Effect of Pulse Current on Friction Coefficient of 7075-T6 Aluminum Alloy and Microstructure Analysis

Abstract

A study on friction is necessary to improve the forming quality of stamped parts. It has been found that pulsed current can improve the forming properties of aluminum alloys, mainly in terms of Joule heat and electroplasticity. Thus, this article revolves around the effect of different current densities on the friction and wear of 7075-T6 aluminum alloy sheets. The change rule of friction coefficient under different current densities is derived through a friction test, and the variable friction simulation model is established. Scanning electron microscope (SEM) and X-ray diffraction (XRD) are used to analyze the micromorphology and elemental composition of the wear surface. The diffraction peaks of Al are analyzed by XRD, and grain size and dislocation density are calculated. Finally, the actual stamping results are compared with the simulation results. The results show that the friction coefficient decreases with the increase of current density when the current density is less than 10 A/mm2, and the wear mechanism is mainly abrasive wear. When the current density is greater than 10 A/mm2, the friction coefficient increases with the increase of current density and the wear mechanism is mainly adhesive and electrical wear. The grain size and dislocation density mainly depend on the electrical plasticity. The variable friction model's simulated thickness distribution and rebound results align more with the situation.