Question

For a ductile material, toughness is a measure of

• A. Resistance to indentation
• B. Ability to absorb energy till elastic limit
• C. Ability to absorb energy up to fracture
• D. Resistance to scratching

Hint:

Toughness in ductile materials is the total energy absorbed (area under the stress-strain curve) up to fracture, including both elastic and plastic deformation.

Answer 1

The Correct Option is C

Step 1: Understand the concept of toughness in materials science.
Toughness is a material property that quantifies its ability to absorb energy and deform plastically before fracturing. It is particularly relevant for ductile materials, which undergo significant plastic deformation before breaking. Step 2: Define toughness for a ductile material.
Toughness is measured as the total energy absorbed per unit volume up to the point of fracture.
In a stress-strain curve for a ductile material, toughness is the area under the entire curve (from the origin to the fracture point), including both elastic and plastic deformation regions.
This distinguishes toughness from:
Resilience: The ability to absorb energy in the elastic region (area under the curve up to the elastic limit).
Hardness: Resistance to indentation or scratching.
Step 3: Evaluate the options.
(1) Resistance to indentation: This describes hardness (e.g., measured by Brinell or Vickers tests), not toughness. Incorrect.
(2) Ability to absorb energy till elastic limit: This describes resilience, not toughness, as toughness includes plastic deformation up to fracture. Incorrect.
(3) Ability to absorb energy up to fracture: This correctly defines toughness for a ductile material, as it accounts for both elastic and plastic energy absorption. Correct.
(4) Resistance to scratching: This is another measure of hardness, not toughness. Incorrect. Step 4: Select the correct answer.
For a ductile material, toughness is the ability to absorb energy up to fracture, matching option (3).