81
Which of the following manufacturing processes is not used for producing fine grained metals?
A)
Electrodeposition
B)
Czochralski method
C)
Equi-Channel Angular Pressing (ECAP)
D)
Sintering of milled powders
Answer & Solution
Answer: Option
B
82
In the eutectoid steel, which one of the following structures does not form during continuous cooling?
A)
Fully pearlitic
B)
Pearlitic + bainitic
C)
Fully bainitic
D)
Martensitic
Answer & Solution
Answer: Option
C
83
Spheroidal graphite is obtained incast irons by
A)
inoculating the melt with ferrosilicon
B)
adding nickel to the melt in the form of round shots
C)
treating the melts of controlled compositions with magnesium
D)
annealing of flake graphite cast iron
Answer & Solution
Answer: Option
A
84
Martensite in steels is
A)
an interstitial solid solution of C in alpha iron
B)
a supersaturated interstitial solution of C in BCT iron
C)
a supersaturated solid solution of C in gamma iron
D)
a very finely dispersed lamellar structure
Answer & Solution
Answer: Option
B
85
Match the desired mechanical properties listed in
Group I with the microstructural features listed in
Group II .
Group I Group II
P. Creep resistance
1. Fine grained two-phase microstructure
Q. Elastic modulus enhancement
2. Single crystal
R. Superplasticity
3. Coherent precipitates
S. Increased strength
4. Glass fibres in epoxy
A)
P-3, Q-4, R-2, S-1
B)
P-1, Q-2, R-3, S-4
C)
P-2, Q-4, R-1, S-3
D)
P-1, Q-4, R-2, S-3
Answer & Solution
Answer: Option
C
86
Other parameters remammg same, the recrystallisation temperature of an alloy is lowered, when
A)
strain rate is increased
B)
grain size is increased
C)
prior cold deformation is increased
D)
not affected by any of the above parameters
Answer & Solution
Answer: Option
A
87
Match the following.
Group-I Group-II
P. Hardness of martensite in steels
1. Extent of cold working
Q. Hardness of pearlite in steels
2. Particle size of the resulting carbide
R. Hardness of tempered martensite in steels
3. Interlamellar spacing
S. Hardness of α° brasses
4. Weight per cent of carbon
A)
P-4, Q-3, R-1, S-2
B)
P-4, Q-3, R-2, S-1
C)
P-3, Q-4, R-1, S-2
D)
P-1, Q-2, R-3, S-4
Answer & Solution
Answer: Option
B
88
Driving force for grain growth after completion of recrystallisation is
A)
stored energy of cold work
B)
vacancy concentration
C)
dislocation density in the crystal
D)
grain boundary curvature
Answer & Solution
Answer: Option
D
89
In an Ellingham diagram, the standard free energy change ΔG° for the oxidation reaction of a metal M given by : xM(s) + O2 (g) ⟶ MxO2 (s), is plotted as a function of temperature. The slope of this line is positive because
A)
ΔS° is positive
B)
ΔS° is negative
C)
ΔH° is positive
D)
ΔH° is negative
Answer & Solution
Answer: Option
B
90
Example/examples of eutectoid system is/are
A)
Ag-Cd, Ag-Ga, Pb-Sn
B)
Ag-Cd, Ag-Ga, Al-Mn, Bi-Cd
C)
Ag-Cd, Ag-Ga, Al-Mn, Au-Zn, Pb-Sn
D)
Ag-Cd, Ag-Ga, Al-Mn, Au-Zn, Cu-Zn, Cu-Sn
Answer & Solution
Answer: Option
D
