The Institution of Engineers,India 2011 A.M.I.E Section A Section A - Question Paper
SUMMER 2011
MATERIALS SCIENCE AND ENGINEERING
Time: 3 hours
Maximum Marks: 100
ans 5 questions, taking ANY 2 from Group A,
ANY 2 from Group B and ALL from Group C.
All parts of ques. (a, b, etc.) should be answered at 1 place.
ans should be brief and to-the-point and be supple-
mented with neat sketches. Unnecessary long answers
may outcome in loss of marks.
Any missing or wrong data may be presumed suitably
Giving proper justification.
Figures on the right-hand side margin indicate full marks.
Group A
1. (a) Draw schematics to show various kinds of Bravis lattices in crystalline materials.
compute the atomic packing factor (APF) of FCC and BCC crystal structure. 6
(b) discuss the kinds of defects in crystalline materials in brief. 4
(c) Differentiate ranging from the edge and screw dislocations in terms of Burger's vector. 5
(d) obtain the equilibrium concentration of vacancies in aluminium at 0K and 900 K.
Enthalpy of formation of vacancies in aluminium, ?Hf = 68 kJmol-1';
R = 8.314 J mol-1K-1 5
2. (a) Mention and discuss Nernst-Einstein relation in diffusion . 5
(b) define Fick's 2nd legal regulations of diffusion. The diffusion coefficients for copper in
aluminium at 500°C and 600°C are 4.8 × 1014 m2/s and 5.3 × 10.13 m2/s, respectively.
compute the time needed at 500°C to produce diffusion depth equal to that at 600°C
for 10 hr 5
(c) discuss Gibbs phase rule. obtain the degrees of freedom when FCC and BCC iron co-
exist in equilibrium. 5
(d) Draw an eutectic phase diagram and discuss it. 5
three (a) Draw and discuss Fe Fe3C phase diagram Indicate the carbon percentage range of
steel. 8
(b) describe peritectic reaction. discuss with a suitable phase diagram. 6
(c) discuss the mechanism of working of zone refining process with the help of a diagram. 6
4. (a) Differentiate ranging from actual and engineering stress-strain curve. Indicate the elastic zone,
plastic zone, and yield point in a stress strain curve of mild steel. 8
(b) define visco-elastic behaviour of materials. discuss Maxwell elements and Voigt-Kelvin
model 6
(c) discuss Griffith's theory of brittle fracture. Why has silicate glass a relatively low fracture
strength ? 6
Group B
five (a) explain various methods of carburising, nitriding and carbo-nitriding. 8
(b) describe hardenability of metals. define Jominy's hardenability test in brief. 6
(c) explain various mechanisms of hardening in metals and alloys. 6
six (a) discuss the working principle of a bimetallic strip thermostat in regulating
temperature. 5
(b) describe thermal stress. explain stresses due to restrained thermal expansion and
contraction. 5
(c) describe high temperature materials. Name a few of the high temperature materials. 5
(d) elaborate ceramics? What is the range of thermal expansion coefficients in ceramics?
discuss why ceramics have low coefficient of thermal expansion. 5
7. (a) elaborate polymers? define briefly the terms 'saturated polymer' and 'unsaturated
polymer'. 8
(b) Differentiate ranging from thermoplastic and thermosetting polymers 6
(c) describe the term 'composites'. define briefly about various kinds of composites and
their applications. 6
8. (a) elaborate nano materials? Mention important applications of nano materials 8
(b) describe Curie temperature. What is spontaneous magnetisation? Write about
characteristics of ferromagnetic materials 6
(c) explain band theory of solids. Differentiate ranging from metals, semiconductors, and
insulators on the basis of band theory. 6
Group C
9. ans the subsequent in brief: l0 × 2
(i) At high temperature, the mechanical strength is high or low? provide ans with proper
reasoning.
(ii) Draw the binary phase diagram of Al2O3— Cr2O3 clearly showing the tie line.
(iii) Why thoria dispersed nickel retains very good mechanical strength up to 0.9 Tm , where
Tm is its melting point ?
(iv) Mention relative magnitudes of enthalpy of motion for the atoms moving on the surface
along the boundary and within the lattice.
(v) discuss how surface cracks can be made ineffective.
(vi) obtain the fractional amount of ferrite (a) and cementite (Fe3C) using Lever's rule and
placing the fulcrum at 0.8% carbon in iron—iron carbide phase diagram.
(vii) What is glass? Mention its important characteristics.
(viii) discuss the degree of polymerisation
(ix) Draw schematics of (a) linear, (b) branched, (c) cross-linked, and (d) networked polymer
structures.
(x) Define (a ) susceptibility, (b ) permeability, and (c) magnetisation of a magnetic
material..
Summer 2005 : AN 202/AD 302 MATERIAL SCIENCE AND ENGINEERING
Time : Three hours Maximum marks : 100
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.
Group A
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 a - 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.
(b) Explain with reasons: 2x5
(i) Ceramics are very hard
(ii) Solar dells are semiconductors with p-n junctions
(iii) High tdmperatufe creep is a diffusion controlled process
(iv) Brittle fracture commonly occurs in Grey Cast Iron
(v) Brass is always stronger than copper at room temperature.
Group B
5. (a) (i) Why has ferrite very low solubility of carbon, while austenite has high
solubility of carbon ? 2
(ii) What is Hardenability ? Why is it not so high in plain carbon steels? ;2+2
(iii) Draw the Peritectic reaction of Fe-C system. 2
(b) (i) State the advantages of Normalising over Annealing. 2
(ii) What is Critical Cooling Rate? Why is the shape of the T-T-T diagram in form of English letter 'C ? 2+2
(iii) What is Tempering ? Is it essential for high carbon steel after quenching?
2
(iv) Write the scientific names of following polymers with one of their typical use: Teflon, ABS. 2x2
6. (a) Explain a Chain Polymerisation, reaction. What is the Degree of
Polymerisation ?
If a particular type of polyethylene has a molecu -lar mass of 140,000 g/mol, what Is its degree of polymerisation? 2+2+2
(b) Distinguish between Homopolymer and Copolymer. 2x 2
State the basic structural units of PMMA and Nylon 6,6, elaborating their properties. (2x2) + (2xl)
( c) Define a Semiconductor and a Transistor. 2+2
7. (a) Differentiate between Ceramics and Glass, with examples. What is the Glass Transition Temperature? What type of glass is used in spectacle lenses?
(2x2)+ 2
(b) Explain the reasons for the rising popularity of Pure Oxide Ceramics over traditional refractories. What is Magcarb? Where is it commonly being used?
2+2
(c) Draw the crystallographic unit of Si O4 ion. What is Mullite? Explain Slip
Casting. 2+(2+2)
(d) What is Alnico? Explain Patenting. 2+2
8. (a) (i) Why are monovalent metals like Silver or Copper so conductive? 2
(ii) Discuss Dielectric Constant and Dielectric Strength for ceramics. 2+2
(iii) Name two important ceramic insulators with their properties. 2
(b) (i) What is Hysteresis Loop? Explain its importance.
(ii) Distinguish between Diamagnetism and Paramagnetism. (2+2) +2
(c) What is E-glass? Where is it commonly used? 2+2
(d) By Energy Band Model explain the electrical conduction of an Intrinsic Semiconductor. 2
Group C
9. Answer the following: 2x10
(i) A tension test recorded ah engineering strain of 00046 against the engineering stress of 345 MPa of a material within its elastic range. Find out the elastic modulus of the material and the type of metallic alloy (like iron base, copper base etc)
(ii) The final thickness of a hard copper sheet is 1.0 mm. It was produced by cold working with 2.5% deformation. What was the starting thickness of the metal before cold working? To decrease the hardness what will you do?.
(iii) Atomic radii of two metal atoms are 0.128 nm and 0.133 nm respectively. Find out whether they form a solid solution, and if they form, state what type of solid solution it is.
(iv) Write down the Slip Plane and Slip Direction (one plane and one direction only) of Nickel (only Miller indices). How many slip systems are there in Nickel?
(v) Brass has a peritectic reaction at a temperature of 9030C with 36.8% Zn ((phase) in the middle and 32-5% Zn at a-phase end and 37-5% Zn at liquidus end. Find out the percentages of liquid phase and a -phase present at the peritectic point.
(vi) Calculate the degree of freedom for eutectic reaction for an iron-carbon alloy and an iron-chromium-nickel alloy, under 1 atmosphere.
(vii) State the crystal structures of Cementite and Martensite.
(viii) The fracture toughness equation of a material is given by Kfc= afy[m . If the
material has a strength of 300 MPa, and a fracture toughness of 4 MPa 4m , find out the largest internal crack in microns the material will support without cracking. uf = strength MPa, a = Crack size, m.
(ix) Name two soft magnetic materials.
(x) Write the scientific names of PET and Melamine.
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