Microstructure and Properties of Experimental Mg-9Al-5RE-1Zn-Mn Magnesium Alloy

In this paper, an experimental Mg-Al-RE-type magnesium alloy, named AEZ951, is presented. The chemical composition of the investigated alloy was ca. 9 wt% Al, 5 wt% RE (rare earth elements), 0.7 wt% Zn and 3 wt% Mn. The experimental material was gravity cast into a cold steel mould. Microstructure analyses were carried out by light microscopy, along with X-ray phase analysis and scanning electron microscopy with an energy-dispersive X-ray spectrometer (SEM + EDX). Detailed investigations disclosed the presence of primary dendrites of an  (Mg) solid solution and Al 11 RE 3 ,  and Al 10 RE 2 Mn 7 intermetallic compounds in the alloy microstructure. The volume fraction of the Al 11 RE 3 phase and  +  eutectic was also presented. The hardness, impact strength, tensile strength as well as the yield strength of the alloy were examined in tests at room temperature. The examined experimental Mg-Al-RE-type magnesium alloy exhibited higher mechanical properties than the commercial AZ91 alloy (cast in the same conditions).