Evolution of dislocation structure during deformation of gamma-irradiated LiF crystals

The effect of gamma irradiation on the mechanical characteristics and dislocation structure of slip bands in LiF crystals is studied at doses D less than or equal to 7.3 x 10(8) R. Irradiation causes a substantial increase (up to a factor of 30) in the yield stress tau(y) of the crystals, with tau(y) proportional to D-0.4 in the first approximation. The deformation shear increases in the slip bands of irradiated crystals, as do the densities of the screw and edge dislocation components, while the dislocation mean free paths decrease. Irradiation also raises the probability of twinning cross slip for screw dislocations, The observed effects are assumed to be related to the formation of a different kind of defects in the irradiated crystals, primarily clusters of implanted atoms. (C) 1997 American Institute of Physics.