duktil

Duktil, or ductile in English, is a material property describing the ability to undergo substantial plastic deformation before fracture. Materials with high ductility can be stretched into wires or elongated into larger shapes without cracking. Ductility is a key indicator of toughness and formability in engineering design.

It is commonly measured in tensile tests, where elongation at fracture and reduction of area are reported as percentages. True plastic strain and the presence of necking are also used to assess ductility. In general, ductile materials deform by slip and dislocation motion across multiple crystallographic planes.

Ductility depends on temperature, strain rate, composition, and microstructure. Metals with face-centered cubic (FCC) structures typically exhibit higher ductility than those with hexagonal close-packed (HCP) or body-centered cubic (BCC) structures at room temperature. Grain size, work hardening, and the distribution of second-phase particles influence how easily dislocations move. Impurities can cause embrittlement, while certain alloying elements can improve ductility.

Fracture behavior differs: ductile fracture involves significant plastic deformation and the formation of microscopic voids that coalesce, often with a dimpled surface; brittle fracture occurs with little or no plastic deformation and rapid crack propagation. Some materials show a ductile-to-brittle transition at low temperatures, while others remain largely ductile across wide temperature ranges.

Applications rely on ductility for safety and manufacturability. Ductile metals are preferred for forming processes such as drawing, rolling, and stamping, and for structural components that must absorb impact energy. Ductility is closely related to toughness, though high ductility alone does not guarantee high toughness without sufficient strength.