Manufacturing aspects relating to the effects of direct current on the tensile properties of metals

For metals, deformation is commonly conducted at elevated temperatures, reducing the overall process energy and cost. However elevating the temperature has many drawbacks, including high tool/die adhesions, environmental reactivity, etc. Therefore, this study examines using an electrical current to reduce the deformation energy and presents electricity's effects on the tensile properties of various materials. The influences of strain rate and cold work are also investigated. The results demonstrate that, when current flows through a metallic specimen, the material yield strength, flow stress, and elastic modulus are decreased; strain weakening occurs; and the total energy of deformation is decreased. These changes in the engineering stress-strain behavior occurred in all of the materials tested and are much greater than can be accounted for by resistive heating. However the effects diminish with increasing strain rate. The analysis shows that applying electricity during deformation provides a viable alternative to increasing the workpiece temperature for deformation-based manufacturing processes.