Effect of Ce addition on castability, mechanical properties and electric conductivity of Al-0.3Si-0.2Mg alloy

Effect of rare earth (RE) element cerium on castability, mechanical properties and electric conductivity of Al-0.3Si-0.2Mg alloy was investigated. With Ce addition, the fluidity of Al-0.3Si-0.2Mg alloys is increased and the hot tear sensitivity (HTS) is decreased remarkably, and the optimum Ce addition level is about 0.2%. Significant improvement of castability (especially the HTS) is attributed to the remarkable grain refinement from Ce addition. Ce addition also leads to a remarkable rise in electric conductivity, mainly due to the reduction of Fe and Si solutes in alpha-Al solution. T7 heat treatment further improves the electric conductivity. However, in the case of T7 condition, Ce-induced improvement of conductivity is not considerable. An excellent combination of castability, strength and conductivity can be obtained with 0.3% Ce addition in the studied alloy.