Question

Frank–Read source

• A. Generates dislocation
• B. Hinders the movement of dislocation
• C. Is responsible for polygonization in edge dislocation
• D. Is responsible for dislocation climb

Hint:

Frank–Read source is fundamental in crystal plasticity: it explains how materials can undergo large strains due to dislocation multiplication under applied stress.

Answer 1

The Correct Option is A

The Frank–Read source is a dislocation multiplication mechanism that explains how a single dislocation can generate additional dislocations under shear stress. This mechanism plays a crucial role in explaining the work hardening and plastic deformation of crystalline materials. When stress is applied, a segment of a dislocation line pinned at both ends can bow out and loop around, producing additional dislocations in the process. These dislocation loops continue to expand and generate more dislocations, thereby contributing to plastic deformation. This process does not hinder motion or contribute to polygonization or climb — it primarily generates dislocations.