The velocity of edge and screw dislocations in primary slip bands, and the formation rate of primary slip bands, were measured during the stage-I deformation of neutron-irradiated monocrystals by using various strain rates at room temperature. It was found that the average velocity of edge dislocations was greater, by at least an order of magnitude, than that of the screw dislocations. The velocity of screw dislocations did not depend so strongly upon the strain rate. The formation rate of primary slip bands was proportional to the strain rate. On the basis of these results, it was concluded that jogs which were produced on moving dislocations, by cutting dislocation loops, led to the difference in velocity of the edge and screw dislocations. Also, the change in the density of mobile dislocations, as well as the velocity of the dislocations, was responsible for the change in the plastic strain rate.

S.Kitajima, K.Shinohara, M.Kutsuwada: Materials Transactions, 1995, 36[5], 626-31