On the additivity of acoustoplastic and electroplastic effects

The influence of high density current pulses (approximately 10³ A mm⁻² for 25–80 μs) and the ultrasonic deformation (2 × 10⁴ Hz) on the flow stress of Cu tested in uniaxial tension at 300 K were investigated with the objective of determining the mechanisms of the joint action of electroplastic (EPE) and acoustoplastic (APE) effects. The experimental procedure used allows synchronization of the current pulse and the ultrasonic deformation and allows the current pulse and the ultrasonic deformation to be shifted in phase. It was found that the combined APE + EPE is smaller than the sum of separate effects and depends on the phase shift between the current pulse and the ultrasonic deformation. An extremum of the combined APE + EPE at a certain phase shift between the current pulse and the ultrasonic deformation was detected. An increase in the EPE after prior action of ultrasonic deformation was detected. Employing the thermally activated plastic flow concept, a differential equation for combined APE + EPE is proposed.