JNTU II B.Tech I Semester Regular Examinations, November 2008

JNTU II B.Tech I Semester Regular Examinations, November 2008

PHYSICAL METALLURGY

(Metallurgy & Material Technology)

SET-1

 

1. Describe the optical features of a Metallurgical microscope with a neat sketch?

 

2. (a) What are the miller indices of a plane in the cubic structure that goes through

y=1/2, z=1 and is parallel to the X-axis? Draw the cubic structure and cross

hatch this plane.

(b) If copper is FCC and has a lattice parameter of 2.556A0, calculate the lattice

parameter?

 

3. Write short notes on:

(a) Ionic solids

(b) Electron compounds.

 

4. Explain the following terms:

(a) Solidus line

(b) Liquidus line

(c) Solvus line

(d) Eutectic.

 

5. (a) Compare and contrast the allotropy and Order – disorder transformation.

(b) In a phase transformation an appreciable rate of nucleation of 106 m?3 s-1

occurs at room temperature when the critical nucleation energy is 2.07 ×10?19 J. The energy of the interface between the product and parent phases is0.05 J M?2. Calculate the nucleation rate, if the interfacial energy had been 10% larger than this.

 

6. (a) Write a note on solid solubility of carbon in ? Iron.

(b) Write a note on solid solubility of carbon in ? Iron.

7. (a) What is annealing? What are its aims?

(b) Full annealing is the most common type of annealing. Give the temperature ranges and explain how the different aims are attained by it?

 

8. Draw I – T diagram for SAE 4815 steel (0.16% C, 0.52% Mn, 3.36% Ni, 0.19% Mo)

for uncarburized and carburized conditions. Also discuss the effect of low and high carbon content on the shape and characteristics of I -T curves when all the other variables are essentially constant.

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