Explanation

The lattice of normal atoms in crystal after being removed is a form of point defect. There are two types of vacancy formation: one is that displaced atoms migrate continuously and finally locate on the surface, which is called Schottky defect; the second is called Frenkel defect, which includes both interstitial atoms and vacancy, so it requires large energy to form. This type of defect usually does not exist in metals. In an incomplete crystal, the intergranular boundary, phase interface and dislocation pair vacancy, which is conducive to the formation and disappearance of vacancy. Generally, supersaturated vacancy can be generated in crystal by high temperature quenching or high-energy particle radiation.

Classification