Exploratory study into the effects of an electric field and of high current density electropulsing on the plastic deformation of TiAl

Abstract

The effects of an external electric field (2 kV/cm) and of high density electric current pulsing (2×10 4 A/cm 2, 60 μs duration and 20 pulses per second) on the stress–strain curve of TiAl in compression at 600 °C were determined. The field gave a significant reduction in yield stress followed by a moderate increase in strain hardening. In contrast, electropulsing increased the yield stress and gave a smaller increase in strain hardening. The effects of the electric field and of electropulsing developed during the early stages of plastic deformation ( ε<∼2%) and were retained upon subsequent straining without the field or current. Moreover, initial straining ( ε<∼2%) without an electric field gave a microstructure which did not respond to the electric field applied during subsequent straining. The results suggest that the electric field and the electropulsing had an influence on the microstructure which developed at small strain through an effect on one or more of the following: (a) stacking fault energy, (b) twinning energy or (c) antiphase boundary energy.