Constitutive Model and Microstructural Evolution for Tensile Behavior of Carbon Steel Ultrathin Strip under Pulsed Electric Field

08AL carbon steel ultrathin strip has a wide application prospect in the field of the microelectromechanical system. However, the application of the material is limited by the plastic deformation capacity because of the decrease in thickness. In this paper, a pulsed electric field was integrated into tensile tests to investigate the influence of the electroplastic effect on the deformability and microstructural evolution of the 08AL carbon steel ultrathin strip. Based on the experimental results, a modified Johnson-Cook constitutive model was developed to quantify the Joule thermal and non-thermal effects on the flow stress of the material. A finite element model of the electric field-assisted tensile test based on the custom material hardening subroutine VUMAT was developed to analyze the stress and strain characteristics under different forming parameters and locate the position of the microstructural characterization of the specimens. The experimental results showed that the tensile strength at a current density of 1.50 A/mm2 decreased by 16.5% compared to the result at room temperature, while the elongation increased by 32.1%. In addition, the result of microstructural characterization revealed that the grains were refined, and the dislocations slipped within the grains and at grain boundaries under the average current density of 1.50 A/mm2. Therefore, the forming method assisted by the pulsed electric field for the 08AL carbon steel ultrathin strip is expected to significantly enhance its forming limits and broaden its application areas. © 2024 Chinese Mechanical Engineering Society. All rights reserved.