Effects of Zr and solid solution treatment on microstructure and mechanical properties of MgEr-Zn alloys were investigated by OM（optical microscopy）

SEM（scanning electron microscopy）

EDS（energy dispersed spectrometer）

XRD（X-ray diffraction）and compressive testing.The results reveal that the phase structure change is absent with Zr addition

however

the percentage composition of X phase in grain boundary is decreased.The microstructure and mechanical properties of Mg97.5Er2Zn0.5alloy are improved significantly with Zr addition.Meanwhile

the solution time of X phase is reduced.The LPSO phase can be observed in the furnace cooled alloys after solid solution treatment

while it is absent in the water cooled alloy.After solid solution treatment

the mechanical properties of the solution-treated alloys are higher than those of the as-cast alloys

and the Mg97.32Er2Zn0.5Zr0.18 alloy is the higher than Mg97.5Er2Zn0.5alloys in mechanical properties.In addition

the mechanical properties of furnace cooled alloys are higher than those of the water cooled alloys.