WE54 magnesium alloy （Mg-5.4Y-2.3Nd- 1.6 Gd-0.5Zr） exhibits distinct differences in microstructure

micro-area chemical compositions and mechanical properties treated in the different states including as-cast

solid solution （T4） and solid solution-artificial aging （T6）. The microstructure

precipitated phase and micro-area chemical composition of WE54 alloy have been analyzed by means of optical microscope （OM）

X-ray diffraction （XRD）

high-resolution scanning electron microscopy （SEM） and energy disperse spectroscopy （EDS）. The experimental results reveal that in as-cast WE54 alloy

two kinds of new phases Mg

12 Nd and Mg

24 Y

5

with netlike structure are precipitated along the grain boundaries

and the heavy Re element Gd is dissolved into Mg matrix completely

and no precipitated phase containing Gd can be observed in the internal of grains or on the grain boundary. After treated by solid solution

the bulky precipitated phase distributed along the grain boundary in as-cast Mg alloy can be completely dissolved into Mg matrix

which promotes the improvement of the mechanical properties. After treated by solid solution-artificial aging （T6）

a large number of fine rare earth-rich precipitated phase is formed in the alloy. The lamellar precipitated phase is confirmed through analyzing the characteristics of precipitated phase in the sample in cross direction and longitudinal direction. The arrangement of these lamellar precipitated phases extends along three directions with mutual fixed angle of 120°

showing stricter orientation

which leads to the improvement of the strength and the decrease of the elongation of the WE54 alloy.