Investigation of electrical-assisted micro-pattern forming process on Zircaloy-4 alloy surface

Electrically-assisted forming is a promising process to improving the plastic forming ability, which has attracted much attention in the fabrication of high-density micro textures. However, few studies have been devoted to quantify the effect of electric current on the micro textures forming process on large-area metal surfaces, especially zirconium alloys. In this paper, the performance of electrically-assisted micro-pattern process on forming high-density micro dimples on the surface of zirconium alloy is investigated. In order to predict the effect of high current density on the forming ability of zirconium alloy, a constitutive model considering current and temperature is developed associated with the results of electrically-assisted tensile tests and constant temperature tensile tests. In order to quantitatively evaluate the effects of current density and temperature on the micro-pattern forming process, the electro-thermo-mechanical coupling finite element model is established through a subroutine that combines the constitutive model with the simulation process. Electrically-assisted micro-pattern forming experiments with various parameters are carried out, and results indicates that the depth of micro dimples fabricated by electrically-assisted micro-pattern forming is greater than traditional micro-pattern forming. The maximum error between the finite element model results and the experimental results is about 10 %, which proves that the established constitutive and finite element model can quantify the electrically-assisted micro-pattern forming process.