Metallurgical Engineering Gate Yearwise 



Metallurgical Engineering Gate 2020 Questions with Answer

Ques 40 GATE 2020

Match the materials in Column I with their common applications in Column II.

A

P-1, Q-3, R-2, S-4

B

P-4, Q-2, R-1, S-3

C

P-2, Q-1, R-4, S-3

D

P-2, Q-3, R-1, S-4


(d) is the correct answer.

Ques 41 GATE 2020

The Mg-Sn phase diagram exhibits two eutectics on either side of the high melting intermetallic line compound, Mg2Sn, as given below.
At 561oC: L (36.9 wt.% Sn) → α (14.48 wt.% Sn) + Mg2Sn
At 203oC: L (97.87 wt.% Sn) → β-Sn (almost 100 wt.% Sn) + Mg2Sn
After the eutectic reaction has gone to completion and equilibrium has been attained at a temperature just below 561oC, the amount of eutectic constituent (in wt.%) present in the alloy, Mg-50 wt.% Sn, is approximately _______. Given, atomic weight of Sn is 118.7 and Mg is 24.3.
(A) 25
(B) 38
(C) 62
(D) 75

A

25

B

38

C

62

D

75


(c) is the correct answer.

Ques 42 GATE 2020

Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]
Assertion [a]: Low-alloy steels used for medium-temperature creep resistance often have additions of strong carbide-forming elements.
Reason [r]: During creep deformation, the particles with higher misfit with the matrix, lose coherency.

A

Both [a] and [r] are true and [r] is the correct reason for [a].

B

Both [a] and [r] are true but [r] is not the correct reason for [a].

C

Both [a] and [r] are false.

D

[a] is true but [r] is false.


(b) is the correct answer.

Ques 43 GATE 2020

Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]
Assertion [a]: The rate of homogenization in a dilute substitutional solid solution of B in A is controlled by the diffusivity of B.
Reason [r]: Atomic migration cannot occur along dislocations and grain boundaries.

A

Both [a] and [r] are true and [r] is the correct reason for [a]

B

Both [a] and [r] are true but [r] is not the correct reason for [a]

C

Both [a] and [r] are false

D

[a] is true but [r] is false


(d) is the correct answer.

Ques 44 GATE 2020

Match the elements in Column I with their electronic behaviour given in Column II.

A

P-1, Q-2, R-3, S-4

B

P-3, Q-4, R-1, S-2

C

P-4, Q-1, R-2, S-3

D

P-4, Q-3, R-1, S-2


(c) is the correct answer.

Ques 45 GATE 2020

Radius of the largest interstitial atom that can be accommodated in an octahedral void in BCC iron without distorting the lattice is _______ nm (round off to three decimal places).
Assume hard sphere model and radius of Fe atom as 0.124 nm.


(0.019) is the correct answer.

Ques 46 GATE 2020

A metal oxidizes at 1200 K with a parabolic rate constant of 3 × 10-6 g2⋅cm-4⋅s-1. Time taken for the oxide film to grow to a thickness of 2 µm is _______ s (round off to two decimal places). Given, density of oxide is 6.5 g⋅cm-3.


(0.55) is the correct answer.

Ques 47 GATE 2020

Two plates of composition, Fe-10 wt.% Ni and Fe-20 wt.% Cr-5 wt.% Ni are fusion-welded using a filler rod of composition 20 wt.% Ni-80 wt.% Cr. Contribution to dilution of the weld pool is 20% from each plate. The Ni content in the weld pool is _______ wt.% (round off to the nearest integer).


(15) is the correct answer.

Ques 48 GATE 2020

1000 kg of liquid steel containing 0.03 wt.% S needs to be desulphurized using a slag to bring the sulphur content down to 0.015 wt.%. The quantity of slag needed is _______ kg (round off to the nearest integer).
Assume:
1. Thermodynamic equilibrium
2. No sulphur in the slag prior to desulphurization treatment Given the equilibrium sulphur partition ratio between slag and steel,
((wt.%S)in slag) / ([wt.%S]in steel) is 50.


(20) is the correct answer.

Ques 49 GATE 2020

Zone refining of Si results in residual P content of 0.1 parts per billion by weight. The electrical conductivity of this zone refined Si is _______ Ω⁻¹⋅m⁻¹ (round off to two decimal places).
Given:
1. Avogadro number is 6.02 × 10²³.
2. Density of Si is 2.33 g⋅cm⁻³
3. Atomic weight of P is 30.97.
4. Charge of electron is 1.6 × 10⁻¹⁹ A⋅s
5. Mobility of electron is 0.2 m²⋅V⁻¹⋅s⁻¹


(0.15) is the correct answer.

Ques 50 GATE 2020

The steady state creep rate of a material increases by a factor of 20 when the temperature is increased from 890 K to 980 K. The creep rate at a temperature of _______ K (round off to the nearest integer) will be 5 times the creep rate at 890 K.


(935) is the correct answer.

Ques 51 GATE 2020

Crack growth is being continuously measured in a test specimen subjected to constant amplitude cyclic stress with a mean stress of zero. The crack growth rate is related to the stress intensity range, ΔK as
da / dN ∝ (ΔK)³,
where, a is the crack length and N is the number of cycles. When the crack length increases by a factor of two, the crack growth rate will increase by a factor of _______ (round off to one decimal place).


(2.8) is the correct answer.

Ques 52 GATE 2020

Figure shows schematic of a venturimeter. The cross sectional area is 100 mm² at A and is 50 mm² at B. If air is flowing through the venturimeter at a flow rate of 10⁻³ m³⋅s⁻¹, the height H in the air-over-water manometer is _______ mm (round off to the nearest integer).
Assume:
1. Incompressible flow with no friction losses.
2. Density of air is 1 kg⋅m⁻³.
3. Density of water is 1000 kg⋅m⁻³
4. Acceleration due to gravity is 9.8 m⋅s⁻².


(15) is the correct answer.

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