Question

Which one of the following statements about phase diagrams is NOT correct?

• A. It gives information on transformation rates
• B. Relative amount of different phases can be found under given equilibrium conditions
• C. It indicates the temperature at which different phases start to melt
• D. Solid solubility limits are depicted by it

Hint:

Phase diagrams show equilibrium phase relationships, while TTT and CCT diagrams provide transformation rate information.

Answer 1

The Correct Option is A

A phase diagram provides information about phase stability, transformation temperatures, and solubility limits of different phases under equilibrium conditions. However, it does not provide details about the rate of phase transformations. Step 1: Understanding the Statements - Option (A) - Incorrect: Phase diagrams do not give information on transformation rates; this is instead provided by Time-Temperature-Transformation (TTT) diagrams.
- Option (B) - Correct: Phase diagrams show the relative amounts of different phases using the lever rule.
- Option (C) - Correct: They indicate melting points and phase transition temperatures.
- Option (D) - Correct: Phase diagrams depict solid solubility limits, which define solubility boundaries in alloy systems.


Step 2: Conclusion Since phase diagrams do not provide information about transformation rates, option (A) is incorrect, making it the correct answer.