Physical Metallurgy — Part 1 MCQs with Explanations

Large number of slip systems is the correct answer to “A plastically deformed metal crystal at low temperature exhibits wavy slip line pattern due to”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Widmanstatten is the correct answer to “Which of the following microstructures of the eutectic is not observed in binary alloys”. This question is standard in competitive examination syllabi for Physical Metallurgy.

decreases because the oxygen ions supplied by the sodium oxide break the chain structure of the silicate slag is the correct answer to “Upon addition of sodium oxide to molten silicate slag, the viscosity of the slag”. This question is standard in competitive examination syllabi for Physical Metallurgy.

P-2, Q-4, R-3, S-1 is the correct answer to “A 0.4 wt% C steel is austenitised at 900°C for 1 hour and heat treated to get different. inicrostructures. Match the following microstructures to the heat treatments. P. Martensite + Retained austenite 1. Annealing Q. Ferrite + fine pearlite 2. Quenching R. Ferrite + spheroidal cementite 3. Quenching + temperature at 600°C S. Ferrite + coarse pearlite 4. Normalising”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Martensite is the correct answer to “Which of the following has the highest hardness number”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Both 'a' and 'r' are false is the correct answer to “Assertion: a : During hardening of steel, the component to be heat treated is strongly agitated in the quenching medium. Reason : r : The agitation breaks down the vapour barrier allowing the quench to proceed at a more rapid rate.”. This question is standard in competitive examination syllabi for Physical Metallurgy.

yield point phenomenon is the correct answer to “Stretcher strains found in a low carbon sheet are associated with”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Peritectic is the correct answer to “Identify the type of the following invariant reaction: liquid 1 + solid 1 ⇋ solid 2”. This question is standard in competitive examination syllabi for Physical Metallurgy.

All of them is the correct answer to “With increase in annealing temperature, the following defect density decreases.”. This question is standard in competitive examination syllabi for Physical Metallurgy.

5 is the correct answer to “The number of Bravais space lattices with two lattice points are”. This question is standard in competitive examination syllabi for Physical Metallurgy.

white cast iron is the correct answer to “Malleabilisation heat treatment is performed on”. This question is standard in competitive examination syllabi for Physical Metallurgy.

FCC, FCC, DC, HCP, DC is the correct answer to “What are the crystal structure of Cu, AI, Si, Zn and Ge”. This question is standard in competitive examination syllabi for Physical Metallurgy.

P-4, Q-3, R-2, S-1 is the correct answer to “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”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Dc = DNI is the correct answer to “In a dilute solid solution of nickel and carbon in y-iron.”. This question is standard in competitive examination syllabi for Physical Metallurgy.

P-4, Q-1, R-3, S-2 is the correct answer to “Match the heat treatment for an eutectoid steel shown in the TTT diagram below (as P, Q, R and S) with the resulting microstructure listed below: 1. Fine pearlite 2. martensite 3. Bainite 4. Coarse pearlite”. This question is standard in competitive examination syllabi for Physical Metallurgy.

P-2, Q-1, R-4, S-3 is the correct answer to “Match the phenomena listed in Group I with the possible mechanisms in Group II . Group I Group II P. Fatigue 1. Grain boundary sliding Q. Creep 2. Slip band extrusion and intrusion R. Strain hardening 3. Cottrell atmosphere S. Yield point phenomenon 4. Dislocation interaction”. This question is standard in competitive examination syllabi for Physical Metallurgy.

precipitation hardening is the correct answer to “An Al 4.5 mass% Cu alloy solutionising at 500°C, quenched to room temperature and aged at 200°C for 2 hrs is found to exhibit an increase in hardness. Theprimary mechanism contributing to increased hardness is”. This question is standard in competitive examination syllabi for Physical Metallurgy.

1 is the correct answer to “The low angle grain boundary occurs when the orientation difference between the adjacent grains is of the order of”. This question is standard in competitive examination syllabi for Physical Metallurgy.

pearlite + graphite is the correct answer to “An Fe - 3 wt % C - 1 wt % Si alloy is cooled very slowly from the liquid state to a temperature of 1023 K. Thereafter, it is cooled in air. The microstructure at room temperature will consist of”. This question is standard in competitive examination syllabi for Physical Metallurgy.

0.77 is the correct answer to “An annealed plain carbon steel, showing fully pearlitic microstructure, has a carbon content of . . . . . . . . wt%.”. This question is standard in competitive examination syllabi for Physical Metallurgy.

1265 is the correct answer to “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.”. This question is standard in competitive examination syllabi for Physical Metallurgy.

coherency strain is the correct answer to “In precipitation hardenable alloy like duralumin, intermediate precipitates can form due to”. This question is standard in competitive examination syllabi for Physical Metallurgy.

As the average grain size increases, the grain boundary energy per unit area deceases is the correct answer to “Identify the incorrect statement with respect to grain growth.”. This question is standard in competitive examination syllabi for Physical Metallurgy.

All are correct is the correct answer to “Coring is often being removed by subsequent”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Decreases is the correct answer to “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”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Small grain size is the correct answer to “Creep resistance decreases due to”. This question is standard in competitive examination syllabi for Physical Metallurgy.

38.1% Pb and 61.9% Sn is the correct answer to “What is the eutectic composition in Pb-Sn diagram”. This question is standard in competitive examination syllabi for Physical Metallurgy.

right and raised is the correct answer to “The net effect of continuous cooling on the TTT curves is that the curves are shifted to the”. This question is standard in competitive examination syllabi for Physical Metallurgy.

alloy steel is the correct answer to “Substantial amount of bainite can form during continous cooling in”. This question is standard in competitive examination syllabi for Physical Metallurgy.

76% ferrite and 24% pearlite is the correct answer to “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”. This question is standard in competitive examination syllabi for Physical Metallurgy.

$$x = A{t^{ - \frac{1}{n}}}$$ is the correct answer to “The relation between dendrite arm spacing (x) and the solidification time (t) is given by (A and n are constants)”. This question is standard in competitive examination syllabi for Physical Metallurgy.

decrease in grain size is the correct answer to “The hardenability of steels decreases with”. This question is standard in competitive examination syllabi for Physical Metallurgy.

90 degrees is the correct answer to “The angle between the line vector and the burgers vector of an edge dislocation is”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Q is the correct answer to “Which of the following cooling curves (shown in schematic) in an eutectoid steel will produce 50% bainitic structure”. This question is standard in competitive examination syllabi for Physical Metallurgy.

8.8 is the correct answer to “At 910°C γ-Fe transforms to α - Fe resulting in a percentage volume expansion of”. This question is standard in competitive examination syllabi for Physical Metallurgy.

Liquidus is the correct answer to “The boundary line between (liquid) and (liquid+solid) regions is called”. This question is standard in competitive examination syllabi for Physical Metallurgy.

4 is the correct answer to “Metal A nucleates as a spheres in a melt. Assuming Y(liquid/solid surface energy) = 200mJ/m 2 and ΔGv (change in volume free energy) = -10 8 J/M 3 the critical radius (in nm) for stable nuclei is”. This question is standard in competitive examination syllabi for Physical Metallurgy.

the same composition of the liquid but the weight fractions of the liquid are different is the correct answer to “Two Cu-Ni alloys, one with 47 wt.% Ni and the other with 53 wt.% Ni, are kept in separate crucibles and are allowed to equilibrate at the same-temperature T 1 between the liquidus and the solidus. The two alloys have”. This question is standard in competitive examination syllabi for Physical Metallurgy.

P-4, Q-1, R-2, S-3 is the correct answer to “Match the following. Gruop-I Gruop-II P. Line defect 1. Vacancy Q. Point defect 2. Grain boundary R. Area defect 3. Voids S. Volume defect 4. Dislocations”. This question is standard in competitive examination syllabi for Physical Metallurgy.

solid solution strengthening is the correct answer to “The primary strengthening mechanism in 70 : 30 brass is”. This question is standard in competitive examination syllabi for Physical Metallurgy.