Effect of pulsed electric field on the microstructure and mechanical properties of a recycled ADC12 aluminum alloy

The effect of current density on the microstructure and mechanical properties of cast ADC12 recycled aluminum has here been investigated by using a pulsed electric field and a self-developed high-power pulsed device. The results showed that the pulsed electric field could refine the microstructure of cast ADC12 recycled aluminum alloy and enhance its frictional properties. As a result of the pulsed electric field treatment, the eutectic Si phase changed from long rod-like (or platelet-like) to short rod-like (or fiber-like) and was aggregated and distributed around the a-Al phase. Also, the long needle-like beta-Fe phase changed to short needle-like, and the number of round spherical beta-Fe phases decreased and changed to small-sized spherical. For a current density of 13.636 A/mm(2), the average area of the a-Al phase decreased by 10% (as compared with the original sample). Also, the average area of the eutectic Si phase and beta-Fe phase decreased by 8% and 86%, respectively. In addition, the average length decreased by 36%, and the refinement effect was the best. Furthermore, the deep etching analysis showed that the three-dimensional morphology of each phase was significantly refined. The current density was 13.636 A/mm(2) and the friction coefficient decreased by 17.8%, as compared with the original sample. Also, the Rockwell hardness and yield strength became significantly increased. In addition, there was an obvious wear surface refinement, the alloy wear surface became smoother, the area of spalling pits was smaller, and the furrow parallel to the friction direction was both shallower and smaller. The size of the plastic shear lip, as accumulated on both sides of the furrow, was smaller, and the wear degree of the alloy surface was greatly reduced.