FORMATION OF DOUBLE TWIST BOUNDARIES DURING PLASTIC DEFORMATION OF COPPER SINGLE CRYSTALS.

The formation is due to the presence of piled-up screw dislocations of the opposite sign. The fact that the rate at which dislocations of one sign build up in sub-block boundaries does, and the work-hardening factor does not, depend on deformation temperature shows that double boundaries cannot be completely responsible for work-hardening.