Which of the following is a property of metals that enables them to absorb energy by plastic deformation?

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

Answer: (D)

Toughness describes how much energy a metal can absorb before it fractures. When a metal with cracks or flaws is loaded, it can deform plastically around the flaw, dissipating energy as plastic work. This energy absorption slows crack growth and delays fracture, which is why toughness is the property that best explains absorbing energy by plastic deformation.

Hardness is about resisting surface indentation, malleability is the ability to deform under compressive forces to form sheets, and ductility is the ability to elongate under tensile loads. While related to deformation, only toughness directly measures energy absorbed up to fracture through plastic deformation, making it the most relevant concept here.