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ESL
Defects in solids
Scope: know the different types of defect, and how these defects can affect on the materials properties
“Defect” can be either desirable or undesirable.
In general, a defect simply refers to a disruption in the crystalline order of an otherwise periodic material
Types of defects in crystal structure
1.Point defect
Vacancy atoms Interstitial atoms Substitutional atoms
Scope: know the different types of defect, and how these defects can affect on the materials properties
“Defect” can be either desirable or undesirable.
In general, a defect simply refers to a disruption in the crystalline order of an otherwise periodic material
Types of defects in crystal structure
1.Point defect
Vacancy atoms Interstitial atoms Substitutional atoms
2.Line defect
Dislocation
Dislocation
3.Area defect
Grain boundaries
Grain boundaries
Solid solution
Solid solution is a particular type of alloy
Two types: substitutional and interstitial
“solvent” – the host material, usually the element or compound
present in the greatest amount.
“solute” – the minor phase, added to the solvent. Usually the
element or compound present in minor concentrations.
“phase” is a region of uniform composition or crystal structure
What would a solid solution look like?
Solid solution is a particular type of alloy
Two types: substitutional and interstitial
“solvent” – the host material, usually the element or compound
present in the greatest amount.
“solute” – the minor phase, added to the solvent. Usually the
element or compound present in minor concentrations.
“phase” is a region of uniform composition or crystal structure
What would a solid solution look like?
LINE Defect- dislocation
Dislocation is a linear or one-dimensional defect.
Dislocations result from solidification from the melt, from mechanical work (e.g., rolling, drawing, compressive impact, tensile or shear stress), or from thermal stresses
It is very difficult to prepare a dislocation-free crystal!!!
Type of dislocation :
1. edge dislocation : a missing half plane of atoms
2. Screw dislocation: layers twisted with respect to each other
3. A combination of the two: Mixed
Dislocation is a linear or one-dimensional defect.
Dislocations result from solidification from the melt, from mechanical work (e.g., rolling, drawing, compressive impact, tensile or shear stress), or from thermal stresses
It is very difficult to prepare a dislocation-free crystal!!!
Type of dislocation :
1. edge dislocation : a missing half plane of atoms
2. Screw dislocation: layers twisted with respect to each other
3. A combination of the two: Mixed
Point defect