Material Technology - May 2015

Mechanical Engineering (Semester 4)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.

Answer any four from the following:

1 (a) Discuss the allotropic modifications of pure Iron.(5 marks) 1 (b) Define fracture and discuss various types of fracture.(5 marks) 1 (c) What are dislocations? Classify them and discuss any one of them.(5 marks) 1 (d) What is nitriding? How is it practised?(5 marks) 1 (e) What are composites? Give a classification of composites.(5 marks) 2 (a) What is deforming? Explain the slip mode of deformation.(7 marks) 2 (b) Define Fatigue. Draw the S-N curve and explain its interpretation.(7 marks) 2 (c) Derive an expression for CRSS.(6 marks) 3 (a) Draw a neat and labelled Fe-Fe₃C diagram.(7 marks) 3 (b) Discuss the cooling of 0.4%C steel.(6 marks) 3 (c) Explain the method of carburizing; also give example of parts that are carburized.(7 marks) 4 (a) State Griffith's criteria of brittle fracture and derive the equation.(7 marks) 4 (b) Draw neat and labelled micro-structures of grey cast iron, 0.8%C steel and low carbon steel.(7 marks) 4 (c) Define Hardenability and discuss factors affecting it.(6 marks) 5 (a) What are the various methods used for processing of polymers? Explain any one in detail.(7 marks) 5 (b) What are High speed steels? How are they heat treated?(7 marks) 5 (c) How are stainless steels classified? Discuss their properties and applications.(6 marks)

Write short notes on any four:

6 (a) Recrystallisation annealing(5 marks) 6 (b) Stages of Creep(5 marks) 6 (c) Methods used for nano materials synthesis.(5 marks) 6 (d) TTT diagram and its importance(5 marks) 6 (e) Types of Cast irons.(5 marks)