Which property is a measure of ductility in tensile testing?

• A. Yield strength
• B. Tensile strength
• C. Ductility
• D. Hardness

Answer: (C)

The main idea here is what ductility means in a tensile test: how much plastic deformation a material can undergo before it fractures. In practice, ductility is quantified by measures like percent elongation or percent reduction in area after fracture. A material with high ductility can stretch a lot before breaking, while a brittle material shows little to no deformation before it fails. So the property that directly represents this behavior is ductility itself, captured by how much the specimen elongates or how much area is lost at fracture.

Yield strength tells you when permanent (plastic) deformation starts, not how much deformation occurs overall. Tensile strength is the maximum stress the material can bear, which is about strength, not how deformation accumulates. Hardness relates to resistance to indentation, not ductile deformation in a tensile test.