Toughness of a Ductile Material

The toughness of a material is a measure of its ability to absorb energy up to fracture. It is an important property when considering the performance and reliability of a material under different loading conditions. In the case of a ductile material, toughness is particularly significant.

Definition of Toughness
Toughness is defined as the amount of energy per unit volume that a material can absorb before fracturing. It is a measure of the material's ability to deform plastically in the presence of an applied load.

Reason for Correct Answer (Option B)
The correct answer, option B, states that toughness is a measure of the ability of a ductile material to absorb energy up to fracture. This is accurate because ductile materials, by definition, have the ability to undergo large deformations without fracturing. When a ductile material is subjected to an applied load, it deforms plastically before eventually reaching its fracture point.

Explanation of Other Options
- Option A: Resistance to scratching is not related to toughness. The ability to resist scratching is more related to the hardness of a material.
- Option C: The ability to absorb energy till the elastic limit is a measure of a material's resilience, not toughness. Resilience refers to the ability of a material to store and release elastic energy.
- Option D: Resistance to indentation is not directly related to toughness. Indentation resistance is typically associated with a material's hardness or resistance to localized deformation.

Importance of Toughness in Ductile Materials
In engineering applications, ductile materials are often preferred over brittle materials due to their ability to deform plastically before fracturing. This property is particularly important in situations where the material is subjected to impact or dynamic loading conditions.

When a material is subjected to an impact load, it experiences rapid loading rates, which can lead to the formation of stress concentrations. Ductile materials with high toughness can absorb the energy associated with these stress concentrations and deform plastically before reaching their fracture point. This helps prevent catastrophic failure and allows for more reliable performance of the material.

Conclusion
In summary, toughness is a measure of a material's ability to absorb energy up to fracture. In the case of ductile materials, toughness is particularly important as they have the ability to deform plastically before fracturing. This property allows ductile materials to withstand impact or dynamic loading conditions more effectively.