Question

Work hardening is also called

• A. Twinning
• B. Slip
• C. Hardening
• D. Strain hardening

Hint:

The terms "work hardening," "strain hardening," and "cold working" are closely related. Cold working is the process (deforming below the recrystallization temperature), and work/strain hardening is the resulting increase in strength.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Work hardening is the phenomenon whereby a ductile metal becomes harder and stronger as it is plastically deformed. This is a fundamental concept in materials science and manufacturing.

Step 2: Detailed Explanation:

• Work Hardening Mechanism: Plastic deformation (or "work") occurs primarily by the creation and movement of dislocations. As deformation proceeds, the dislocation density increases. These dislocations interact, entangle, and obstruct each other's movement, making further deformation more difficult. This resistance to further deformation manifests as an increase in strength and hardness.

• (D) Strain hardening: Since this hardening effect is a direct result of imposing plastic strain on the material, the term "strain hardening" is used as a direct synonym for "work hardening."

• (A) Twinning and (B) Slip: These are mechanisms of plastic deformation. Slip is the primary mechanism that causes work hardening, but it is not the name for the hardening effect itself. Twinning is an alternative deformation mechanism.

• (C) Hardening: This is a very general term. There are many ways to harden a metal (e.g., precipitation hardening, solid solution hardening, quenching). Work hardening is just one specific type. "Strain hardening" is the specific and correct synonym.

Step 3: Final Answer:
The most common and accurate synonym for work hardening is strain hardening.