Chapter 4 defects in solids Flashcards
why are defects important
defects have a huge impact on the various properties of materials
- defects are responsible for color and price of a diamond
- forging a metal tool introduces defects and increases the strength of the tool
defects can be introduced or removed during ________
Processing
point defects
are lattice defects of zero dimensionality, i.e., they do not possess lattice structure in any dimension. Typical point defects are impurity atoms in a pure metal, vacancies, and self-interstitials.
vacancies
is a type of point defect in a crystal where an atom is missing from one of the lattice sites.
interstitial defect
is a type of point crystallographic defect where an atom of the same or of a different type, occupies a normally unoccupied site in the crystal structure.
point defects in metals
equilibrium concentration
Equilibrium is when the rate of the forward reaction equals the rate of the reverse reaction. All reactant and product concentrations are constant at equilibrium.
Boltzmann’s constant
activation energy
the minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction.
measuring activation energy
estimating vacancy concentration
observing vacancy ( continued )
impurities
are foreign atoms that replace some of the atoms making up the solid or that squeeze into the interstices
atoms that are different from the host
a homogeneous material
or system has the same properties at every point
solids with impurities