Question

Which of the following material is dimensionally stable after a period of aging?
1. Grey cast iron
2. Silver oxide
3. Copper nitrate
4. H₂O

Answer 1

Correct Answer - Option 1 : Grey cast iron

Explanation:

• For the precipitation heat treatment, the supersaturated α solid solution is ordinarily heated to an intermediate temperature T₂ within the α +β two-phase region, at which temperature diffusion rates become appreciable.
• The β precipitate phase begins to form as finely dispersed particles of composition C_β, which process is called "Aging".
• Grey cast iron is the material that is dimensionally stable after a period of aging.