Effect of Nd on the microstructure, mechanical properties and corrosion behavior of die-cast Mg-4Al-based alloy

Die-cast Mg-4Al-0.4Mn-xNd (x = 0, 1, 2, 4 and 6 wt.%) magnesium alloys were prepared successfully and influences of Nd on the microstructure, mechanical properties and corrosion behavior of the Mg-4Al-0.4Mn alloy have been investigated. The results showed that with the addition of Nd binary Al₂Nd phase and Al₁₁Nd₃ phase, which mainly aggregated along the grain boundaries, were formed, and the relative ratio of above two phases was in correlation with the Nd content in the alloy. Meanwhile, the grain sizes were greatly reduced with the increasing Nd content. It was found that due to the addition of Nd both the tensile properties and corrosion resistance were improved substantially. The alloy E with 5.96 wt.% Nd content had the best tensile properties and corrosion resistance behavior in our research. While considering the cost of alloy, that with 1.13 wt.% Nd addition has already performed well enough for the improvement of properties. All the analyses demonstrated that the improvement of mechanical properties and corrosion resistance depended on the grain refinement, grain boundary strengthening as well as solid solution strengthening.