Abstract
In connection with observations of the creep bahaviour of single crystals of NaCl, a systematic investigation of the creep substructure was conducted by means of the etch-pit technique. A typical substructure consists of tilt walls along {110} planes surrounding parallelipipedic blocks. The evolution of the substructure with temperature, stress and time is described and a model for its formation is porposed. The experiments lead to the conclusion that the size of the blocks has no influence on the creep rate but that the cell walls are effective sites for blocking and annihilation by climb of dislocations.