Effects of direct current on the microstructures and properties of 7B04 aluminum alloy during solid solution and artificial ageing

Abstract:

The microstructures and mechanical properties of 7B04 aluminum alloy solid solution at 470oC and aged at 100-140 oC without and with electric current were investigated by tensile test, scanning electron microscope (SEM) and transmission electron microscope (TEM). Compared with the traditional T6 treatment (470 oC/30min+120 oC/24h), applying electric current of 500A during solid solution and/or ageing treatment can increase both the tensile strengths and elongation at the age-peak state, due to the significant increase of the precipitation density of Guinier- Preston II (GPII) zones. Applying electric current during solid solution can significantly reduce the time to the peak strength by 12h in the subsequent ageing alloy