Measurement of the electroplastic effect in Nb

The procedures employed to measure the electroplastic effect resulting from the application of a high-density ( approximately 105 A cm-2) electric current pulse of 120 mu s duration during the plastic deformation of Nb in a uniaxial tension test are described in detail. Special attention is focused on eliminating the side effects of the current, such as result from Joule heating and the pinch effect. Thermally activated plastic-flow theory is employed to calculate the side contributions of thermal softening and load oscillations resulting from inertia effects. The electron-dislocation interaction contribution is derived for Nb and found to be about four times that for the FCC metals Al and Cu, and to increase with an increase in the plastic deformation rate just before the application of the current pulse.