duktilnosti

Duktilnosti, commonly translated as ductility, is the ability of a material to undergo substantial plastic deformation before fracture. In engineering practice it is most often measured in a tensile test using metrics such as the percent elongation at fracture and the percent reduction of cross-sectional area. Ductile materials exhibit necking and can absorb significant energy through plastic deformation, which makes them suitable for forming, shaping, and safety applications.

Most metals, including copper, aluminum, and many steels, show notable ductility, though the degree varies with composition, heat treatment, and prior deformation. Polymers can also be highly ductile. By contrast, ceramics and many composites tend to be brittle, failing with little or no plastic deformation. Some materials may display anisotropic ductility, deforming more easily in certain directions due to their microstructure or texture.

Ductility depends on microstructure and testing conditions. Factors such as grain size, phase balance, impurities, and the history of work hardening influence ductility. Temperature generally has a strong effect: metals become more ductile at higher temperatures and can undergo ductile-to-brittle transitions at low temperatures. Strain rate also affects ductility, with higher rates often reducing the available plastic deformation before fracture.

In design, ductility is balanced with strength, hardness, and toughness. Its presence is valuable for forming processes, energy absorption in impacts, and safety margins, but excessive ductility can compromise stiffness and load-bearing capability. Related concepts include malleability, plasticity, and toughness.