Elongation and reduction of area after fracture indicate which property?

• A. Ductility
• B. Hardness
• C. Brittleness
• D. Stiffness

Answer: (A)

Elongation and reduction of area after fracture show how much a material can plastically deform before breaking, which is ductility. In a tensile test, a ductile metal will neck and stretch significantly, losing cross-sectional area in the process; the percent elongation and percent reduction in area quantify this behavior. High values mean the material can deform a lot before failing. Hardness measures resistance to indentation, not post-failure deformation. Brittleness is the tendency to fracture with little plastic deformation, so it would show small elongation and little reduction in area. Stiffness refers to the elastic response (Young’s modulus), not the amount of plastic deformation after fracture.