Crystallite
Crystallites are crystals that do not or only partially show the actual crystal form. In metallurgy and petrography , crystallites are also referred to as grain .
Crystallites arise when crystals solidify in a melt in which they are prevented from growing freely by surrounding crystals. They solidify to a polycrystalline structure with a mostly microscopic grain size . The neighboring crystallites of a polycrystal differ in the orientation of their crystal structure .
On micrographs of polished and acid- treated metal or rock specimens, the transitions from one crystallite to the next, known as grain boundaries , can be seen as dark lines or color changes.
The technical importance of crystallites is high, so they have a decisive influence on the creep of materials, especially in high-temperature applications , and hinder the spread of dislocations , which is exploited in fine-grain hardening .
See also
Individual evidence
- ↑ Christoph Broeckmann, Paul Bite: Materials Science I . Institute for Material Applications in Mechanical Engineering at RWTH Aachen University , Aachen 2014.