Material Science MCQ Set 7
MATERIAL SCIENCE MCQ SET 7
Q1. Which material is most suitable for high-temperature furnace linings?
A) Aluminum
B) Refractory ceramics
C) Mild steel
D) Copper
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Answer: B) Refractory ceramics
Explanation: Refractories resist high temperature and thermal shock, making them ideal for furnaces.
Q2. Quenching steel in water rather than oil results in:
A) Slower cooling
B) Faster cooling
C) No change in cooling rate
D) Reduced hardness
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Answer: B) Faster cooling
Explanation: Water has higher heat capacity and thermal conductivity, producing faster cooling.
Q3. Which property of metals increases with grain refinement?
A) Ductility
B) Yield strength
C) Thermal expansion
D) Electrical conductivity
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Answer: B) Yield strength
Explanation: Hall-Petch relation: finer grains impede dislocation motion, increasing strength.
Q4. Which of the following is an amorphous material?
A) Quartz
B) Glass
C) Iron
D) Copper
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Answer: B) Glass
Explanation: Glass lacks long-range atomic order, making it amorphous.
Q5. The maximum carbon content in steel is approximately:
A) 0.2%
B) 0.8%
C) 2%
D) 6%
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Answer: B) 0.8%
Explanation: Beyond 0.8% carbon, steel becomes cast iron (brittle).
Q6. Nitriding introduces which element into the surface of steel?
A) Carbon
B) Nitrogen
C) Oxygen
D) Chromium
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Answer: B) Nitrogen
Explanation: Nitriding hardens steel surfaces by forming nitrides without quenching.
Q7. The primary alloying element in stainless steel for corrosion resistance is:
A) Nickel
B) Chromium
C) Manganese
D) Copper
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Answer: B) Chromium
Explanation: Chromium forms a passive oxide layer protecting steel from corrosion.
Q8. Which of the following is used for gears due to high wear resistance?
A) Mild steel
B) Hardened steel
C) Aluminum alloy
D) Lead
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Answer: B) Hardened steel
Explanation: Hardened steel has high surface hardness, reducing wear in gear teeth.
Q9. Which heat treatment is used to relieve internal stresses?
A) Quenching
B) Annealing
C) Normalizing
D) Hardening
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Answer: B) Annealing
Explanation: Slow heating and cooling reduce residual stresses in metals.
Q10. The primary strengthening mechanism in aluminum alloys is:
A) Work hardening
B) Precipitation hardening
C) Grain refinement
D) Cold working
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Answer: B) Precipitation hardening
Explanation: Precipitation of fine particles blocks dislocation motion, increasing strength.