Term
| What are the three bonds and their characteristics? |
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Definition
Ionic -- very strong -- non-directional--hard and brittle
Covalent -- very strong -- directional--hard and brittle
Metallic--weaker bond--non-directional-- ductile and malleable
Van der Waals -- very weak -- Ductile |
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Term
| What causes deformation? What are the types of deformation? |
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Definition
Any force applied to an object (Newton's second law -- equal and opposite)
Elastic Deformation -- reversible
Plastic Deformation -- permanent |
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Term
| What causes deformation? What are the types of deformation? |
|
Definition
Any force applied to an object (Newton's second law -- equal and opposite)
Elastic Deformation -- reversible
Plastic Deformation -- permanent |
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Term
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Definition
| Below this point the material is in elastic deformation and this is reversible |
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Term
| In Hooke's Law what is proportional? |
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Definition
| elastic strain and stress are proportional |
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Term
| What do all the components of Bragg's law mean? |
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Definition
N = integer
λ = wavelength
d = spacing between planes
Theta = angle |
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Term
| A solid is crystalline when... |
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Definition
| ... it has long range periodicity |
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Term
| what is the approx diameter of an atom? |
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Definition
| 3x10 to the negative ten m. |
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Term
| The glide of dislocations can cause what? |
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Definition
| Plastic deformations -- these deformations are most often caused by the glide of dislocations |
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Term
| the equilibrium concentration of vacancies in a crystal increases with what? |
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Definition
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Term
| What do grain boundaries do? |
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Definition
| Increase strength of material by preventing the slip of dislocations |
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Term
| What do grain boundaries do? |
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Definition
| Increase strength of material by preventing the slip of dislocations |
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|
Term
| Definition of crystal dislocation? |
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Definition
| a line defect that by its motion causes glide by one atom spacing over the area over which it has moved |
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Term
|
Definition
|
|
Term
| Modulus is related to what? |
|
Definition
|
|
Term
| strain is proportional to what |
|
Definition
|
|
Term
| stress is proportional to what? |
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Definition
|
|
Term
| What are a crystal's properties determined by? |
|
Definition
Crystal structure
Defects
Bonding |
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Term
|
Definition
Atoms missing or in irregular places in the lattice
- vacancies
- impurities
- interstitials
- substitution impurity
-- 0 D |
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Term
|
Definition
Groups of atoms in irregular positions
- screw
- edge dislocation
-- 1D |
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Term
|
Definition
The interfaces between homogeneous regions of the material
- Grain Boundaries
- External Surfaces |
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Term
|
Definition
Extended Defects
- pores
- cracks
-- 3D |
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Term
|
Definition
Material transport through atomic motion. Those materials which are not homogeneous can be made homogeneous though diffusion
-- must have a high temperature to overcome atomic barriers |
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Term
|
Definition
| to jump from lattice site to lattice site atoms need activation energy (thermal energy from atomic vibrations) |
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Term
|
Definition
Absences of an atom from its normal location in a perfect crystal
the number of vacancies increases with the temperature |
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Term
| Point defects do what to the lattice |
|
Definition
| introduce distortions. These distortions can feel and interact with each other and external stresses |
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Term
|
Definition
| impede dislocations and strengthen a material |
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Term
|
Definition
- Work Hardening
- Alloy
- Smaller Grain Size
- Two Structures |
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|
Term
|
Definition
can not interrogate a material unless the light source is small enough. X-rays are best
your resolution is only limited by diffraction and the resolution is on the order of the wavelength |
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Term
| The lower the modulus or spring constant |
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Definition
| the more the object will streach |
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Term
|
Definition
Stress over strain
rise over run |
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Term
|
Definition
|
|
Term
|
Definition
| applied pulling force or strength |
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Term
| Where is the work hardening region on the stress strain curve |
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Definition
| after the yield strength point |
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Term
| When will a metal be brittle? how can this be fixed |
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Definition
| when there are too many dislocations in the lattice. It can be fixed by putting the metal into a furnace but NOT necessarily melting it. During this process the dislocations should destroy each other. This is explained by the second law of thermodynamics |
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Term
| What does a dislocation look like on his diagram thing |
|
Definition
| sort of like you would expect a couple of vacancies to look |
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|
Term
| What does a model of a dislocation look like |
|
Definition
| like a 3D representation of a block of atoms but in the center there is a group of (yellow) atoms which throw off the symmetry |
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Term
| dislocations are responsible for what kind of deformations |
|
Definition
| plastic deformations (irreversible) |
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Term
| What is behind bending a wire back and forth until it breaks? |
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Definition
| Dislocations are moving throughout the structure |
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Term
| What types of metals to dislocations have a difficult time moving through |
|
Definition
FCC Bronze
BCC Iron
Stone |
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Term
| When is Bragg's law satisfied? |
|
Definition
| When intensity spikes in a sharp peak (i.e. the wavelengths are in sync) |
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Term
| Dislocations allow a material to do what more easily than the theory would think? |
|
Definition
| Allows the material to plastically deform |
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|
Term
| Another def of Stress in case you weren't confused enough already! |
|
Definition
|
|
Term
|
Definition
| change in size divided by original size |
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Term
| According to Hooke's law what is proportional? |
|
Definition
Stress and elastic strain
omg you already have this card... play it again, Sam. Play it as time goes by
or play it, Sam, play it as time goes by... whichever floats your boat... need to study... concentration... 64...? NO! that's not what I want... I can haz veggie burger? |
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Term
| What is the constant in Hooke's law called? |
|
Definition
Young's modulus
symbol -- E |
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Term
| What strength reducing deformation increases with temperature in metals and can do a great deal of damage? |
|
Definition
Creep
The slow deformation of a material through stresses |
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