Structure of aluminum alloys irradiated with reactor neutrons

Samples of the CAB-1 alloy in the initial state and irradiated with fast neutrons at an fluence of 2 x 10(21) neutrons/cm(2) have been studied by small-angle neutron scattering. It has been demonstrated that the observed large scattering cross sections are associated with the presence of nanosized pores with radii R similar to 5-50 nm in the alloy, whereas for possible inclusions of the Mg(2)Si and Si phases, the contrast factors and limiting volume fractions lead to the estimated cross sections that are two orders of magnitude smaller than those observed in the experiment. As a result of the irradiation, the volume fraction of scattering objects (pores) 40-50 nm in radius decreases by a factor of more than two. This is compensated, to a large extent, by an increase in the total fraction of particles with radii of 5-8 and 20-25 nm as the total surface area of the scattering objects increases by 40%.