Microstructural stability and creep properties of die casting Mg-4Al-4RE magnesium alloy

The AE44 (Mg-4Al-4RE) alloy was prepared by a hot-chamber die casting method. The microstructure, microstructural stability and creep properties at 175 °C were investigated. The microstructure was analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and the Rietveld method. The results show that die cast AE44 magnesium alloy consists of α-Mg, Al11RE3, Al2RE and Al2.12RE0.88 phases. The Al11RE3 phase is thermally stable at 175 °C whereas the metastable Al2.12RE0.88 phase undergoes a transition into the equilibrium Al2RE phase. The alloy investigated is characterized by good creep properties at temperatures of 175 °C and 200 °C.