Which property is defined as the maximum stress a material can withstand before it breaks?

Which property is defined as the maximum stress a material can withstand before it breaks?

• A. Yield strength
• B. Hardness
• C. Ductility
• D. Ultimate Tensile Strength (UTS)

Answer: (D)

The maximum stress a material can withstand in tension before it breaks is the ultimate tensile strength. In a tensile test, the material is pulled and stress (force divided by the original cross-sectional area) is plotted against strain. The curve rises to a peak, which represents the highest engineering stress the material can endure—the point of ultimate tensile strength. After reaching this peak, the specimen typically necks and eventually fractures, so no higher stress is sustained.

This is different from yield strength, which is the stress level at which permanent (plastic) deformation begins and the material stops behaving elastically. Ductility describes how much deformation the material can undergo before fracture, often shown as elongation or reduction in area. Hardness measures resistance to localized plastic deformation (like indentation) and does not directly quantify the stress the material can bear in tension.