Investigation on the Microstructures and Mechanical Properties of RE Containing Mg-5Zn-2Al Alloys

As-cast microstructure Mg-5Zn-2Al-0.3Mn (ZA52) magnesium alloy consists of the α-Mg and eutectic phase Mg51Zn20. The eutectic Mg51Zn20 have been gradually replaced by Al4RE phases when RE is added into the ZA52 alloy, further addition of RE leads to the increasing of grain boundary phases with Mg51Zn20 eutectic compounds reappearing and the grains size refining. Improved elevated temperature properties are obtained as compared to the ZA52 based alloy due to the thermal stability of Al-RE phases. At the temperature up to 175 C, the creep resistance of RE containing alloys decrease with the refining grains size and Mg51Zn20 eutectic compounds increasing.