Cold work is work hardening; decreases ductility.

Cold work is work hardening; decreases ductility.

• A. Increases ductility
• B. Occurs only at high temperature
• C. Decreases ductility and makes metal harder and stronger
• D. Softens metal

Answer: (C)

Cold work, or work hardening, happens when metal is deformed at room temperature. The deformation creates a high density of dislocations, and their interactions block further movement of other dislocations. This makes the material stronger and harder while reducing its ability to undergo additional plastic deformation, i.e., lowers ductility. That’s why the correct description is that cold work decreases ductility and makes the metal harder and stronger. It does not increase ductility, it is not limited to high-temperature processes, and it does not soften the metal. (Ductility can be restored by annealing, if needed.)

Cold work, or work hardening, happens when metal is deformed at room temperature. The deformation creates a high density of dislocations, and their interactions block further movement of other dislocations. This makes the material stronger and harder while reducing its ability to undergo additional plastic deformation, i.e., lowers ductility. That’s why the correct description is that cold work decreases ductility and makes the metal harder and stronger. It does not increase ductility, it is not limited to high-temperature processes, and it does not soften the metal. (Ductility can be restored by annealing, if needed.)