Effect of rare earth elements on the microstructure and properties of a die-cast aluminum alloy

The effects of the rare earth elements Ce, La and Sm on the microstructure and mechanical properties of a die-cast aluminum alloy were studied. First, the optimal percentage content of the main elements in the alloy was determined by a single factor and by orthogonal experiments based on the composition range of ADC12 aluminum alloy. The results showed that the optimal percentage content of the main elements in ADC12 die-cast aluminum alloy were 11 wt.-% Si, 2.5 wt.-% Cu, 0.5 wt.-% Mn and 0.3 wt.-% Mg. The tensile strength was 285 MPa and the fracture strain 2.23%. Then, three rare earth elements of varied contents were added to the above-mentioned aluminum alloy. The tensile strength and elongation of the alloy were increased through the addition of rare earth elements. The comprehensive mechanical property of the alloy was best when Ce, La and Sm levels were at 0.6, 0.4 and 0.2 wt.-%, respectively, in the single factor test. Sm had the largest influence on the comprehensive mechanical properties of the alloy, followed by Ce and La which had the least influence.