Ductility steel
Ductility is a mechanical property of metals that describes their ability to deform, stretch, or thin without breaking or becoming brittle or weak under stress. For example, when steel is said to be ductile, it means that it can be stretched considerably without losing its integrity.
This feature is critical for manufacturers, as a solid understanding of ductility is essential to ensure the safety and smooth operation of their machinery.
Which metals are ductile?
Copper is an example of a ductile metal, as it can be drawn into long, thin wires without breaking, unlike bismuth, which has low ductility and would fracture. Ductility allows metals such as gold, one of the most ductile, to be drawn to minimal thicknesses, making it easy to use in jewelry.
In addition, ductile alloys in steel cables make large construction projects such as bridges and pulley mechanisms possible.
There are many ductile metals, including:
- Copper
- Aluminum
- Low carbon steel
- Gold
- Silver
- Tin
- Lead
How to measure ductility?
Ductility is measured in two ways: percent elongation, which indicates how much a metal stretches from its original length after a tensile test, and percent reduction, which measures the decrease in cross section at the narrowest part of the metal after fracture.
The ductility of a metal can vary depending on the temperature, so it is important to consider the thermal conditions to which it will be exposed in its use. Most metals have a ductile-brittle transition graph, which can be useful in evaluating their behavior at different temperatures.
Ductility vs. Malleability
Ductility and malleability are distinct properties that are often confused. Ductility refers to a metal’s ability to stretch under tensile forces, while malleability measures its ability to withstand compression, such as when hammered, pressed, or rolled.
Although a metal can be both ductile and malleable, these characteristics do not always coincide; for example, aluminium is very malleable but not highly ductile due to its atomic structure. The crystal structure of metals determines their behaviour under stress, allowing ductile metals to stretch easily and malleable metals to resist compression without breaking their atomic bonds.