Oliinyk O. Physical Kinetics of Modulation of Distribution of Vacancies in Cubic Crystals under Irradiation

The numerical and analytical calculations of energy parameters for 'strain-induced' and 'electrochemical' interactions of vacancies within the f.c.c. crystal are carried out. Their behaviour near and far from the centre of the f.c.c.-lattice reciprocal-space Brillouin zone (particularly, on its surface) is studied. As shown, the period of the modulated structure in a spatial distribution of vacancies formed by means of the spinodal mechanism (in a closed system) increases with temperature and is determined by the entropy factor, 'electrochemical' interaction of vacancies, and elastic properties of f.c.c. crystal. As revealed, in the case of open system and completely lacking both external fluctuations of generation rate of radiation point defects (e.g., vacancies) and internal fluctuations of inhomogeneity in arrangement of their dislocation sinks, if density of dislocations is temperature independent, the period of the dissipative modulated structure in a spatial distribution of vacancies decreases slightly with temperature increasing and is conditioned by 'electrochemical' interaction of vacancies. Accounting (empirical) temperature dependence of density of dislocations leads to increasing the dissipative modulated structure period with temperature that is caused by the entropy factor and 'electrochemical' interaction of vacancies. The period of superlattice of nanovoids increases with temperature since it is determined only by their elastic interaction. As quantitatively illustrated, the temperature interval of stationary existence of the dissipative modulated structure in vacancies' subsystem density distribution in f.c.c. crystal is narrowed, if external fluctuations of nonzero rate of generation of point defects are activated.