Crystallography Flashcards
Name the 4 types of crystal structure
- Simple Cubic Structure (cP)
- Body Centred Cubic Structure (BCC)
- Face Centred Cubic Structure (FCC)
- Hexagonal Close Packed Crystal Structure (HCP)
Symmetry in a cP structure
- ax = ay = az
- alpha = beta = gamma = 90deg
Percent Packing Efficiency in cP structure
52%
Coordination number of cP structure
6
Symmetry in a BCC structure
- ax = ay = az
- aplha = beta = gamma = 90deg
Coordination Number in a BCC structure
8
Percent Packing Efficiency in a BCC structure?
68%
Examples of cP structure
NaCl - Table Salt
Examples of metals with BCC structure
Iron, Chromium, Tungsten, Vanadium
What can FCC also be known as?
Cubic Closest Packed (CCP)
Symmetry in an FCC structure
- ax = ay = az
- alpha = beta = gamma = 90deg
Coordination number in an FCC structure
12
Percent Packing Efficiency in an FCC structure
74%
Examples of metals with FCC structure
Aluminium, Copper, Nickel, Cobalt
Order in Z direction for cP
AAAAAA
Order in Z direction for BCC
ABABAB
Order in Z direction for FCC
ABCABC
Symmetry in an HCP structure
- alpha = 120deg
- beta = gamma = 90deg
- ax = ay
Defects in Crystals
- Vacancies
- Dislocations
What kind of defect is a Vacancy?
Point Defect
What kind of defect is a Vacancy?
Point Defect
What kind of defect is a dislocation?
Linear Defect
What increases with quantity of dislocations?
Strength
5 types of imperfections in metal crystal structures
- Vacancy
- Self Interstitial Atom
- Interstitial Atom
- Substitutional atom (rsubrmatrix)
Describe self interstitial atom
Same type of atom, wrong place in lattice
Describe Substitutional Atom (rsub
Not same type of atom, right place in lattice, smaller than other atoms
Describe Substitutional Atom (rsub>rmatrix)
Not same type of atom, right place in lattice, bigger than other atoms
What is what?
A. Substitutional Solution (rsub>rmatrix)
B. Perfect Crystal
C. Interstitial Solution
D. Substitutional Solution (rsub
