The electroplastic effect in coarse-grained and ultrafine-grained titanium

Abstract

One of the well-known features of the external action of the electric current in the process of plastic deformation is the electroplastic effect manifesting in a decrease in flow stresses and an increase in plasticity (deformability). Understanding the nature of the electroplastic effect provides targeted regulation and application of the effect to improve the efficiency of metal working processes or to change the structure and properties of materials. The deformation behavior of commercially pure titanium under the impact of an electric current of critical density from 12 to 400 A/mm2 is considered. The electroplastic effect in coarse-grained (d = 50 μm) and ultrafine-grained (d = 500 nm) VT1-0 titanium has been studied under a combination of tensile deformation and applied current of various modes and regimes, including the single-pulse, multipulse and direct current modes. It is shown that a decrease in the grain size contributes not only to an increase in the strength characteristics, but also to a decrease in the electroplastic effect, the mechanism of which is closely related to the density of mobile dislocations. It has been shown that the manifestation of the electroplastic effect in titanium is controlled by the grain size, and a decrease in the grain size leads to its electroplastic degradation and finally to the complete disappearance in the amorphous state due to a decrease in the density of free dislocations.