Effect of athermal effect reconfiguration of electroplasticity on strengthening in 1060-H24 pure aluminum under low-density pulse current

The temperature response, mechanical properties and microstructural evolution of 1060-H24 pure aluminum sheet under different current densities and loading directions were systematically studied by using electric pulse-assisted tensile test and characterization techniques including electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM), and the athermal effect mechanism of strength–plasticity improvement was revealed. The findings demonstrate that following the application of electric pulse treatment at a current density of 5 A/mm 2 , the yield strengths and fracture strains in the 0°, 45° and 90° directions are increased by 0.33%–3.34% and 2.62%–14.84%, respectively. Under the condition that the Joule temperature rise (≤2.4 °C) caused by this current density is negligible, pulse current changes the intensities of Copper, Brass and S textures and causes the decrease of the geometrically necessary dislocations (GNDs) density and fraction of low-angle grain boundaries, which confirms the athermal effect. The slight strength increase stems from the competition between reduced dislocation strengthening due to GNDs decrease and enhanced strength through transformation of high-energy dislocation tangles into low-energy dislocation networks that optimize the hard-oriented {111}//RD texture. The improved fracture strain is attributed to current-induced uniform dislocation distribution and dislocation disentanglement-reorganization into nets.