DISLOCATION DISTRIBUTION IN DEFORMED SILVER SINGLE CRYSTALS

Abstract

The results of an electron transmission microscopy investigation of silver single crystals deformed in the three stages of the work-hardening curve are described. In stage I edge-dislocation bundles of the primary system form. With continued deformation in stage I more bundles form and the number of dislocations in each bundle increases. The end of stage I is associated with activity on secondary glide systems adjacent to the bundles. During stage II deformation, a cell structure forms and continually decreases in size by the cooperative activity of the primary and secondary systems. This cooperative activity occasionally results in the formation of dense networks of Lomer–Cottrell dislocations in local areas. Often associated with these networks are small stacking-fault tetrahedra believed to result from the stress-induced cross slip of extended dislocations at jogs. The importance of the stacking-fault energy in the deformation of f.c.c. crystals is discussed.