On the influence of electric currents on plastic deformation

Abstract

Electromagnetic sheet metal forming (EMF) is a high‐speed forming process driven by the dynamics of a coupled electromagneticmechanical system. The purpose of the current work is the investigation of a possible reduction in the yield stress due to electric currents. While thermoelastic and viscoplastic effects are well‐understood, the possible influence of electric currents on dislocation motion, generally referred to as the electro‐plastic effect [3], is still an unresolved issue. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Influence of Alternating Magnetic Field on Physical and Mechanical Properties of Crystals

“…For checking Bilyk's et al model [35,36], it is necessary to separate fast heating from electromagnetic influence.…”

“…Remark: as the authors themselves [36] showed it, characteristic time of thermal diffusion (and correspondingly the time of heating through the surface) is of several orders greater than in case of heating by the current. Therefore, thermal expansion rate will also be smaller.…”

“…Unger et al [36] achieved the conclusion that direct influence of current on dislocations, if it exists, is of second order of smallness compared to the thermal expansion.…”

“…Unger et al [36] prescribe the main part to expansion. They have performed their numerical calculations using two models: thermoselasto-plastic and thermos-elasto-visco-plastic.…”

“…But, the parameter H 0 is the property of the material and depends neither of the size of the sample, nor on the coordinates in the bulk of this sample. If letter 'r' in (36) designates the wire radius, then, (37) with respect to substitution (36) has the meaning of relative stress drop in the circular layer near the conductor's surface. If r is the polar radius that varies from 0 to the radius of the sample, then, j 0 is not a constant and does depend on r.…”