MECH 2190 Engineering Materials Fundamentals
Sample Midterm
University of Windsor
GENG-2190 Engineering Materials Fundamentals
Midterm Sample Questions
1. Which type of crystal structure has 4 atoms/unit cell?
a. Simple Cubic
b. Body-Centered Cubic (BCC)
c. Face-Centered Cubic (FCC)
d. Hexagonal Close-Packed (HCP)
2. What type of interatomic bond is characteristic of metals?
a. Ionic
b. Covalent
c. Metallic
d. Van der Waals
3. The ability of a material to resist indentation or scratching is known as:
a. Ductility
b. Toughness
c. Hardness
d. Elasticity
4. Which of the following properties represents a material's resistance to plastic
deformation under load?
a. Hardness
b. Elasticity
c. Plasticity
d. Brittleness
5. The point at which a material transitions from elastic to plastic deformation is known
as the:
a. Yield strength
b. Modulus of elasticity
c. Tensile strength
d. Ultimate Tensile strength
6. The property that measures a material's ability to resist fracture from high-velocity
impact is:
a. Brittleness
b. Toughness
c. Hardness
d. Ductility
7. The phenomenon of a material's increased hardness and strength due to plastic
deformation is known as:
a. Annealing
b. Cold working
c. Tempering
d. Quenching
MECH 2190 Engineering Materials Fundamentals
Sample Midterm
8. Which of the following is a line defect in a crystal structure?
a. Vacancy
b. Dislocation
c. Interstitial
d. Grain Boundary
9. The process of recrystallization is driven by the presence of:
a. Dislocations
b. Vacancies
c. Twin boundaries
d. Grain boundaries
10. What is diffusion?
a. The movement of atoms in a random pattern
b. The movement of atoms from areas of high concentration to low concentration
c. The transfer of heat within a material
d. The deformation of a material under stress
11. What is the primary driving force for diffusion in solids?
a. Concentration gradient
b. Temperature gradient
c. Electrical potential
d. Pressure difference
12. In which type of diffusion do atoms move through the spaces between atoms in the
crystal lattice? a. Interstitial diffusion
b. Surface diffusion
c. Grain boundary diffusion
d. Vacancy diffusion
13. Examine the plane outlined with a dotted line in the unit cell. Select the correct
response below.
a. For an FCC structure, slip occurs on this plane.
b. For an FCC structure, this plane has 2 close packed directions.
c. For a BCC structure, this plane is a slip plane.
d. For a BCC structure, this plane is a close packed.
MECH 2190 Engineering Materials Fundamentals
Sample Midterm
14. Which of the elements is likely to be the most soluble in a solid solution with Copper (FCC, 0.128
nm)? Crystal structure and atomic radius are given in parentheses.
a.Chromium ( BCC, 0.125 nm)
b.Beryllium (HCP, 0.113 nm)
c.Silver (FCC, 0.144 nm)
d.Aluminum (FCC, 0.175 nm)
15. Which hardness scales should be used in the indentation test of Cu?
a.Rockwell A
b.Rockwell B
c.Rockwell C
d.Rockwell D
MECH 2190 Engineering Materials Fundamentals
Sample Midterm
Question 1.
The atomic radius of a Chromium atom is 0.125 nm nanometers.
Atomic Weight 52 g/mole
Chromium is a body-centred cubic metal.
The energy to form a vacancy in Chromium is 0.75 eV/atom.
A) Calculate the theoretical density of Chromium in g/cm3
B) Calculate the number of atoms in 1 cubic meter (m3) of Chromium.
C) Calculate the Number of vacancies in 1 cubic meter (m3) of Chromium at 200C.
Question 2
Rhodium(Atomic Weight 102.9 g/mole) has an atomic radius of 0.1345 nm and a density of
12.41 g/ cm3. Determine whether it has an FCC or BCC crystal structure.
Question 3
The diffusion coefficient for nickel in iron are given at two temperatures
T (˚C)
D (m2/sec)
1000
9.4x10-16
1200
2.4x10-14
A) Determine the value of D0 and the activation energy
B) At approximately what temperature would a specimen of Fe have to be exposed to Cu for 3h
to produce the same diffusion result as at 300°C for 12h?
Question 4
If a cylindrical rod of Nickel 100mm long and 8mm in diameter is heated from 20C to 200C
while its ends are maintained rigid, determine the change in the diameter. The linear coefficient
of thermal expansion of Ni is 13.3x10-6(C)-1, the Poisson’s Ratio of Ni is 0.31.
Question 5.
A) The table below lists the compositions of 2 alloys of silver (Ag) and Copper (Cu). Compute
the composition of each alloy using the units provided.
Solution:
Alloy
1
2
Amounts of Ag and Cu
20 grams of copper
80 grams of silver
20 grams of silver
5 grams of copper
Composition (wt.% Cu)
MECH 2190 Engineering Materials Fundamentals
Sample Midterm
Question 6. Calculate the composition, in weight percent, of an alloy that contains 218.0 kg
titanium, 14.6 kg aluminum, and 9.7 kg vanadium.
Question 7. What are the indices for the direction 1 indicated by the vector in the following
sketch?
1
1
1
Question 8. Consider a cylindrical specimen of a steel alloy 10.0 mm in diameter and 75 mm
long that is pulled in tension. Determine its elongation when a load of 20,000 N is applied.