Study on the Microstructure and Properties of Mg-Gd-Y-Nd-Zr Heat resistant magnesium alloy
Abstract
In this assay,on the basis of the Mg-Gd alloy system with creep resistance at high temperature, the light rare earth elements such as Y、Nd and the elemental Zr was added to the alloy to design a new alloy of Mg-10Gd-4Y-2Nd-0.6Zr(wt%). Rolling deformation and solution & aging were adopted to improve the microstructures and mechanical properties of the alloy. The effects of the alloying elements and heat treatment on the microstructures and mechanical properties of the Mg-Gd alloy were examined by XRD, microhardness testing and tensile testing.
The results show that the Mg-10Gd-4Y-2Nd-0.6Zr alloy is composed of a-Mg, Mg12Nd, Mg5Gd, Mg24Gd5, Mg5 (GdY) and Zr. By solutionizing at 500℃/18h +510℃/6h, the strengthening phases such as Mg5Gd, Mg24Gd5, Mg5(Gd,Y) can be dissolveed into the alloy matrix. The microhardness and tensile strength of the alloy are greatly improved after aging at 225℃ for 14h. However, the alloy exhibits the poor plastic deformation ability and thus it can not be used as a deformation alloy.