The property describing the extent to which a material can undergo plastic deformation before breaking is called what?

• A. Ductility
• B. Malleability
• C. Toughness
• D. Hardness

Answer: (A)

Ductility is the ability of a material to undergo significant plastic deformation before fracture. This property tells you how far a material can be stretched or deformed plastically before it breaks, which is why metals that are ductile can form necking and still absorb noticeable amounts of energy before failing. In tensile testing, ductility is often measured by the percentage elongation or the percentage reduction in cross-sectional area at fracture, indicating how much the material has stretched or narrowed during loading.

Malleability refers to deforming under compressive forces to form thin sheets, like shaping metal into sheets, which is a related idea but not the same as how much it can plastically deform before breaking in tension.

Toughness describes the total energy a material can absorb before fracture, combining strength and ductility, but it doesn’t specify the extent of plastic deformation by itself.

Hardness is about resisting indentation or localized plastic deformation and isn’t a direct measure of how much a material can deform before breaking.