The dissipative modulated structures in a distribution of interacting vacancies in the elastically anisotropic body-centred cubic crystals under an isothermal irradiation

ABSTRACT

Dissipative mechanism of formation of a modulated structure of vacancies in a body-centred cubic (b.c.c.) crystal is considered as its intrinsic property under an isothermal irradiation irrespectively of elastic-anisotropy factor sign. Conditions of self-organisation of a precursor of formation of a ‘superlattice’ of nanovoids, namely, the modulated structure in a spatial distribution of the diffusing vacancies generated by irradiation, because of the instability of their homogeneous distribution as a result of interaction between them in a b.c.c. host crystal under irradiation, are analysed. As shown for the first time, the ‘cohesive’ and ‘elastic’ couplings between interacting (and diffusing) vacancies have a crucial role in a pattern-selection process accordingly with different (positive or negative) elastic-anisotropy factors.