Lattice distortion around vacancies

It was predicted that lattice distortions have little influence on the results of the calculations in the cluster calculations, and the present results also support this idea because no direct correlation of the variation of with the variations of flo and static displacements was observed in the course of the irradiation (11). The agreement between the recovery stages of Oo and E around 250°C (Fig. 5) indicates, however, that a small amount of depression still depends on the lattice distortion, because it is thought that Nb interstitial clustering has occurred at this temperature and the strain field is released by this effect and not by vacancy annihilation. As one can see from Fig. 5, the recovery of E at this temperature is much smaller than the recovery in the temperature range from 650 to 850°C, where vacancy annihilation is thought to be predominant. 

Point Defects. The simplest defect is a vacancy, where an atom is missing from its site in the lattice (Fig. 3.1). Another point defect is an interstitial, where an extra atom (e.g., impurity), without a proper lattice site, is forced into the lattice (Fig. 3.2). The insertion of an extra atom results in a distortion of the lattice around the interstitial... 

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