Part Of The Rare Earth Magnesium Alloy System Study On The Relationship Between The 400 ℃

Due to its excellent performance, magnesium-based alloys have been widely used as lightweight structural materials in many fields, such as automobile,3C products, aerospace and so on, and consequently become a hot research field of structural materials in recent years. In the research of castable heat-resistant magnesium alloys, rare-earth elements are selected as effective alloying elements due to the formation of high stability intermetallic compounds. In this paper, within the work of Key Project of "The phase diagrams and alloying principle of high performance magnesium structural materials (No.50731002)" which is financially supported by National Natural Science Foundation, equilibrated alloys of important composition were prepared and determined by using scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD) analysis and the following results have been carried out.(1) Phase equilibrium in Mg-rich corner of Mg-Ca-Nd ternary system at400℃was critically investigated, and the eutectic reaction temperature of three-phase region of α-Mg+Mg2Ca+Mg41Nd5was determined by using heat flux differential scanning calorimeter (DSC), reliable experimental data will be provided for the construction of thermodynamic database of Mg-Ca-Nd ternary system.(2) Phase equilibrium in Mg-rich corner of Mg-Ca-Gd ternary system at400℃was critically investigated, a ternary compound with identical crystal structure of Mg41Ce5was discovered in this ternary system, while Mg41Gd5is unstable in Mg-Gd binary system, the eutectic reaction temperature of the similar three-phase region was determined by using DSC as in Mg-Ca-Nd ternary system, reliable experimental data will be provided for the construction of thermodynamic database of Mg-Ca-Gd ternary system. (3) Phase equilibrium in Mg-rich corner of Mg-Ce-Gd system at400℃was investigated, a three-phase region of α-Mg+Mg41Ce5+Mg12Ce was determined, it has been found that Gd can not be dissolved into Mg12Ce, and there is a composition region in Mg3Ce single-phase field.