Physical Metallurgy - Study Mode

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[#81] A defect that is bounded by two mirror planes is

(A) twin

(B) stacking fault

(C) grain boundary

(D) edge dislocation

Correct Answer

(A) twin

[#82] The growth rate of pearlite, v, and the interlamellar spacing S are given by the following relation, $$v = k.frac{1}{S}left( {frac{{1 - {S_c}}}{S}}
ight)$$ xa0 xa0where 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 c 2

Correct Answer

(A) S = S c

[#83] Malleabilisation heat treatment is performed on

(A) cast steel

(B) gray cast iron

(C) white cast iron

(D) spheroidal graphite cast iron

Correct Answer

(C) white cast iron

[#84] What are the crystal structure of Cu, AI, Si, Zn and Ge?

(A) FCC, FCC, DC, HCP, DC

(B) FCC, FCC, BCC, HCP, BCC

(C) FCC, FCC, DC, BCT, DC

(D) FCC, FCC, BCC, HCP, DC

Correct Answer

(A) FCC, FCC, DC, HCP, DC

[#85] Match the basic strengthening mechanisms in the following materials. Group-I Group-II P. 60 : 40 brass is stronger than 70 : 30 brass. 1. Case hardening Q. An automobile gear made from 0.6% C steel and quenched in water from a temperature of 850°C. 2. Strain hardening R. Tungsten filament drawn at a temperature of 400°C. 3. Martensitic strengthening S. A ball bearing heated in furnace in ammonia atmosphere. 4. Second phase strengthening

(A) P-4, Q-3, R-2, S-1

(B) P-1, Q-2, R-3, S-4

(C) P-4, Q-3, R-1, S-2

(D) P-3, Q-4, R-2, S-1

Correct Answer

(A) P-4, Q-3, R-2, S-1