and hardens the material, while annealing restores it by releasing the internal stresses accumulated during cold work.