# 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-IV

1. (a) What is electromagnetic radiation? Explain the properties of Electromagnetic radiation

(b) Write short notes on Stereographic projections.

2. (a) For BCC Iron, compute (i) the interplanar spacing (ii) the diffracting angle for the (220) set of planes. The lattice parameter of Iron is 0.2889 nm. Assume that a monochromatic radiation having a wavelength of 0.1541 nm is used and the order of reflection is done.

(b) (i) Calculate the interplanar spacing for (110) and (221) sets of planes in Aluminum (ii) When a monochromatic X-ray beam of X-rays of wavelength 0.1542 nm is used, the first order reflection from (113) set of planes occurs at ? .What is the value of ??

3. Explain the following:

(a) Measurement of X-ray intensity

(b) Stereographic projection

(c) Resolving power of a Camera.

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) The transmission Laue Pattern is made up of Copper Crystal with a specimen to film distance of 4 Cm. The (111) planes of the Crystal make an angle 4o with the incident beam. What minimum tube voltage is required to produce

(111) reflection?

(b) Why is a diffractometer used for the measurement of the intensity of X-rays.

Explain the general features of this diffractometre.

6. Write notes on the following:

(a) Depth of X-ray penetration

(b) Crystal orientation [5]

(c) Special diaffractometer.

7. A Transmission pinhole photograph is made of a sheet of Aluminum 0.5 mm thick with Cu K? radiation. Consider only the (111) reflection which occurs at 2? = 38.40. Imagine the sheet to be divided into four layers, the thickness of each being equal to one fourth of the total thickness. Calculate the fraction of the total diffracted energy for each layer.

8. Compare and Contrast Coherent and Incoherent radiation.