PE Metallurgical and Materials Engineering Practice Exam
Verified Questions, Correct Answers, and Detailed
Explanations for Science Students||Already Graded A+
1. Which crystal structure has the highest atomic packing factor (APF)?
A. Face-centered cubic (FCC)
FCC has an APF of 0.74, the highest among common crystal structures.
2. The number of atoms per unit cell in a body-centered cubic (BCC) structure
is:
B. 2
BCC has 1 atom at the center and 8 corner atoms each contributing 1/8.
3. Which defect involves an extra half-plane of atoms?
C. Edge dislocation
Edge dislocations are characterized by an inserted half-plane of atoms.
4. Grain boundaries generally increase which property?
A. Strength
Grain boundaries impede dislocation motion, increasing strength.
5. Which mechanism primarily controls diffusion in substitutional alloys?
D. Vacancy diffusion
Substitutional atoms require vacancies to move through the lattice.
6. Fick’s First Law applies to which condition?
B. Steady-state diffusion
It assumes a constant concentration gradient over time.
, 7. The driving force for diffusion is:
C. Concentration gradient
Atoms diffuse from regions of high to low chemical potential.
8. Which phase diagram feature indicates equilibrium between three phases?
A. Eutectic point
At the eutectic point, liquid transforms into two solid phases.
9. In the Fe–Fe₃C diagram, pearlite consists of:
B. Ferrite and cementite
Pearlite is a lamellar mixture of ferrite (α) and cementite (Fe₃C).
10. Which heat treatment increases ductility while reducing strength?
D. Annealing
Annealing promotes recrystallization and grain growth.
11. Quenching steel primarily increases:
A. Hardness
Rapid cooling forms martensite, a very hard phase.
12. Tempering martensite results in:
C. Reduced brittleness
Tempering allows controlled decomposition of martensite.
13. Which strengthening mechanism relies on solute atoms?
B. Solid solution strengthening
Solute atoms distort the lattice and hinder dislocation motion.
Verified Questions, Correct Answers, and Detailed
Explanations for Science Students||Already Graded A+
1. Which crystal structure has the highest atomic packing factor (APF)?
A. Face-centered cubic (FCC)
FCC has an APF of 0.74, the highest among common crystal structures.
2. The number of atoms per unit cell in a body-centered cubic (BCC) structure
is:
B. 2
BCC has 1 atom at the center and 8 corner atoms each contributing 1/8.
3. Which defect involves an extra half-plane of atoms?
C. Edge dislocation
Edge dislocations are characterized by an inserted half-plane of atoms.
4. Grain boundaries generally increase which property?
A. Strength
Grain boundaries impede dislocation motion, increasing strength.
5. Which mechanism primarily controls diffusion in substitutional alloys?
D. Vacancy diffusion
Substitutional atoms require vacancies to move through the lattice.
6. Fick’s First Law applies to which condition?
B. Steady-state diffusion
It assumes a constant concentration gradient over time.
, 7. The driving force for diffusion is:
C. Concentration gradient
Atoms diffuse from regions of high to low chemical potential.
8. Which phase diagram feature indicates equilibrium between three phases?
A. Eutectic point
At the eutectic point, liquid transforms into two solid phases.
9. In the Fe–Fe₃C diagram, pearlite consists of:
B. Ferrite and cementite
Pearlite is a lamellar mixture of ferrite (α) and cementite (Fe₃C).
10. Which heat treatment increases ductility while reducing strength?
D. Annealing
Annealing promotes recrystallization and grain growth.
11. Quenching steel primarily increases:
A. Hardness
Rapid cooling forms martensite, a very hard phase.
12. Tempering martensite results in:
C. Reduced brittleness
Tempering allows controlled decomposition of martensite.
13. Which strengthening mechanism relies on solute atoms?
B. Solid solution strengthening
Solute atoms distort the lattice and hinder dislocation motion.
