What does ductility measure in materials?

Ductility measures the ability of a material to deform under tensile stress without breaking. This property is critical in many engineering applications, where materials experience stretching or pulling forces. When a ductile material is subjected to tensile stress, it can elongate significantly before failure, allowing for more significant deformation without catastrophic results. Ductility is particularly important in construction and manufacturing, where materials are often expected to bend or stretch without breaking, contributing to their overall toughness and reliability.

In the context of comparing it with the other choices, the ability to conduct electricity pertains to electrical conductivity, which is a separate property altogether. The ability to withstand high temperatures involves thermal resistance, which is not directly related to ductility. Resistance to fracture, while related to overall toughness and impacted by ductility, specifically refers to a material's ability to resist breaking under various types of stress, including compressive and shear stress, rather than just tensile stress alone. Thus, ductility's specific focus on deformation under tensile stress delineates it clearly from these other mechanical properties.