Physical Metallurgy MCQs with Answers 2027

Q121

Match the names listed in Group I with the reactions listed in Group II.

Group I	Group II
P. Eutectic	1. γ + β ⟶ α
Q. Peritectic	2. L ⟶ α + β
R. Peritectoid	3. L₁ ⟶ L₂ + α
S. Monotectic	4. L + β ⟶ α

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Q122

Open question

Pb-Sn is an example

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Q123

Open question

Atomic packing factor of BCC crystal structure is

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Q124

Open question

Identify the attributes associated with dispersion hardened alloys.
P. Dispersoids do no dissolve in the matrix even at high temperature.
Q. Dispersoids are coherent with the matrix.
R. Dispersoids impart creep resistance to the alloy.
S. Dispersoids improve the corrosion resistance of the alloy.

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Q125

Open question

Internal cracks in drawn bars are due to

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Q126

Open question

Von Mises criterion for plastic yielding of a ductile metal predicts that the yield stress in uniaxial tension is related to that in pure torsion as

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Q127

Open question

During decarburising of a plane carbon steel, the thickness of ferrite layer growth is proportional to

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Q128

Open question

A steel specimen containing 0.2 wt.% C is carburized in an atmosphere that maintains a carbon content of 1.2 wt.% C at the surface of the specimen.
Given:
For carbon diffusion in austenite: D₀ = 2.0 × 10^-5 m²/s
Activation energy for diffusion, Q = 142 kj/mol

y	erf(y)
0.85	0.7707
0.90	0.7970
0.95	0.8209

What is the depth (in (μm) from the surface of the specimen at which a composition of 0.4wt.% C is obtained after carburizing at 870°C for 10 h?

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Q129

Open question

The plane strain fracture toughness (K_IC) and yield strength of a material are

100 M N^{- \frac{3}{2}} m

and 500 MN^-2m respectively. The minimum plate thickness to determine K_IC is . . . . . . . . cm.

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Q130

Open question

Gold has surface free energy of 1.5 J.m^-2 and grain boundary energy of 0.365 J.m^-2. The groove angle that forms where a grain boundary intersects the free surface in a well annealed sample is

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Q131

Open question

Match the scientist pairs listed in Group I with phenomena listed in Group II.

Group I	Group II
P. Hall-Patch	1. Dislocation reaction product
Q. Nabarro-Herring	2. Diffusional creep
R. Lomer-Cottrell	3. Dislocation source
S. Frank-Read Group	4. Grain boundary strengthening

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Q132

Open question

The diffusion couple shown below is made from two A-B alloys. The initial compositions of the two alloys are indicated in the diagram. The centreline is at x = 0. The couple is held at an elevated temperature for 40 hours. Diffusivity; D = 3 × 10^-11 m^-2 s^-1. Assume the diffusion couple to be infinitely long.
Physical Metallurgy mcq question image

Which of the parameters give the composition profile in the following form?

C (x, t) + c_{1} + c_{2} er f (\frac{1}{2 D t})

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Q133

Open question

In order to double its yield strength, the grain size of a steel of ASTM grain size number 2 should be changed to ASTM grain size number (neglect friction stress)

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Q134

Open question

Ratio of tetrahedral to octahedral voids in FCC

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Q135

Open question

The effective number of lattice points in the unit cell of end centered monoclinic lattice is

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Q136

Open question

Which of the following phenomenon/phenomena is/are diffusion controlled?

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Q137

Open question

Maraging steels derive their strength from the following mechanism:

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Q138

Open question

Yield strength ofapolycrystalline metal with an average grain size, d, is proportional to

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Q139

Open question

Under application of stress, when a straight dislocation (radius of curvature, r = ∞) tries to bow out around precipitates of spacing L, there is an instability during changing of curvature at

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Q140

Open question

Which one of the following is an equilibrium defect?

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