**4. Conclusion**

**Figure 7.** The perfect wire texture creation during electro-plastic wire dragging in condition of current density **j** and

The thorough analysis shows that the nonthermal current action mechanisms involve electroplastic effect and ponderomotive forces of pulsed current and impact the wire tension decrease sufficiently. More efficient pulsed current action (in comparison with dc) [26, 30], current polarity dependence evidence the nonthermal nature of the occurred processes. In addition, during rapid wire dragging (>10 m/s), the Stewart-Tolman effect takes place (the delay of free electron gas against crystal lattice accelerating in the area of metal deformation inside a drawing ring caused by transition to a smaller diameter). The Stewart-Tolman effect is electronic by nature, and it favors the axial wire texturing to the electro-plastic and its degree of perfection increasing. The typical parameters realized under the electro-plastic effect are

The observed effect is caused by plasticity influence of EPE in metal volume; it relieves the process of axial texture formation and decreases friction in dragging die due to the grain crush

Apart from the perfect grain structure creation for copper, it was observed as follows [26]:

)

wire movement direction **P** vector coexistence [26].

170 Study of Grain Boundary Character

**•** Frequency of current flow (10 kHz)

**•** Current power density (250 kA/cm2

**•** Wire-dragging velocity (rapid dragging) (≥10 m/s)

**•** The number of randomly distributed dislocations decreases.

**•** Current pulse duration (60 μs)

in the near-surface wire areas.

listed below:

The formation of microstructures on metal surface under the interaction of laser radiation of nanosecond durations in regime of near-threshold melting was theoretically and experimentally analyzed. The generations of regular structures in mode of linear gratings or normal and abnormal orientations the periods of which are proportional to laser radiation wavelength were observed. The mechanisms of discussed structure formation are in frameworks of universal polariton model of laser-induced condensed mater damage. In the regime of power density not exceeding the melting threshold, the relief of a new type in mode of quasi-grating of grooves with periods of the order 5 μm and grating orientation orthogonal to the electric field strength vector of laser radiation has been studied. So, the anisotropy of grain growth process was observed. To explain the result of anisotropic growth, the qualitative model was suggested. The model is based on the effect of skin-layer electrons dragged by surface plasmon polaritons. The flux of electrons transfers its momentum to the grain boundary as to the wall given an anisotropic force. So, the produced skin-depth surface layer has properties differing from the bulk of metal.

The considered effect is the surface one. As the volume analog to this effect the well-known electroplasticity, one can be considered. Really, in both cases, the cause of the main effect in metal is the directed flux of electrons.
