Effect of Er contents on the microstructure of long period stacking ordered phase and the corresponding mechanical properties in Mg-Dy-Er-Zn alloys

The influence of Er contents on the mechanical properties and microstructure of the long period stacking ordered (LPSO) phases in Mg96.6Zn0.91Dy2.17Er0.32 and Mg96.23Zn0.88Dy2.21Er0.68 alloys have been studied. The results showed that the LPSO structures in the two alloys are 18R-type in the as-cast state. And co-existence of 18R-type and 14H-type LPSO phases after heat-treated has been observed in the two alloys. After hot extrusion, the ultimate tensile strength (UTS), yield strength (YS) and elongation (EL) of the Mg96.6Zn0.91Dy2.17Er0.32 alloy have reached the value of 303.42 MPa, 172.76 MPa and 18.31%, respectively. The UTS, YS and EL of the as-extruded Mg96.23Zn0.88Dy2.21Er0.68 alloy are 334.63 MPa, 214.85 MPa and 19.59%, respectively.