1985 Volume 26 Issue 4 Pages 225-229
Deformation induced substructures of aged Al–Li alloys containing coherent δ′–Ll2 ordered particles have been studied by dark field transmission electron microscopy. Dislocations move in pairs when a fine scale precipitation of δ′ occurs. The observed shape of dislocations and the separation distance between the dislocations in a pair strongly depend on the size and distribution of δ′. Particles with diameter less than 50 nm are sheared by moving dislocation pairs. Dislocations by-pass the larger particles leaving dislocation loops.
Planar arrangement of deformation induced dislocations, which is generally considered to be responsible for the poor ductility of the present alloys, has not been observed for any aging stage investigated in the alloy with a high Li content.
