Effects of RE on the microstructure and mechanical properties of Mg-8Zn-4Al magnesium alloy

Effects of rare earth (RE) alloy element on the microstructure and mechanical properties of M-8Zn-4Al (ZA84) alloy have been investigated. The differential scanning calorimetry (DSC) technique was used to study the solidification and aging process of ZA84 and ZA84-xRE alloys. The results show that a new quaternary precipitate Mg3Al4Zn2RE forms during the solidification and its phase transformation temperature point is 413 degrees C in RE-containing ZA84 alloys. The microstructure of ZA84 alloy can be refined, epsilon phases formed, microhardness of the matrix increased and time for attaining microhardness peak value of aging ZA84-xRE alloys delayed, with increasing RE. Thus, the room temperature and high temperature tensile properties of as-cast and aged ZA84 alloys can be improved by RE addition. (c) 2005 Elsevier B.V. All rights reserved.