Electroplastic effect under the simultaneous superposition of electric and magnetic fields

In recent years a number of models were proposed in which the electroplastic effect in the process of thermal fluctuation motion and generation of dislocations was considered to be a result of lowering potential barriers by the electromagnetic field. The experiments carried out so far reveal the surface character of the electroplastic deformation. To test the effect, the free surface has been perturbed by an electromagnetic field. The deformation of a bismuth crystal in response to application of mechanical stress and concurrent constant magnetic field and an impulse electric current has been studied. To illustrate the deformation process in single crystals of bismuth under the simultaneous effect of the electric and magnetic fields, a special device was designed as a supplement to the standard microhardness measuring equipment. There are two factors that increase plasticity in the case of the concurrent application of magnetic and electric fields. The first one is the damped elastic sonic vibrations caused by the Ampere force. In the case of deformation by twinning, these vibrations result in an increase of wedge-shaped twin around the imprint of the diamond indentor. The second factor is the electric charge on the free surface. The electric charge on the cleavage face increases the run of the twinning dislocations. (C) 1999 American Institute of Physics. [S0021-8979(99)07617-3].