The evolution of the nanoscale dissipative structures in a distribution of defects within the isothermally irradiated f.c.c. crystal

摘要

A kinetic model for the influence of external noises such as fluctuations of thevacancies’ generation rate and inhomogeneity of irradiated f.c.c. crystal on theformation of nanoscale modulated dissipative structure in a spatial distribution ofvacancies is considered. The generation rate of vacancies all over the sites and adensity of their dislocation-type sinks are modelled as independent random uniformstationary fields and with certain defined parameters of fluctuation correlations—spatial and temporal ones. Such stochastic fields can induce a spatial redistributionof vacancies that can lead to their density stationary uniform field orstochastic one. By the average value and correlation functions of these fluctuations,the conditions are determined for interacting fluctuations of the vacancies’density, under which this homogeneous random field becomes unstable in relationto the stochastic field with a spatially periodic mean distribution of vacancies’density. For instance, with f.c.c. nickel as a model of the irradiated functionalmaterial, the temperature dependence of spatial period d(T) of the modulateddissipative structure of vacancies’ subsystem in f.c.c. crystal is numericallyforecasted and analysed, taking into account the total (‘electrochemical’ + ‘straininduced’)interaction between vacancies. Such d(T)-dependence is also determinedby the kinetic characteristics of vacancies’ redistribution.