Plastic Deformation and Work-Hardening in NaCl

Single crystals of NaCl were compressed at room temperature. The stress-strain curve shows three well-defined stages similar to those found for fcc. metals. The dislocation density, bulk density, and deformation characteristics were studied as functions of stress and strain. The recovery of the dislocation density and bulk density were compared with the recovery behaviour of flow stress and microhardness. During easy glide, slip occurs on a single system and hardening is interpreted in terms of the long-range stress between dislocations. In stage II, slip occurs on additional systems and it is suggested that the hardening is controlled by the forced intersection of dislocations on oblique systems through dislocation debris, in the form of dislocation dipoles, on the primary system.

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