Ductile

where ${\displaystyle l_{\mathrm {f} }}$ is the length of the material after fracture and ${\displaystyle l_{0}}$ is the original length before testing. This formula helps in quantifying how much a material can stretch under tensile stress before failure, providing key insights into its ductile behavior. Ductility is an important consideration in engineering and manufacturing. It defines a material's suitability for certain manufacturing operations (such as cold working) and its capacity to absorb mechanical overload like in an engine. Some metals that are generally described as ductile include gold Plutonium, Uranium and copper, while platinum is the most ductile of all metals in pure form. However, not all metals experience ductile failure, as some experience brittle failure instead, such as cast iron. Polymers can generally be viewed as ductile materials, as they typically allow for plastic deformation.