An investigation is made of the dislocation structure forming upon straining high‐purity single crystals within the range from 77 to 573 °K. The single crystals were extended along the 〈100〉 and 〈110〉 axes. The dislocation structure observation was made in an electron microscope using thin foils cut from deformed specimens. It was established that screw dislocations uniformly distributed in size are predominant in the dislocation structure of deformed crystals at temperatures below room temperature irrespective of the axis orientation of extension. Increasing of the deformation temperature leads to the disappearance of the screw dislocations in the dislocation structure and to formation of a cellular structure. It is shown that at and below room temperature considerably higher growth rate of dislocation density with deformation is observed in crystals extended along the 〈100〉 axis. The dislocation density dependence on stress in crystals with 〈100〉‐orientation in the case of their extension at room temperature has been investigated also. The results obtained are well described by Takeuchi's theory of strain hardening.

Variations in the dislocation density have been observed directly on annealing deformed copper monocrystals in an electron microscope. The process kinetics conforms to a second‐order reaction. The recovery of the dislocation electrical resistance proportional to the mean dislocation density in the crystal was studied in massive monocrystals. Isochronous annealing, as well as annealing under isothermal conditions, were carried out. Two stages were observed on the isochronous annealing curves, one at temperatures below 250 °C, the other in the range from 250 to 450 °C. These two stages correspond to the two substages of the dislocation recovery.

No abstract

No abstract

No abstract