High-Performance Mg-4AI-4RE (RE = Cerium and Lanthanum) Die-Casting Alloy

This paper presents an overview of the recent development of die-cast Mg-4Al-4-RE (AE44, where RE is a mixture of Cerium and Lanthanum) to highlight some of its characteristics which differ from other magnesium alloys. Die-cast AE44 exhibits a distinct hardening response upon ageing (T5) due to the precipitation of nanoscale Al-Mn particles. The T5 ageing leads to a significant improvement in strength without reducing the ductility in AE44. Hence, T5-aged AE44 has a better strength-ductility combination than other magnesium die-casting alloys. AE44 also exhibits high strain-rate sensitivity, which manifests as an increase in work hardening with increasing strain rate. The amount of anelasticity in AE44 is also quantified and some significant anelasticity is observed at low stress-strain levels. A higher offset strain method is proposed to improve the accuracy of yield strength measurement for die-cast magnesium alloys. It is shown that the properties of AE44 exceed many aluminium casting alloys.