Physical Metallurgy MCQ Questions and Answers

21

A 10 mm thick En-24 steel yielded a valid plane strain fracture toughness of 80 Mpa √m. The minimum yield strength of the steel is . . . . . . . . MPa.

A) 40 B) 1265 C) 1000 D) 126.5

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Answer & Solution

Answer: Option B

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22

In precipitation hardenable alloy like duralumin, intermediate precipitates can form due to

A) difficulty of nucleation of the final precipitate B) difficulty of the growth of the final precipitate C) ease of diffusion D) coherency strain

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Answer & Solution

Answer: Option D

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23

Identify the incorrect statement with respect to grain growth.

A) As the average grain size increases, the grain boundary energy per unit area deceases B) The driving force for grain growth is the decrease in grain boundary energy per unit volume of the material C) Higherthe temperature, the faster is the grain growth D) Impurity atoms segregated at grain boundaries can retard grain growth

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Answer & Solution

Answer: Option A

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24

Coring is often being removed by subsequent

A) Annealing process B) Homogenization process C) Hot working process D) All are correct

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Answer & Solution

Answer: Option D

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25

During the solidification of a pure metal, it was found that dendrites are formed. Assuming that the liquid-solid interface is at the melting temperature, the temperature from the interface into the liquid

A) Decreases B) Increases C) Remains constant D) Increases and then decreases

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Answer & Solution

Answer: Option A

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26

Creep resistance decreases due to

A) Small grain size B) Fine dispersoid size C) Low stacking fault energy D) High melting point

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Answer & Solution

Answer: Option A

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27

What is the eutectic composition in Pb-Sn diagram

A) 39.1% Pb and 60.9% Sn B) 34.1% Pb and 65.9% Sn C) 38.1% Pb and 61.9% Sn D) 39.9% Pb and 64.1% Sn

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Answer & Solution

Answer: Option C

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28

The net effect of continuous cooling on the TTT curves is that the curves are shifted to the

A) right and lowered B) left and lowered C) right and raised D) left and raised

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Answer & Solution

Answer: Option C

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29

Substantial amount of bainite can form during continous cooling in

A) unalloyed low carbon steel B) unalloyed high carbon steel C) alloy steel D) none of these

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Answer & Solution

Answer: Option C

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30

A 0.2% C steel is equilibriated just above the eutectoid temperature and then quenched in iced brine. The room temperature microstructure will consist of

A) 77% ferrite and 23% martensite B) 76% ferrite and 24% pearlite C) 60% ferrite and 40% martensite D) 97% ferrite and 3% pearlite

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Answer & Solution

Answer: Option B

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Physical Metallurgy MCQ Questions and Answers | Metallurgical Engineering