The behaviour of dislocations in neutron-irradiated aluminum

Abstract

Observations were made on the difference in behavior of ermoving dislocations in lrradiated and unirradiated aluminum foils. Two types of specimens were irradiated: a thinned foil mounted in an aluminum specimen holder and a sheet 0.00l thick, which was thinned after irradiation. The observations showed that the movement of the dislocations in both types of the irradiated aluminum was slow and jerky. This was in marked contrast with the movement observed in unirradiated aluminum foils which was usually so fast that it could be observed only by the slip traces which remained. On annealing the irradiated foil, no change in behavior was observed until a temperature of at least 200 deg C was reached when some unimpeded movement of dislocations occurred. The traces left by the moving dislocations in the irradiated material persisted for a much longer time than those in the unirradiated material. Certain conclusions are drawn from the observations. (P.C.H.)