How are the properties of ductility and brittleness different?

• A. Ductility is the ability to deform plastically before fracture; brittleness is little to no plastic deformation before fracture.
• B. Ductility equals brittleness.
• C. Both refer to hardness.
• D. Ductility refers to color change.

Answer: (A)

How a material behaves as it approaches fracture is being tested here: whether it can deform a lot before breaking or whether it fractures with almost no plastic deformation. Ductility is the ability to sustain substantial plastic deformation before fracture, so a ductile metal can be stretched into shapes like wires, shows noticeable thinning (necking), and absorbs a lot of energy before failure. Brittle materials, in contrast, crack and snap with very little plastic deformation, absorbing little energy and often giving little warning before breaking. This difference matters in design: ductile materials can redistribute stress around flaws and deform to accommodate loads, reducing sudden failures, while brittle materials may fail abruptly under impact or stress concentrations. Examples help: steel or copper are ductile; glass or cast iron are brittle. The other ideas don’t fit: hardness is about resistance to surface indentation, not how much a material deforms before breaking, and color change is unrelated to ductility.