Effect of modification treatment on the microstructure and mechanical properties of Al–0.35%Mg–7.0%Si cast alloy

The effects of barium modifier content on the mechanical properties, microstructures, and wear resistance of Al–Mg–Si alloys at room temperature have been analyzed. The modification caused the disappearance of primary silicon with the formation of solid solution dendrites and fine fiber or rod-like eutectic silicon instead of plate-like structures. This resulted in a highly branched filamentary form with a better distribution of Si particles. The Ba modifier with 1.0 wt.% exhibited the best results for the mechanical properties of alloy. The Al–Mg–Si alloy with modification had good remelting property. The effect of modification was still obvious after being remelted for four times. The scanning electron microscope fractographs of tensile samples at different magnifications revealed that the alloys failed in a mixed-mode fracture comprising of intergranular fracture, quasi-cleavage plane, and transgranular shear.