Chapter 4 Problems

Question 1

Type of Point Defects

Answer 1

• Vacancy
• Interstitial
• self- Interstitial
• Substitutional

Question 2

Type of Dislocations

Answer 2

• Edge (perpendicular)
• Screw (parallel)

Question 3

Vacancy Forumla

Answer 3

Qv: Activation Energy
k: Boltzmann’s Constant
T: Temp (add 273 to Celsius to get Kelvin)
N: potential defect sites
Density
N = —————– x Na
Atomic Mass

Question 4

Solvent vs Solute

Answer 4

Solvent: major concentration
Solute: minor concentration

Question 5

Substitutional vs Interstitial

Answer 5

Substitutional: metal in metal
Interstitial: non-metal in metal

Question 6

Substitutional Conditions

Answer 6

1. Radius
2. electronegativities
3. crystal structure
4. Valency (wants to go with higher one)

Question 7

BCC Tetrahedral

Answer 7

of sites: 24

Coordination Number: 4
# of sites: 24
# of atoms in cell: 12
r/R: 0.291

Question 8

BCC Octahedral

Answer 8

of Sites: 18

Coordination number: 6
# of sites: 18
# of atoms in cell: 6
r/R: 0.154

Question 9

FCC Tetrahedral

Answer 9

of sites: 8

Coordination Number: 4
# of sites: 8
# of atoms in cell: 8
r/R: 0.225

Question 10

FCC Octahedral

Answer 10

of sites: 13

Coordination Number: 6
# of sites: 13
# of atoms in cell: 4
r/R: 0.414