Effect of high-density pulsed electric current on the formability of aluminum alloy

In this study, an energy-saving and highly efficient high-density pulsed electric current (HDPEC) method was used to improve the formability of the aluminum alloy A6061 after T6 heat treatment (A6061-T6). An interrupted tensile test was performed, and the HDPEC treatment was applied after tensile deformation. The results showed that the ductility of A6061-T6 improved by approximately 33% after three HDPEC treatments. The Vickers hardness and residual stress were measured to investigate the effect of the pulsed electric current on formability, and they were recovered after HDPEC treatment. Furthermore, the microstructural morphology and dislocation density were investigated to understand the mechanism of formability enhancement. Detailed analysis shows that the formability enhancement of A6061-T6 after HDPEC treatment is mainly attributed to dislocation elimination, while grain size and crystalline orientation changes are side effects. In addition, the results of equivalent heat treatments demonstrate that the athermal effect of the HDPEC treatment plays a crucial role in the removal of dislocations. Thus, due to the contribution of the athermal effect, HDPEC treatment realizes the advantages of low consumption and high efficiency, and can be dedicated to green processing and manufacturing of metallic materials.