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26 Cards in this Set
- Front
- Back
Imperfections |
An idealized solid does not exist; all containlarge numbers of various defects or imperfections. |
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Point Defect |
An imperfection associated with one or two atomic positions. |
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Vacancy |
A point defect in which an atom is missing from a normally occupied lattice site. |
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k Boltzmann's constant |
1.38 x 10^-23 J/atom.K or 8.62 x 10^-5 eV/atom.K |
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self interstitial |
An atom from the crystal that is crowded into an interstitial site a small void space that under ordinary circumstances is not occupied. |
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alloy |
A material in which impurity atoms have been intentionally added to impart specific characteristics to the material. |
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Solid Solution |
A solid solution forms when, as the solute atoms are added to the host material, thecrystal structure is maintained and no new structures are formed.A solid solution is also compositionally homogeneous; the impurity atoms are randomly and uniformly dispersedwithin the solid. |
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Solute/Solvent |
Solvent is theelement or compound that is present in the greatest amount; on occasion, solvent atomsare also called host atoms. Solute is used to denote an element or compound present ina minor concentration.
Solute to the Solvent. |
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Substitutional Solid Solution |
Solute or impurity atoms replace or substitute for the host atoms.Atomic size factor. Appreciable quantities of a solute may be accommodated inthis type of solid solution only when the difference in atomic radii between thetwo atom types is less than about 15%. Otherwise, the solute atoms create substantial lattice distortions and a new phase forms.2. Crystal structure. For appreciable solid solubility, the crystal structures for metalsof both atom types must be the same.3. Electronegativity factor. The more electropositive one element and the more electronegative the other, the greater the likelihood that they will form an intermetallic compound instead of a substitutional solid solution.4. Valences. Other factors being equal, a metal has more of a tendency to dissolveanother metal of higher valency than to dissolve one of a lower valency. |
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Interstitial Solid Solution |
Impurity atoms fill the void or interstices among teh two host atoms. Either tetrahedral or octahedral for FCC and BCC |
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Composition/Concentration |
Specified by either weight percent or atom percent |
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Weight Percent |
The weight of a particular element relative to the total alloy weight. C1 =m1/(m1 + m2)* 100 |
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Atom Percent |
The number of moles of an element in relation to the total moles of the elements in the alloy. Number of Moles = Mass (g) / Atomic Weight C 1' =(nm1) /(nm1 + nm2)* 100 |
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Edge Dislocation |
A dislocation in which an extra portion of a plane of atoms or half plane the edge of which terminates within the crystal.
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Dislocation Lineabout:newtab |
a linear defect that centers on the line that is defined along the end of the extra half plane of atoms |
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Screw dislocation |
the upper front region of the crystal is shifted one atomic distance to the right relative to thebottom portion. The atomic distortion associated with a screw dislocation is also linearand along a dislocation line
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Mixed Dislocation |
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Burgers Vector |
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Atomic Vibration |
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Microstructure |
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microscopy |
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photomicrograph |
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transmission electron microscope` |
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scanning electron microscope |
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scanning probe microscope
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grain size |
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