Grain boundary

A grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are 2D defects in the crystal structure, and tend to decrease the electrical and thermal conductivity of the material. Most grain boundaries are preferred sites for the onset of corrosion[1] and for the precipitation of new phases from the solid. They are also important to many of the mechanisms of creep.[2] On the other hand, grain boundaries disrupt the motion of dislocations through a material, so reducing crystallite size is a common way to improve mechanical strength, as described by the Hall–Petch relationship. The study of grain boundaries and their effects on the mechanical, electrical and other properties of materials forms an important topic in materials science.

Micrograph of a polycrystalline metal; grain boundaries evidenced by acid etching.
Differently oriented crystallites in a polycrystalline material

Share this article:

This article uses material from the Wikipedia article Grain boundary, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.