Material Science and Engineering

Answer FIVE questions, taking ANY TWO from Group A, ANY TWO from Group B and ALL from Group C. All parts of a question (a, b, etc) should be answered atone place, Answer should be brief and to-the-point and be supplemented with neat sketches. Unnecessary long answers may result in loss of marks. Any missing data ,or wrong data may be assumed suitably giving proper justification. Figures on the right-hand side margin indicate full marks. 1. (a) What is a Burger vector? Show it by drawing a Burger circuit? What is Frank-Read source? State its importance in plastic deformation. 2+2+2 (b) Distinguish between: (2x2)+ (2x2) (i) Slip and Cross slip (ii) Sessile dislocation and Glissile dislocation. (c) What is Critical Resolved Shear Stress? Derive its formulae. 2+2 (d) Calculate the degree of freedom of ice and water kept in a beaker at 1 atmosphere pressure. 2 2. (a) State Fick's laws of Diffusion. How can it help you m the problems of Case Carburising? Given an activation energy, Q of 142 kJ/mol, for the diffusion of carbon in FCC iron and an initial temperature of 1000 K, find the temperature that will increase the diffusion coefficient by a factor 10. [R =8.314 J/(mol.K)]: Will you use a very high temperature? 2+2+(3+1) (b) What is a Phase? What is the difference between α-iron and ferrite? Define an invariant reaction with an example. 2+2 (c) Differentiate between: (2x2)+ (2x2) (i) Phase Rule and Phase Diagram, (ii) Solvus Line and Solidus Line. 3. (a) Explain Lever Rule with a Tie Line. Find the weight percentage of pro-eutectoid ferrite just above, the eutectoid temperature of a 0 3%C-steel. 2+2 (b) Derive the relationship between True Strain and Engineering Strain. What is Resilience? Why is it important for spring material? 2+(1 +1) (c) Describe Yield Point Phenomenon. Draw the engineering stress-strain diagram of Glass. Why does necking occur during tension test of a ductile material 2+2+2 (d) Justify: 2x3 (i) Zinc is not as ductile as copper (ii) Cold working increases hardness of materials (iii) Steel is a brittle material at sub-zero atmosphere. 4. (a) Suggest one suitable material for each of the following purpose with justifications: 2x5 (i) File Cabinet (ii) WaterTap (iii) Manhole Cover (iv) Garden Chair (v) Glass Cutter.