B.
Tech/ME/3d Sem/MECH-21 04/201 5
iv) The cause of hydrogen bonding is
(a) dipole bonding (b) Vander Waal's bonding
(c) lonic bond (d) both (b) & (c)
B.Tech/ME/3"d Sem/MECH-21 O4t2O1 5
v) Which of the following is magnetic allotrope of iron?
2015 (a) cr-iron (b) p-iron
ENGINEERING MATERIALS (c) y-iron (d) 5-iron
(MECH2104) vi) 'a' is the laftice parameter of a BOC crystal, the distance
Time A oted : 3 Hours Full Marks : l0 between two nearest neighbours are
Figures out of the right margin indicate full marks. -. r5
(a) (b) 2a
Candidates are required to answer Group A and anv S (five) z^a
from Group B to E, taking at least one from each group.
Candidates are required to give answer in their own words " ^tE
tct (d) J,
as far as practicable J
-
vii) An increase in the percentage of carbon results into
GROUP - A decrease in its
(Multiple Choice Type Questions)
(a) Hardness (b) Ductility
1. Choose the correct alternatives for the following : [10x1=10J (c) Ultimate strength (d) Corrosion resistance
i) Which of the following bonds is the weakest? viii) The equation n = 2dsino represents
(a) lonic bond (b) Covalent bond (a) Bragg's law (b) Miller indices
(c) Metallic bond (d) Secondary di-pole bond (c) Atomic packing factor (d) none of these
ii) Gibbs phase rule for condensed state reaction under ix) Crystal structure is studied by
conslant pressure is (a) Metallographic technique
(a) F+P = C+2 (b) F+C = P+t (b) X-ray technique
(c) F+P = C+1 (d) F+1 = C+P (c) Ultrasonic method
iii) Magnesium present in the alloy steel increases the (d) Electron microscopy
property of
x) Pearlite is a mixture of cementite and
(a) Ductility (b) Hardness
(a) Ferrite (b) Austenite
(c) Toughness (d) Britleness
(c) Bainite (d) Mertensite
MECH 2104 I Turn over I MECH2104 2 lTurn overl
B.Tech/ME/3d Sem/MECH_21 04/201 s B.Tech/ME/3rd Sem/MECH-21 0,U201 5
GROUP - B (b) Distinguish between ductile fracture and brinnel fracture.
2 (a) Mention the differences between the slip and
twinning 6+6 = '12
mechanism for plastic deformation of metals.
(b) With the help of neat sketches, explain how
7. (a) ln order to evaluate various mechanical properties of a
the slip steel specimen of 12.5 mm diameter and 62.d mm gauge
occurs by the movement of edge dislocation. length was tested in a standard tension test. yetj
toaO
6+6 = 12 = 40.0 KN; Maximum load = 71.5 KN; Fracture load =
3 (a) Discuss the major differences betlveen lonic
bonding,
50.5 KN; Gauge length at fracture = 79.5mm; strain at
load of 20 KN = 7.75 x10{. Determine : (i) modulus
Covalent bonding & Metallic bonding of
elasticity, (ii) Modutus of resitience, (iiij Modulus of
(b) What do you mean by point defects? Name their types toughness.
with the corresponding sketches. 6+5 = 12
(b) A fatigue test was conducted in which the mean stress
GROUP - C was 70 Mpa and the stress amplitude was 210 Mpa.
4. (a) Name any two non-ferrous alloys mentioning their Compute the following : (i) The maximum and minimum
stress levels, (ii) Stress ratio, (iii) Stress range, (iv) The
compositions, properties and applications.
total stress. 5+6 12
(b) Write short notes of (i) TTT Curves, (ii) Age =
Hardening GROUP. E
heat treatment, (iii) Normalising. 6+6 = 12
8. (a) Distinguish between thermoplastics & thermo setting
5. (a) Draw an iron carbon phase diagram showing eutectoid, plastics using any three of their characteristics.
eutectic and peritectic points wlth all the temperatures
and carbon percentages. (b) Mention the general properties of the polymeric
(b) What is carburizing? Why is it necessary to materials. What are the major applications of elastomers?
harden and
temper the component after carburizing. 6+6 = 12 6+6 = 12
Group - D
9. (a) Define corrosion and discuss types of corrosion usually
encountered.
6(a) Define brinnel hardness number and from definition show
that brinnel no N is given by (b) What do you understand by (i) Season cracking of Brass,
(ii) caustic embritflement of boiler plate. 6+6 = 12
N=
---g-
10* - 100 d2
where diameter of steel ball is 1Omm, the load is 300okg
and diameter of impression is d. What would be th6
corresponding formula for 10mm ball and 500kg load?
MECH 2104
I Turn over J MECH 2104
