Material Science & Metallurgy - May 2016
Mechanical Engineering (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.
1(a) Which one of the following is not basic component of Matrials science? _______ .
(a) Cost (b) Properties (c) Structure (d) Performance(1 marks) 1(b) Strong and ductile materials
(a) Polymers (b) Ceramics (c) Metals (d) Semiconductors(1 marks) 1(c) An eutectoid steel consists of _______ .
(a) Wholly Pearlite (b) Wholly austenite (c) Pearlite and ferrite (d) Pearlite and cementite(1 marks) 1(d) The hardness and tensile strength in austentic stainless steel can be increased by _______ .
(a) Hardening and cold working (b) normalising (c) martempering (d) Full annealing(1 marks) 1(e) Iron-carbon alloys containing 1.7 to 4.3% carbon are known as
(a) eutectic cast irons (b) hypo-eutectic cast irons (c) hyper-eutectic cast irons (d) none of these(1 marks) 1(f) The heat treatment process used for softening hardened steel is _______
(a) Carburising (b) Normalising (c) annealing (d) tempering(1 marks) 1(g) The typeof space lattice found in gama-iron is _______
(a) FCC (b) BCC (c) HCP (d) none of these(1 marks) 1(h) Which of the following is a point imperfection? _______
(a) Vacancy (b) Interstitial imperfection (c) Frenkel imperfection (d) none of these(1 marks) 1(i) Micro-structure of a material is generally, examined by _______
(a) naked eye (b) optical microscope (c) X-ray techniques (d) none of these(1 marks) 1(j) In a unit cell of a body centred cubic space lattice, there are _______ number of effective atoms.
(a) 2 (b) 9 (c) 1 (d) 4(1 marks) 1(k) Silicon is added in low carbon steels to _______
(a) Make the steel tougher and harder (b) make the steel of good bending qualities (c) raise the yield point (d) all of these.(1 marks) 1(l) The compressive strength of Cast Iron is _______ that of its Tensile strength.
(a) Equal to (b) less than (c) more than(1 marks) 1(m) The ratio of the volumeoccuiped by the atoms to the total volume of the unit cell is called _______ .
(a) Coordination number (b) atomic packing factor (c) space lattice (d) none of these(1 marks) 1(n) Wrought iron _______ .
(a) is a ductile material (b) can be easily forged or welded (c) cannot stand sudden and excessive shocks (d) all of these(1 marks) 2(a) Classify the engineering materials. Explain any two of them.(3 marks) 2(b) Differentiate between Edge and Screw dislocation.(4 marks)
Solve any one question from Q.2(c) & Q.2(d)
2(c) Explain in detail, the solidification of an ingot/casting giving sketches of all important zones produced as a structure of ingot/casting.(7 marks) 2(d) What is twinning deformation? Explain the difference between slip and twinning mechanisms using sketch.(7 marks)
Solve any three question from Q.3(a), Q.3(b), Q.3(c) & Q.3(d), Q.3(e), Q.3(f)
3(a) Explain the phenomenon of 'Allotropy' by giving a suitable example.(3 marks) 3(b) Draw a unit cell and show the following planes (a) (113) (b) (102) (c) (111) and (d) (001).(4 marks) 3(c) Differentiate between Micro and Macro examination of engineering metallic materials? Completely describe the procedure for 'specimen preparation for microscopic examination'.(7 marks) 3(d) State the 'Gibbs phase rule'. Using this rule prove that degree of freedom at eutectic point in a binary phase diagram is zero.(3 marks) 3(e) What is the metallurgical explanation of effects of chromium, nickel, molybdenum, and carbon in stainless steels?(4 marks) 3(f) Differentiate between Homogeneous and Heterogeneous nucleation processes. Also discuss the conditions under which growth may be of planar and dendritic type.(7 marks)
Solve any three question from Q.4(a), Q.4(b), Q.4(c) & Q.4(d), Q.4(e), Q.4(f)
4(a) Draw the microstructure of white cast iron and enlist its properties.(3 marks) 4(b) Enlist methods of manufacturing metal powder. Describe any one in detail.(4 marks) 4(c) Evaluate: Annealing is never a final heat treatment process for hypereutectoid steel. Compare and contrast the Annealing with Normalizing process.(7 marks) 4(d) State critical reactions of Iron Carbon phase diagram.(3 marks) 4(e) What is Alloying? Explain the effects of chromium as an alloying element.(4 marks) 4(f) Justify the need of Heat treatment processes for metals. Explain with neat sketch TTT diagram for heat treatment of steel.(7 marks)
Solve any three question from Q.5(a), Q.5(b), Q.5(c) & Q.5(d), Q.5(e), Q.5(f)
5(a) List various nondestructive tests. Explain general advantages and disadvantages of non-destructive tests.(3 marks) 5(b) Explain the phenomenon of 'Coring'.(4 marks) 5(c) Define Powder Metallurgy. State advantages, limitations and applications of Powder Metallurgy.(7 marks) 5(d) Explain following alloys giving their important constituents & Applications : (I) Monel (II) Invar (III) Nichrome.(3 marks) 5(e) Completely describe the 'Sintering Process'.(4 marks) 5(f) Explain the Eddy current Method of Testing with neat sketch. Also explain its benefits and limitations.(7 marks)