Study on the mechanism of improvement of mechanical properties of Al-Mg-Si aluminum alloys by Cu and Ce

First, the stability and tensile properties of the Al/Mg2Si interface doped with alloying elements in the Al-Mg-Si system of aluminum alloys are calculated from first principles. Then, the two experimental alloys with different components were heat treated and the properties were characterized. Calculations show that when the interface is doped with Cu, the tensile stress that the interface can withstand increases to 3.13 GPa; when the interface is doped with Cu and Ce, the tensile strain that the interface can withstand increases to 20% and the tensile stress that the interface can withstand increases to 4.17 GPa; when the interface is doped with Cu and Sc, the tensile strain that the interface can withstand increases to more than 25% and the tensile stress that the interface can withstand increases to 5.08 GPa or more. Characterization of the organization and properties of the experimental alloys showed that Ce not only increased the peak solid solution temperature of the alloys, but also increased the tensile and yield strengths of the alloys in the extruded state by 16% and 13.74%, respectively. During hot extrusion, Ce was able to promote the precipitation of precipitated phases. During aging, the addition of Ce promoted the aging precipitation of the alloy, which not only increased the number of precipitated phases in the alloy, but also refined the precipitated phases and enhanced the aging strengthening effect of the alloy. This study provides technical guidance for the development of new aluminum alloy materials with high strength and low cost.