Material Science - Dec 2013

Mechanical Engg (Semester 3)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.

Answer any one question from Q1 and Q2

1 (a) What is work hardening? Explain the property variation with proper graph before and after work hardening.(6 marks) 1 (b) Explain the advantages of composite materials over conventional materials with suitable example.(4 marks) 1 (c) Differentiate between thermoplastic and thermosetting polymers.(2 marks) 2 (a) Differentiate between slip and twinning.(4 marks) 2 (b) Show the self explanatory diagram for point defects.(2 marks) 2 (c) Explain any one method of polymer processing, with suitable diagram.(4 marks) 2 (d) What are Cermets ?(2 marks)

Answer any one question from Q3 and Q4

3 (a) With a neat diagram explain fatigue fracture in detail.(4 marks) 3 (b) Define toughness, Notch sensitivity.(2 marks) 3 (c) What is mint by transducer, explain the respective NDT method makes the use of sound waves.(4 marks) 3 (d) What are the advantages of Dye Penetrant test over the other NDT methods.(2 marks)

Write true or false and justify your answer.

4 (a) Creep fracture is a transgranular fracture.(3 marks) 4 (b) Erichson cupping test is used for sheet metals only.(3 marks) 4 (c) For checking the hardness of phases in metals, Rockwell C scale is used.(3 marks) 4 (d) In a brass component subsurface defect can be easily determined by magnetic particle test.(3 marks)

Answer any one question from Q5 and Q6

5 (a) Explain atomization process with neat diagram used in powder production.(4 marks) 5 (b) Describe with a suitable flow chart manufacturing of cemented carbide tool.(4 marks) 5 (c) Explain the mechanism of sintering, and what is liquid phase sintering.(4 marks) 5 (d) What is spring back.(1 marks) 6 (a) Describe with a suitable flow chart manufacturing of oil impregnated bearings.(4 marks) 6 (b) What is sintering? Explain the stages of sintering.(4 marks) 6 (c) What are the disadvantages of powder Metallurgy over other conventional process.(4 marks) 6 (d) What is mint by green strength of a compact.(1 marks)

Write short note on:

7 (a) (i) Biosensors.(3 marks)

Answer any one question from Q7 and Q8

7 (a) (ii) Shape memory alloy.(3 marks) 7 (a) (iii) Nano material and their applications.(3 marks) 7 (a) (iv) Soft & Hard magnetic materials.(3 marks) 7 (b) Suggest suitable material for the replacement of heart valves.(1 marks) 8 (a) Piezoelectric materials are smart materials explain in detail.(4 marks) 8 (b) What are the property requirements in the materials / metals used for cryogenic application and suggest the suitable materials for the same.(5 marks) 8 (c) Define following (any two):
i) Biomaterials.
ii) Superconductivity.
iii) Super alloy.(4 marks)