Determination of the Velocity and Local Density of Mobile Dislocations Within Slip Bands in Neutron-Irradiated Copper by High Speed Cinematography

Abstract

The relation between the growth rates of slip bands in depth (S) and in length (vL) as resolved by high speed cinematography on the front surface of n-irradiated Cu crystals is used to determine the mean distance d (or local mobile density) of dislocations within the moving dislocation groups. Typical values are vL = 3 mm/s, d = 0.35 μm. The observations suggest that vL approximates the velocity of screw dislocations emerging from source regions near the surface. The effective free activation enthalpy ΔG deduced directly from vL agrees closely with the value determined indirectly from measurements of the CRSS.