CH 5 Flashcards
(22 cards)
Define Vacansies
Produced when an atom is missing from its normal position in the crystal lattice.
Schottky Defect definition
Produced when an anion and a cation are missing from their normal positions in an ionic crystal.
Interstitial defects
Produced when an atom is lodged in the interstitial sites of a crystal lattice.
Frenkel defects
Produced when the smaller ion in an ionic crystal occupies an interstitial site.
Substitution also defects
Produced when an atom replaces an atom from its normal lattice position.
Edge dislocations
Produced when a number of atoms are missing from the lattice, or when there is an extra plane of atoms in the lattice.
Screw Dislocations
Produced by spiral stacking of crystal planes around the dislocation line.
Slip / glide
Slip is the movement of a dislocation along the slip plane.
Climb
Climb is the movement of dislocation out of the slip plane.
Cross slip
Is the movement of a dislocation from one slip plane into an intersecting plane.
Sessile dislocations
Stationary dislocations.
Grain boundaries
Are the area between adjacent grains.
Stacking faults
Refers to the improper stacking sequence of close packed planes.
Twins
Twins are planes across which there is a mirror image of orientation in the crystal structure.
Cold working / work hardening
Cold working is the plastic deformation of a metal at room temperature.
Alloying
Involves adding metallic or non-metallic elements to a metal to increase its strength.
Doping
Elements are added to semiconductors for the purpose of increasing electrical conductivity.
Grain refinement
This is the process of reducing the grain size of a material.
Strain hardening
Is the increase in strength of a metal due to previous plastic deformation.
Frank read source
During cold working, new dislocations are generated from existing dislocations.
Quenching
Involves the rapid cooling of a hot material.
Quenching
Involves the rapid cooling of a hot material.
