Question

Match the following:

• A. A-I, B-II, C-III, D-IV
• B. A-III, B-IV, C-I, D-II
• C. A-IV, B-III, C-II, D-I
• D. A-III, B-IV, C-II, D-I

Hint:

Voids are essentially clusters of vacancies stabilized by diffusion and stress fields.

Answer 1

The Correct Option is A

Concept: Void formation in solids is a diffusion-driven defect process. It involves: - creation of vacancies due to thermal energy - movement and clustering of vacancies - annihilation at sinks like grain boundaries - influence of stress fields on void growth

Step 1: Vacancy creation (A).
Vacancies are generated due to thermal excitation: \[ \text{Atoms leave lattice sites} \rightarrow \text{vacancies form} \] So: \[ A \rightarrow I \]

Step 2: Vacancy annihilation (B).
Vacancies are removed when they reach: - grain boundaries - dislocations So: \[ B \rightarrow II \]

Step 3: Void nucleation (C).
When vacancies cluster together: \[ \text{vacancy clusters} \rightarrow \text{voids} \] So: \[ C \rightarrow III \]

Step 4: Stress suppression (D).
Applied stress affects void stability and suppresses pore growth in certain directions: \[ D \rightarrow IV \] Final Answer: \[ \boxed{A-I,\; B-II,\; C-III,\; D-IV} \]