Physical Metallurgy MCQ Questions and Answers

91

If d is the inter-planar spacing of the planes {h k I}, the inter-planar spacing of the planes {nh nk nl}, n being an interger, is

A) d B) $$\frac{d}{n}$$ C) nd D) $$\frac{d}{{{n^2}}}$$

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Answer & Solution

Answer: Option B

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92

Which one of the following elements is an austenite stabilizer?

A) Nitrogen B) Molybdenum C) Vanadium D) Tungsten

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Answer & Solution

Answer: Option A

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93

In the Ellingham diagram for oxides, C-CO line cuts the M-MO line at temperature T₁ and the M'-M'O line at a higher temperature T₂. At a temperature greater than T₁ and less than T₂, carbon can reduce

A) MO B) both MO and M'O C) M'O D) neither MO nor M'O

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Answer & Solution

Answer: Option D

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94

Match the microstructural state of the following steels with. their respective heat treatments

Group-I	Group-II
P. Eutectoid steel homogenised at 900°C and quenched in water at room temperature	1. Ferrite, martensite and retained austenite
Q. A 0.4% C steel soaked at 750°C and quenched in water at room temperature.	2. Pearlite and carbide
R. Normalised 1%C steel.	3. Martensite and retained austenite
S. Eutectoid steel subjected to normalising	4. Pearlite

A) P-4, Q-3, R-1, S-2 B) P-3, Q-4, R-2, S-1 C) P-4, Q-3, R-2, S-1 D) P-1, Q-2, R-4, S-3

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Answer & Solution

Answer: Option C

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95

For the same volume fraction, size and size distribution of precipitates, the highest strength in a precipitation-hardened material is obtained when the precipitates are

A) uniformly distributed in annealed matrix B) distributed along grain boundaries C) nucleated on dislocation substructure D) nucleated at impurities and inclusions

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Answer & Solution

Answer: Option C

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96

In the homogenous nucleation, as compared to heterogeneous nucleation

A) undercooling is more and the critical radius of the spherical surface of the nucleus r_cr is smaller B) undercooling is more and r_cr is larger C) undercooling is smaller and r_cr is smaller D) undercooling is smaller and r_cr is larger

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Answer & Solution

Answer: Option A

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97

Choose the correct statements.
P. Interstitial atoms diffuse slower than substitutional atoms
Q. In pure metals the vacancy concentration increases with temperature
R. Martensitic transformation is athermal in nature
S. Atoms in the grain boundary diffuse slower than in the bulk at relatively lower temperatures.

A) P, Q B) Q, R C) Q, S D) R, S

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Answer & Solution

Answer: Option B

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98

During load Vs load-line displacement measurement for the determination of J₁₀ conipliance is measured at intervals to estimate

A) strain energy B) crack radius C) crack length D) crack opening displacement

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Answer & Solution

Answer: Option D

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99

A defect that is bounded by two mirror planes is

A) twin B) stacking fault C) grain boundary D) edge dislocation

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Answer & Solution

Answer: Option A

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100

The growth rate of pearlite, v, and the interlamellar spacing S are given by the following relation, $$v = k.\frac{1}{S}\left( {\frac{{1 - {S_c}}}{S}} \right)$$ where S_c is the critical spacing at which the growth rate is zero and k is a materials constant. The actual interlamellar spacing observed will correspond to

A) S = S_c B) S = 2S_c C) S = 3S_c D) S = S_c²

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Answer & Solution

Answer: Option A

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Physical Metallurgy MCQ Questions and Answers | Metallurgical Engineering