Chapters 3&4

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A three-dimensional array of points that coincide with the atom position:

Lattice
The repetitve pattern of small groups of atoms os an atomic order in crystalline solids is called?

Unit Cell
Face Centered Cube:
# of atoms on corners?
# of atoms on center of each face?
Total # of atoms?
- corners: 8
- Faces: 6
- Total: 14
Body Centered Cube:
# of atoms on corners?
# of atoms in center of body?
Total # of atoms?
- corners: 8
- body: 1
- Total: 9
Hexagonal Close Packed
# atoms on corners?
# atoms in body?
Total # of atoms?
- corners: 12
- body: 5
- Total: 17
A crystal grain that has a perfect repetative arrangement of atoms through the entire specimen is called?

Single crystal
A crystalline specimen that has a collection of many small crystals or grains is called?

Polycrystal
The crystallographic direction of the physical properties in single crystals is called?

Anistropy
What are the three types of Lattice defects in a crystalline structure?
- 1)Point
- 2)Line
- 3)Area
What are the two types of Point defects?
- a) vacancy
- b) interstitial
What are the two types of Interstitial Point defects? and describe them...
- 1) self interstitial: becomes occupied with a host atom
- 2) substitutional interstitial: the host atom (solvent atom) gets replace by a foreign atom.
What factors must be determined in order for self interstitial substitution to occur?
- 1) Atomic size factor (<15%)
- 2) Crystal Structure (same)
- 3) Electronegativity (should be similar)
- 4) Valences (more likely to dissolve into a higher valency)
The type of line defect where a half plane of atom is missing within the crystal? The magnitude and direction of this dislocation is know as what?

Edge dislocation; Burger's vector
The type of line defect caused by a shear stress resulting in a "stair case" structure:

Screw dislocation

Author

Dusyat

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Chapters 3&4

Description

Chapter 3&4 Notes

Updated

2011-10-05T20:52:10Z

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