Real Materials

Surfaces, Grain Boundaries, and Interfaces

· These are two-dimensional defects that separate regions of ordered single-crystal structure, crystalline and amorphous regions, or different phases.
· A bubble raft model of grain boundaries is shown below.

· The bubbles mimic atoms in a polycrystalline solid and their arrangement near the grain boundaries indicates the variable interatomic spacing in these regions.
· The lower the angle between equivalent planes in adjacent crystallites the less disorder occurs in the boundary.