Elongated dislocation loops and the stress-strain properties of copper single crystals

Abstract

Abstract The formation of elongated dislocation loops in deformed copper single crystals has been studied by transmission electron microscopy. A mechanism by which elongated loops could be formed is considered in detail. The density of these loops was found to increase only slightly during stage I of the stress-strain curve, but during the transition from stage I to stage II the density increased from about 5 × 1011 loops/cm3 to about 1013 loops/cm3. A model is proposed for work-hardening in the easy glide and transition regions, in which the dislocation loops indirectly act as obstacles to moving screw dislocations.