JNTU Question Papers
Physical Metallurgy I-Sem Nov 2008
1. (a) What are the steps to be taken to achieve optimum resolution?
(b) Name the steps to be taken to improve the depth of field.
(c) Comment on oil immersion objectives. [4+6+6]
2. (a) Determine the number of lattice points per cell in cubic crystal systems.
(b) Determine the relationship between the atomic radius and the lattice parameter in BCC and FCC structures. [4+12]
3. (a) Define planar density and estimate the planar density value of (111) plane in
BCC and FCC unit cells. Support with due calculations.
(b) Which crystallographic planes and directions in BCC, FCC and HCP structures have highest atomic density? [8+8]
4. (a) What is a solid solution? Give the classification and explain the rules for the
formation of solid solutions.
(b) Explain why atomic size difference is only 4.2% still Zn can dissolve up to
38.4% in Cu? [8+8]
5. (a) Explain the advantages and disadvantages of a cored-dendritic structure.
(b) Which determine the micro structure of an alloy. Explain them carefully.[8+8]
6. The following data apply to binary system of A and B. Melting point of pure
A is 10500C and pure B 19000C. At 12500C, the solid solution (50% B), the ?-
solid solution (80% B) and liquid (30% B) are in 3- phase equilibrium. At room temperature, the maximum solubility of B in ?- phase is 30% and the maximum
solubility of A in ?-phase is 10%.
(a) Sketch the phase diagram of A and B showing the phases present in each area
of the diagram.
(b) What is the reaction that takes place at 12500C?
(c) What are the weight fractions of the phases present in a material of overall
composition 75% B at 12500C, 12490C at room temperature? 
7. (a) Explain with neat diagrams how the micro-structure of a pure metal may
change with additions of alloying elements.
(b) What is allotropy & Discuss various allotropic forms of Iron & their properties.
8. (a) Differentiate between CCC & TTT diagrams.
(b) Explain about the bainitic transformation. [10+6]