Anna University Chennai 2005 B.E Mechanical Engineering /B.TECH :Applied material science - Question Paper

B.E/B.TECH. DEGREE exam ,APRIL/MAY 2005
Fourth semester, Mechanical engineering
Applied material science

Time:3 Hrs
Maximum: 100 marks



PART A (10 X two = 20)

1. describe atomic packing factor.

2. What is screw dislocation.

3. What is meant by fracture?

4. elaborate the various mchanisms of strengthening of materials?

5. What do you understand by allotrophy?

6. Name the possible microstructure of iron and steel.

7. How does the electrical resistivity vary with composition of alloying element?

8. elaborate super hard materials?

9. What is carburising?

10.Define hardness.


PART B ( five X 16= 80)

11 (i) Draw the phase diagram for the Fe- Fe 3C alloy system and write the invariant reactions which occur in it?

(ii)What is the structure of pearlite?

12 (a) (i) What is coordination number?

(ii) Show that the atomic packing factor of HCP anf FCC are the identical.

OR

(b) hat are the point,line and surface imperfections in crystalline materials ?Bring out the difference ranging from edge and screw dislocation in crystal lattice.

13 (a) discuss in detail the mechanism of brittle fracture.Bring out the difference ranging from brittle and ductile kind of fractures

(b) describe creep .Discuss the various stages in creep curve .What are the variables that affect creep reisitant materials?

14 (a) describe mean free path.Derive an expression connecting electrical conductivity and relaxation time.

OR

(b) define the properties and uses of copper ,iron,and silver.Give the composition and uses of nichrome and constantan

15 (a) explain any 2 thermal methods of producing surface hardening of steel

OR

(b) Write short notes on

(i) Laser surface hardening

(ii) Vicker's hardness tester.

Earning:   Approval pending.