Investigations of the properties of Mg–5Al–0.3Mn–xCe (x = 0–3, wt.%) alloys

Mg–5Al–0.3Mn–xCe (x = 0–3, wt.%) alloys were prepared by metal mould casting method. The microstructures and mechanical properties were investigated. The results revealed that the main phases of as-cast Mg–5Al–0.3Mn alloy consist of α-Mg matrix and β-Mg17Al12 phase. With the addition of Ce element, Al11Ce3 precipitates were formed and mainly aggregated along the grain boundaries. The amount of the Al11Ce3 precipitates increased with increasing addition of Ce, but the amount of β-Mg17Al12 phase decreased. The highest tensile strength was obtained in Mg–5Al–0.3Mn–1.5Ce alloy. The ultimate tensile strength (UTS), yield strength (YS) and elongation at room temperature are 203 MPa, 88 MPa and 20%, separately. Hot rolling was performed on Mg–5Al–0.3Mn–1.5Ce alloy. Microstructure and mechanical properties of the hot-rolled alloy were also studied. The results showed that after hot rolling, grain size was greatly refined to about 15 μm. The UTS and YS were obviously improved to 318 MPa and 225 MPa, respectively, which were 57% and 156% higher than those of the as-cast alloy. But the elongation was decreased to 9%.