JNTU Exam Papers,II B-Tech I Sem Supplimentary Exams,Physical Metallurgy,February 2008

JNTU Exam Papers

II B.Tech I Semester Supplimentary Examinations, February 2008
PHYSICAL METALLURGY
(Metallurgy & Material Technology

SET-I

1. Give an account on the following:
(a) Condenser system
(b) Light filters
(c) Objective lens
2. (a) What is allotropy? Discuss various allotropic forms of iron and their properties.
(b) Explain why increase of pressure may give allotropic transformation to close packed structure?
3. (a) What is the necessity of alloying?
(b) Distinguish between substitutional and interstitial solid solutions.
(c) Explain the Hume-Rothery rules for the formation of extensive solid solution.

4. (a) Explain the differences between
i. Coherent
ii. Partially coherent
iii. Incoherent interfaces.
(b) Explain how does the interfacial energy vary with coherency.
5. (a) Explain in detail with suitable examples the eutectoid and peritectoid reactions that take place in various phase-diagrams.
(b) How are equilibrium diagrams related to the mechanical properties of the  system which they represent? Explain?
6. (a) Compute the mass fraction of ferrite and cementitie in pearlite.
(b) Explain the differences between hypo eutectoid and hypereutectoid steels.
(c) In a hypo eutectoid steel both eutectoid and proeutectoid ferrite exist. Explain the differences between them.
7. (a) What are quench cracks? Explain the possible reasons for their formation? How to avoid their formation
(b) Distinguish between ‘retained austenite’ and stabilized austenite.

8. What do you mean by TTT diagrams. Describe the method of constructing TTT diagrams for an eutectoid steels. Label the various phases in the TTT diagram.

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