Influence of an electric field on the plastic deformation of polycrystalline NaCl at elevated temperatures

Abstract

The effect of a d.c. electric field of 1 kV/cm on the plastic deformation of polycrystalline 99.9% NaCl was determined in compression at 23–532°C (0.28–0.75 T M) and strain rate ε=8.3×10 −4 s −1. Upon removing the effect of Joule heating it was found that the reduction in the flow stress produced by the field increased with temperature from 0.28 to 0.4 T M, reached a maximum at 0.4 T M and then decreased, becoming nil at 0.75 T M. It is proposed that the reduction in flow stress resulted from an enhancement of cross-slip due to an increase in stacking fault energy. The field had no detectable effect on the plastic deformation kinetics at constant structure in the temperature range 0.28–0.6 T M (cutting of forest dislocations), nor did it appear to have a significant influence on dislocation glide and climb at 0.75 T M.