Microstructures Flashcards
A regular arrangement of atoms
Crystalline
An irregular arrangement of atoms
Amorphous
A mixture of Crystalline and Amorphous.
Semi crystalline
Atoms form repetitive patterns.
Unit cells
The application of shear stress along the length of an object causes crystal lattices to glide along each other
Slip systems
When atoms are in continuous contact.
Closely packed planes
Direction in unit cells along which atoms are in continuous contact.
Closely packed direction.
48 Slip systems, Good strength and moderate ductility.
BCC
12 Slip systems - Moderate strength and good ductility.
FCC
3 Slip systems
HCP
The surface that separates individual grains.
Grain boundaries
Initial process that occurs in the formation of a crystal from a liquid, solid, gas.
Rate of nucleation
Increase in size of grains in a material at a high temperature.
Growth rate.
Elongation under stress over a period of time, usually at elevated temps
Boundary sliding
A crystal where an atom is missing from one of the lattice sites
Vacancy
When an atom is replaced with a different type of atom.
Substitution
When an atom is replaced with a different type of atom (impurity).
Self-Interstitial
Where an atom of a different type occupies an interstitial site.
Interstitial
Defects in the orderly arrangement of a metals atomic structure.
Dislocation
The atomic plane starts to move which forms an extra portion.
Edge dislocation
Typical effect that occurs by screwing out the crystal, atomic plane forms a spiral staircase.
Screw dislocation.
Movement of edge dislocation across the crystal lattice under a shear stress.
Dislocation motion
A point below the melting point of metals where size and shape can change as well as properties.
Recrystallization temperature
Particle with no charge in an atom
Neutron
A subatomic particle with a negative charge that orbits the nucleus of an atom.
Electron
A subatomic particle with a positive electric charge.
Proton
Smallest constituent of a material
Atom
Smallest constituent that can be derived from a material whilst still maintaining its identity.
Molecule
When a pair of electrons are shared by an atom form the valence shell. Atoms will bond with other atoms to gain stability.
Covalent bonding
Unequal sharing of electrons
Polar covalent bonding
Equal sharing of electrons
Non-polar covalent bonding
Type of chemical bond that generates two oppositely charged ions.
Ionic Bonding
Dependency of valence electrons which are freely drifting in the lattice. Sea of electrons
Metallic Bonding
No regular ordering of atoms
Inert gas
Short ordered arrangement
Steam or Glass
Long range order
Metals or Solids
Sub energy levels
s (2),p (6),d (10),f (14),g(18),h(22),i(26)
Columns
Groups
Rows are known as?
Groups
