A grain is a a portion of a solid metal (usually a fraction of an inch in size), in which the atoms are arranged in an orderly pattern. The irregular junction of two adjacent grains is known as a grain boundary. This narrow zone corresponds to the transition from one crystallographic orientation to another, thus separating one grain from another.
A surface defect representing the boundary between two grains. The lattice has a different orientation on either side of the grain boundary. Interstitialcy. Atom occupying an interstitial site not normally occupied by an atom in the perfect crystal structure or an extra atom inserted into the perfect crystal such that two atoms occupy positions close to a singly occupied atomic site in the perfect structure.
a thin layer of atoms located in between two separate crystals or grains of a polycrystalline material.
a sink for vacancies so that regions adjacent to the boundary are unable to nucleate the precipitates, even though the matrix may be supersaturated with solute
The boundary between grains (or crystals) that are misoriented with respect to one another.
A narrow zone in a metal corresponding to the transition from one crystallographic orientation to another, thus separating one grain from another; the atoms in each grain are arranged in an orderly pattern; the irregular junction of two adjacent grains is known as a grain boundary.
the interface between the grains or crystals.
A planar feature separating two grains, defined by a large change in crystallographic orientation, or change in mineralogy across the plane. There is a somewhat arbitrary definition of what angle constitutes a grain boundary vs a sub-grain boundary, but in minerals we usually use an angle between 10 and 15 degrees.
A grain boundary is the interface between two grains in a polycrystalline material. Grain boundaries disrupt the motion of dislocations through a material so reducing crystallite size is a common way to improve strength, as described by the Hall-Petch relationship. Since grain boundaries are defects in the crystal structure they tend to decrease the electrical and thermal conductivity of the material.