Single Crystal and Poly-Crystalline Material

Single Crystal:

A single crystal is a solid which has a regular geometric structure in which the complete solid is a crystal. and in this type of crystal atoms extend over the entire volume of solid with regular periodic arrangements.

Single Crystal

Poly-crystalline:

poly crystalline solid has made by a large number of single grains crystals and this is presented in various directions and separated by boundaries and these boundaries are called grain boundaries.

Eg: The metals like copper, steel. etc.. are mostly used in simple engineering applications. and some of the powders are sugar, salt which are organic and inorganic materials which normally exist as Poly-Crystalline solids.
In a perfect single crystal, the atoms have a regular arrangement of atoms, this arrangement of atoms is done from one end of crystal to another end and in a compact mass.
In polycrystalline materials which are individual and randomly composed and these materials are oriented with other mechanisms.