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Name: .

Roll No.: .....

Invigilators Signature :..

CS/B.TECH(CHE)/SEM-4/CHE -403/2011

2011

MATERIAL SCIENCE & TECHNOLOGY

Time Allotted: 3 Hours Full Marks: 70

The figures in the margin indicate full marks.

Candidates are required to give their answers in their own words

as far as practicable.

GROUP A

( Multiple Choice Type Questions )

1. Choose the correct alternatives for any ten of the following :

10 1 = 10

i) Atomic packing factor for a B.C.C. crystal is

a) 520 b) 480

c) 680 d) none of these.ii) The number of tetrahedral voids in HCP unit cell is

a) 8 b) 6

c) 4 d) 12.

iii) The structure of silica is

a) non-crystalline b) crystalline

c) semi-crystalline d) both (a) & (b).

iv) The ability of material to offer resistance to scratching

or indentation is a measure of its

a) hardness b) ductility

c) fracture toughness d) stiffness.

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v) Dislocations in a crystal is due to

a) Surface imperfection b) Line imperfection

c) Point imperfection d) Volume imperfection.

vi) Brittleness of a material is due to lack of

a) Hardness b) Malleability

c) Ductility d) Fatigue resistance

vii) Corrosion resistance property of cast iron is significantly

improved by the addition of 12%-15% of

a) Tungsten b) Vanadium

c) Silicon d) Phosphorus.

viii) The configurational entropy of a fully stretched rubber

is

a) Infinite

b) Zero

c) Intermediate value between (a) & (b)

d) Negative.

ix) The four parameter model for the demonstration of

Viscoelasticity behavior of certain materials is

represented by

a) Voigt-Kelvin element

b) Maxwell element

c) Both (a) & (b) combined

d) None of these.

x) The strain hardening of metals is done by cold working

process because in this process, the dislocation density

in the metal structure

a) increases b) decreases

c) does not change d) completely removed.

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xi) Leaching is a unit operation undera) Electrometallurgy b) Hydrometallurgy

c) Pyrometallurgy d) Powder metallurgy.

xii) The reaction that on heating one solid phase yields

another solid phase and one liquid phase is called

a) Eutectic b) Peritectic

c) Eutectoid d) Peritectoid.

GROUP B

( Short Answer Type Questions )

Answer any threeof the following.

3 5 = 15

2. What is slag ? Differentiate between calcinations and

roasting with example. 5

3. Explain in brief the structure of multiple hearth furnace

stating the function of different zones. 5

4. a) What are fluo-solids ?

b) What are the principles of hydrometallurgy and

electrometallurgy ?

c) State the different sources of copper in India. 1 + 2 + 2

5. Define creep. Explain its phases and mechanism. 5

6. Describe the mechanism of developing corrosion in metals in

the light of the electrochemical theory. 5

GROUP C

( Long Answer Type Questions )

Answer any threeof the following. 3 15 = 45

7. Explain edge dislocation. Define fatigue fracture and explain

how the fatigue life of a component be improved. What do

you understand by strain hardening ? 5 + 5 + 5

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8. a) Show the different parts of a Blast Furnance with the

help of a neat diagram.

b) Write and discuss working principles of different other

equipment in association of it.

c) Classify different types of slag on the basis of chemical

nature. 6 + 6 + 3

9. Define atomic packing factor. Draw a TTT diagram of

eutectoid and explain its salient features. Discuss different

types of surface imperfection that may be present in real

materials. 2 + 7 + 6

10. a) Name at least two ores of Aluminium.

b) Discuss how aluminium is extracted from Bauxite by

electrochemical process.

c) Show the chemical reactions involved in this extraction.

d) Name two alloys of Zinc with composition.

1 + 10 + 2 + 2

11. Write short notes on any two of the following.2172

a) Predominant area diagram

b) Continuous casting of steel

c) Toughness

d) Corrosion.

12. a) Explain the property and the microstructural changes

during cold working and annealing of metals.

b) Explain the mechanism of slip and twining 10 + 5