Physical Metallurgy MCQs with Answers 2027

Q41

Match the names in Group 1 with invarient reactions in binary phase diagram in Group 2.

Group 1	Group 2
P. Eutectic	1. S₁ = S₂ + S₃
Q. Eutectoid	2. L = S₁ + S₂
R. Peritectoid	3. L₁ = L₂ + S
S. Monotectic	4. S₁ + S₂ = S₃

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Q42

Open question

Assume that Sievert's law holds for solubility of hydrogen dissolved in a thin metal foil. If the partial pressure of hydrogen in contact with the foil is increased by a factor of 4, the solubility increases by a factor of

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Q43

Open question

Match the heat treatment processes of steel in Group 1 with the microstructural features in Group 2.

Group 1	Group 2
P. Quenching	1. Bainite
Q. Maraging	2. Martensite
R. Tempering	3. Internietallic precipitates
S. Austempering	4. Epsilon carbide

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Q44

Open question

The free energy change during melting of ice at 0°C is equal to

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Q45

Open question

At which temperature, cementite changes ferromagnetic to paramagnetic character in iron carbon diagram

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Q46

Open question

The elastic strain energy of a unit length of an edge dislocation as compared to that of a screw dislocation is

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Q47

Open question

The peritectic reaction in binary systems is given by

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Q48

Open question

The critical nucleus size (in mm) when copper melt is under-cooled by 100K is
Given data:
Melting point: 1356 K
Density: 8900 kg.m^-3
Solid-liquid interfacial energy: 0.5 Jm^-2
Latent heat of freezing: 13000 J. mol^-1
Molar volume: 7 × 10^-6 m³ mol^-1

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Q49

Open question

Which of the following is true for martensitic transformation in steels?

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Q50

Open question

If the interfacial energy is increase by 10%, the homogeneous nucleation barrier for a spherical particle increases by

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Q51

Open question

A number of solid state phase transformations follow a sigmoidal pattern. In these eases, at any time the fraction transformed can be expressed as

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Q52

Open question

From an alloy, two specimens are machined and tested separately under tension and compression. The engineering stress-strain curves as well as the true stress-true strain curves for tension and compression are plotted in the same diagram. Identify the correct statements:
P. The engineering stress-strain curves in tension and compression are identical.
Q. The true stress-true strain curve in compression is lower than the true stresstrue strain curve in tension due to Bauschinger effect.
R. The true stress-true strain curve in tension is above the corresponding engineering stress-strain, curve.
S. The true stress-true strain curve in tension and compression are identical.

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Q53

Open question

Which one of the following is a ferrite stabiliser in steels?

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Q54

Open question

In Cu-Al phase diagram, the solubility of Al in Cu at room temperature is about 10% and that of Cu in Al is less than 1%. The Hume-Rothery rule that justifies this difference is

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Q55

Open question

The property of a material that cannot be significantly changed by heat treatment is

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Q56

Open question

A binary phase diagram of components P and Q displays an eutectoid reaction with terminal solid solutions a on the P rich side and β on the Q rich side. At the eutectoid temperature, the solubilities of Q in a and β are 5 and 90 wt% respectively. The densities of α and β phases are 9.5 and 2.49 gm/cm³ respectively.
At the eutectoid point, the alloy has α and β in the weight ratio 1 : 1. The eutectoid point occurs at composition . . . . . . . . wt % Q.

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Q57

Open question

Match the elements is Group I with their corresponding crystal structures in Group II.

Group I	Group II
P. Tungsten	1. HCP
Q. Nickel	2. Simple cubic
R. Magnesium	3. BCC
S. Polonium	4. FCC

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Q58

Open question

Match each phase in Group 1 with a description in Group 2.

Group 1	Group 2
P. E-carbide	1. A three component eutectic of iron, iron carbide, iron phosphate found in cast iron
Q. Sigma phase	2. An embrittling compound found in ferritic stainless steel
R. E-ferrite	3. Obtained on tempering of hardened steels
S. Steadite	4. Responsible for causing the weld deposit on austenitic stainless steels to be slightly magnetic

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Q59

Open question

A liquid phase sintered SiC-Ni composite has a solid-solid grain boundary energy (γ_SiC-SiC) of 0.80 J.M^-2 and a solid-liquid (γ_SiC-SiC) interfacial energy of 0.45 J.m^-2. For a SiC grain size of 20 μm, the average interparticle (SiC-SiC) neck size (in μm) is:

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Q60

Open question

If the slip direction is at right angle to the tensile axis, then the value of critical resolve shear stress is

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