Chapter 4 Flashcards
What are the types of imperfections?
- 0 Dimensional (point)
- 1 Dimensional (linear)
- 2 Dimensional (Planar/interfacial)
- 3 Dimensional (volume)
Give 3 examples of point defects
- Vacancy Atoms
- Interstitial atoms
- Substitutional atoms
Give an example of a linear defect
Dislocations
Give 3 examples of planar/interfacial Defects
- Grain Boundaries
- Twin Boundaries
- Stacking Faults
Give 3 examples of volume defects
- Impurity inclusions
- Pores
- Cracks
What is a vacancy?
- A point defect where there are vacant atomic sites in the structure
What is an interstitual atom?
A point defect where an atom is added into the structure
Extra atoms are added between atomic sites.
What is a substitutional atom?
A point defect where one atom is replaced with another different atom not orignally in the structure
What is the equilibrium concentration for point defects formula?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/155/936/106/a_image_thumb.png?1659473116)
For Point Defects in Alloys, what are two outcomes if an impurity (B) is added to a host (A)
- Solid solution of B in A (i.e. random dist. of point defects)
- Solid solution of B in A plus particles of a new phase (usually for a larger amount of B)
What are the weight percent and atom percent formulas?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/155/936/557/a_image_thumb.png?1659473118)
What are dislocations?
- They are line defects that produce permanent plastic deformation
- Are 1D defects around which atoms are misaligned
- Slip between crystal planes result when dislocations move
![](https://s3.amazonaws.com/brainscape-prod/system/cm/155/936/588/a_image_thumb.png?1659473118)
What are the 2 Types of Linear dislocations?
- Edge dislocation
- Screw Dislocation
What is an edge dislocation?
- Dislocation where an extra portion of a plane of atoms, or half-plane has been inserted into the structure.
- The edge terminates within the crystal
- The burgers vector is perpendicular to the dislocation line
What is an screw dislocation?
- Spiral planar ramp resulting from shear deformation
- Burgers Vector is parallel to dislocation line