Microstructure and Mechanical Properties of Mg-3Al-1Zn-xRE Alloys

In this work, the influence of element RE on the microstructures and mechanical properties of the hot extuded Mg-3Al-1Zn-xRE alloys (with element RE content of 0.05, 0.1 and 0.2 wt pct) has been investigated and compared. It was found that RE can bring about precipitations phase that is identified as Al11RE3 by X-ray diffraction and transmission electron microscopy (TEM). The grain sizes would not be refined after adding RE element. Al11RE3 phase would increase strength and decrease the ductility. The addition of RE element affects dynamic recrystallized process and even reorientation of recrystallized grains. The results showed that the mechanical properties of AZ31+RE alloy are affected by combination of Al atoms, Mn atoms, Al11RE3 phase and grains orientation. It is important to consider the ratio of RE/Al when designing new Mg-Al-RE alloys.