Question

If the material has the tendency to fracture without any appreciable deformation is known as

• A. Stiffness
• B. Brittleness
• C. Toughness
• D. Malleability

Hint:

Think of the contrast between a piece of chalk and a copper wire. If you bend the copper wire, it deforms significantly before breaking (ductile/malleable). If you try to bend the chalk, it snaps instantly with zero visible deformation. That sudden snap defines Brittleness.

Answer 1

The Correct Option is B

Concept: When materials are subjected to mechanical tensile or compressive forces, they exhibit distinct deformation and fracture characteristics. These behaviors are classified into standard engineering material properties based on their stress-strain response:
• Ductile Materials: Undergo significant permanent plastic deformation (yielding and necking) before structural failure occurs (e.g., mild steel, copper, aluminum).
• Brittle Materials: Characterized by little to no plastic deformation prior to fracture. When loaded beyond their elastic limit, they fail suddenly through rapid crack propagation along cleavage planes, showing a flat, crystalline fracture surface (e.g., cast iron, glass, ceramics).

Step 1: Evaluate the definitions of all choices.
Let us review the precise definition for each property selection listed:
• Stiffness: The capacity of a material to resist elastic deformation when a load is applied. It is quantified by Young's Modulus ($E$). A stiff material requires high stress to produce a small elastic strain, but this property does not describe the fracture mechanism.
• Brittleness: The tendency of a solid material to break or fracture suddenly with little or no appreciable plastic deformation when subjected to stress.
• Toughness: The capacity of a material to absorb energy and deform plastically before fracturing. It corresponds to the total area under the stress-strain curve from initial loading up to the point of failure.
• Malleability: A specific compressive ductility property that enables a material to be hammered, rolled, or pressed into thin sheets without cracking.

Step 2: Match the question description to the correct property.
The problem description explicitly highlights a "tendency to fracture without any appreciable deformation". This fits the exact engineering definition of Brittleness, matching Option (B).