Study of material radiation porosity depending on technique and intensity of gas implantation

The gas effect on porosity development of an irradiated material depending on conditions of gas implantation is studied on the basis of the theory of binary clusters origination and gaseous porosity development in irradiated crystals taking into account gas mobility and finite solubility in the crystal, availability of heterogeneous sources of voids. It is established that the observed ambiguity of porosity parameters at equal gas concentrations and different character of its implantation can be explained by the difference in the conditions of void origination and growth governed by the technique of gas implantation. It is shown that the radiation induced porosity level at the given amount of implanted gas mostly depends on the way it has been implanted: before irradiation, in cold state and at the irradiation temperature; or along with irradiation, with different implantation intensities. In the case of preliminary implantation the void density will be less than in the case of coimplantation. In the second case the void density and swelling are highly sensitive to the implantation intensity, and depending on microstructural state of the material and irradiation conditions the intensity increase of gas implantation can result in the porosity level growth or its decrease. 13 refs.; 3 figs