Enhancement of the ductility of polycrystalline NaCl by an electric field

The influence of an electric field E ≈ 1kV/cm on the plastic deformation in tension of polycrystalline (d0 = 30μm) 99.9% NaCl was determined at 532°C (0.75Tm) using two electrode configurations. The following is a summary of the results and the conclusion derived therefrom: 1. The field produced a decrease in the flow stress and an appreciable increase in the ductility. 2. The magnitude of the stress exponent n from strain rate cycling tests was 9.5, independent of strain and electric field. This suggests that the rate-controlling mechanism did not change with the field. 3. Dynamic grain growth occurred during the tests without a field; grain refinement (dynamic recrystallization) occurred with the field. 4. Turning the field "on" and "off" during the course of a test gave an increase in strain hardening when the field was turned "on" and a decrease when it was turned "off". The difference decreased with strain. 5. The results suggest that the field led to the development of a dislocation structure which was conductive to the nucleation of new grains. Moreover, the field retarded the growth of the new grains[10].