Question

Which is not a feature of cold working?

• A. Increase in dislocation density
• B. Grain refinement
• C. High ductility
• D. Strain hardening

Hint:

Cold working improves strength through strain hardening but reduces ductility, making the material less pliable.

Answer 1

The Correct Option is C

Cold working refers to the process of shaping a material at a temperature lower than its recrystallization point, typically at room temperature. This process leads to various changes in the material's properties:
- Increase in dislocation density: Cold working increases the dislocation density within the material, making it harder and more resistant to further deformation.
- Grain refinement: As the material undergoes deformation, the grains become finer, improving the strength and hardness of the material.
- Strain hardening: Cold working results in strain hardening, which increases the strength and hardness of the material as the dislocations are trapped and prevented from moving.
- High ductility: Cold working typically reduces the ductility of a material, making it less capable of being stretched or deformed without breaking. This is the key feature that is not associated with cold working.
Therefore, the correct answer is high ductility, as it is not a characteristic feature of cold working.