Effects of Gd addition on as-cast microstructure, tensile and creep properties of Mg-3.8 Zn-2.2Ca (wt%) magnesium alloy

In this paper, the as-cast microstructures, tensile and creep properties of Mg-3.8Zn-2.2Ca-xGd (x=0, 0.36, 0.88, 1.49 and 2.52 wt%) magnesium alloys are investigated and compared. The results indicate that the additions of 0.36-2.52 wt%Gd to the Mg-3.8Zn-2.2Ca ternary alloy can refine the grains of the alloy, and an increase in Gd content from 0.36 wt% to 2.52 wt% causes the grain size to gradually decrease. Furthermore, the additions of 0.36-2.52 wt%Gd to the Mg-3.8Zn-2.2Ca ternary alloy can also improve the tensile properties of the alloy, and the alloy with the addition of 1.49 wt%Gd exhibits the best tensile properties. In addition, the additions of 0.36-2.52 wt%Gd to the Mg-3.8Zn-2.2Ca ternary alloy do not change the creep mechanism of the alloy. However, the creep properties of the Gd-containing alloys are improved, and an increase in Gd content from 0.36 wt% to 2.52 wt% causes the creep properties to gradually increase. Amongst the Gd-containing alloys with the additions of 0.36 wt%, 0.88 wt%, 1.49 wt% and 2.52 wt%Gd, the alloy with the addition of 1.49 wt%Gd exhibits the relatively optimal tensile and creep properties. (C) 2013 Elsevier B.V. All rights reserved.