Influence of neutron irradiation and self-irradiation on crystal structure of Pu-Al and Pu-Ga δ-phase alloys

The influence was studied effected by neutron irradiation (NI) to fluences of 1.5x1015-3x1017 thermal n/cm2 and prolonged self-irradiation (SI) at temperatures ∼ 700C on the crystal structure of Pu-Ga and Pu-Al δ-phase alloys. It is shown that the metastable δ-phase of all the alloys indicated is resistant to NI. It is established that the irradiation of the alloys increases the lattice parameters depending on the Ga, Al concentration in the lattice of the δ-phase and leads to the anisotropic broadening of X-ray lines. NI and SI effected changes of the fine X-ray structure are mainly related to the realization the covalent constituent of the interatomic bond of atoms in the δ-crystal lattice. This realization becomes feasible due to the accumulation and evolution of irradiation induced defects that provide for a partial relaxation of internal stresses. 5 refs.; 4 figs. (author)