The effect of fast neutron bombardment (2MeV, 252Cf source), to fluences of 1.07 x 1010/cm2, upon the linear thermal expansion of Li beta-alumina ceramics was studied. Two ceramic groups were prepared, in which the contents of the oxides of Li, Na, K and B were increased at the expense of alumina. Thermal expansion data indicated that both groups of samples exhibited a reduction in the mean thermal expansion coefficient during irradiation. This parallelled a shift in the lattice planes of the group with the higher alumina content and of the amorphicity of the other group. Annealing of the neutron-induced defects at 1000C reflected a partial recovery in the group with higher alumina contents. An approximately complete recovery of the other group of materials revealed a higher state of metamictization.

W.G.Osiris, I.A.Wafa: Radiation Effects and Defects in Solids, 1994, 128[4], 307-14