LXVIII. Direct observations of the arrangement and motion of dislocations in aluminium

Abstract

Electron optical experiments on Al foils have revealed individual dislocations in the interior of the metal. The arrangement and movement of individual dislocations have been observed. Most of the dislocations occur in the boundaries of a substructure, the diameter of the subrains being of the order of 1 μ, or more. Tilt-boundaries, networks and dislocation nodes have been resolved. The results apply to aluminium recovered at 350°c after heavy deformation by beating; the dislocation density is 10¹⁰/cm². The dislocations can be seen to move along traces of (111) slip planes; the motion of the dislocations can be either rapid or slow and jerky. Cross-slip by the screw dislocation mechanism has been observed frequently.