JNTU IV B.Tech I Semester Supplimentary Examinations, February 2008

JNTU IV B.Tech I Semester Supplimentary Examinations, February 2008

X-RAY METALLOGRAPHY

(Metallurgy & Material Technology)

SET-III

1. (a) Explain with a neat sketch, the order of reflection.

 

(b) The atomic radius of Molybdenum atom is 0.1363 nm. Compute the interatomic spacing for (111) set of planes in the molybdenum crystal. The crystal structure of molybdenum is bcc. What is the interplanar spacing for (220) set of planes?

 

2. (a) In a drawing of a hexagonal prism, indicate the following planes and directions:

(1210), (1012), (1011), [110], [111], [021]. Show cell axes.

(b) What is Stereographic Projection? Show the lattice reorientation caused by turning on stereographic projection.

 

3. (a) Describe Laue method of X-ray diffraction.

(b) What does the each intense point in X-ray diffraction represent in Laue pat- tern? Explain.

 

4. (a) How does Debye-Scherrer diffraction pattern look?

(b) Where is Debye-Scherrer method useful?

(c) Explain how a powder camera is superior to a Diffractometer with examples.

 

5. (a) With a neat sketch explain back-reflection Lane method.

(b) A Powder specimen in the form of a rectangular plate has a width of 0.45 in., measured in the plane of the diffractometre circle, which has a radius of 4.37 in. If it is required that the specimen entirely fill the incident beam at all angles and that measurements must be made to angles as low as 2? = 120 , what is the maximum divergence angle that the incident beam may have?

 

6. What is the principle involved in transmission Laue method? With a neat sketch explain the transmission Laue method?

 

7. With an example discuss the structure determination in detail.

 

8. Compare and Contrast Coherent and Incoherent radiation.

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