Other point defects: self-interstitials, impurities

Schematic representationof different point defects:

• vacancy(1);
• self-interstitial(2);
• interstitial impurity(3);
• substitutional impurities(4,5)

The arrows show the local stresses introduced by the point defects.

Self-interstitials:

Self-interstitials in metals introduce large distortions in the surrounding lattice ⇒ the energy of self-interstitial

formation is ~ 3 times larger as compared to vacancies (Qi ~ 3×Qv) ⇒ equilibrium concentration of self-interstitials is very low (less than one self-interstitial per cm3 at room T).