IMPERFECTIONS IN SOLIDS

Cards (108)

  • Site from which an atom is missing.
    Surface analogue of a vacancy defect.
  • Crystalline defect
    A lattice irregularity having one or more of its dimensions on the order of an atomic diameter.
  • Point defects
    Atoms are missing or in irregular places in a crystal lattice.
  • Vacancy
    Simplest type of a point defect.
  • Another name of vacancy.
    Vacancy lattice site
  • An absence of an atom from its normal location in a perfect crystal structure.
    Vacancy
  • Bonding + Crystal structure + Defects = Properties
  • All crystalline solids contain vacancies and it's impossible to create materials without vacancies.
  • Temperature
    Dependence of the equilibrium number of vacancies.
  • Self-interstitial
    An atom from the crystal that is crowded into an interstitial site.
  • Interstitial site
    Small void space that under ordinary circumstance is not occupied.
  • Interstitial site
    Exists in very small concentrations, lower than vacancies.
  • Interstitial site

    In metals it introduces relatively large distortions in the surrounding lattice because the atom is substantially larger than the interstitial position in which it is situated.
  • Impurities
    Another name of a foreign atom.
  • Impurities.
    Atoms which are different from the host atoms.
  • In pure metals, impurity or foreign atoms will always be present, some will exist as crystalline point defects; no only one type of atom.
  • Alloy
    Deliberate mixture of atoms.
  • Alloy
    Impurity atoms have been intentionally added to impart specific characteristics to the material.
  • Another term for solid solution.
    Second phase
  • Solid solution
    Result of addition of an impurity atom into a metal, depending on the kinds, concentration, and temperature of an alloy.\
  • Solute
    Elements/compound in a minor concentration.
  • Solvent
    Element/compound in the greatest amount.
  • Another term for solvent.
    Host atom
  • Solid solution
    Crystal structure must be maintained and no new structure is made. thus making it homogeneous after the mixing of a solute to a host material.
  • Solid solution
    Contains dispersed impurities.
  • Solubility
    Ability to dissolve.
  • Liquid solution
    Formed when two liquids which are soluble with each other are combined and its composition is homogeneous throughout.
  • Impurity point defects are found in solid solutions.
  • Two types of solid solutions
    Substitutional and Interstitial
  • Substitutional solid solution

    A solute or impurity atom will replace the host atoms.
  • Interstitial solid solution
    An impurity atom will fill the voids or interstices among the host atoms.
  • In atomic size factor, appreciable quantities of a solute may be accommodated in this type only when the difference in atomic radii between the two atom type is less than about +_15%. Otherwise the solute atoms will create substantial lattice distortions and a new phase will form.
  • Crystal structure for metals of both atom types must be the same.
  • The more electropositive one elements and the more electronegative the other, the greater is the likelihood that they will form an intermetallic compound rather than a substitutional solid solution.
  • Electronegativities must be compatible.
  • A metal will have more of a tendency to dissolve another metal with high valency than that of a lower valency.
  • Metals with high APF will have interstitial position that is small.
  • Atomic diameter of an interstitial impurity atom must be substantially smaller than that of the host atoms.
  • Normally, the maximum concentration of interstitial impurity atom is less than 10%.
  • Dislocations
    Linear/one dimensional defect around which some of the atoms are misaligned.