Structure stability and mechanical properties of high-pressure die-cast Mg-Al-Ce-Y-based alloy

With the aim to further improve the mechanical properties of Mg-Al-RE-based alloy, Mg-3.0Al-1.8Ce-0.3Y-0.2Mn alloy was prepared by high-pressure die-casting technique. The microstructure, thermal stability of intermetallic phases and mechanical properties were investigated. The results show that the alloy is composed of fine primary α-Mg dendrites and eutectic in the interdendritic regions. The intermetallic phases in eutectic are Al ₁₁(Ce,Y) ₃ and Al ₂(Ce,Y) with the former being the dominant one. The thermal stability of Al ₁₁(Ce,Y) ₃ is conditioned. It is basically stable at temperature up to 200 °C within 800 h, while most of the Al ₁₁(Ce,Y) ₃ intermetallics transform to Al ₂(Ce,Y) at higher temperature of 450 °C for 800 h. The alloy exhibits remarkably improved strength both at room temperature and 200 °C, which is mainly attributed to the reinforcement of dendrite boundaries with Al ₁₁(Ce,Y) ₃ intermetallics, small dendritic arm spacing effect as well as the solid solution strengthening with Y element.