| Magnesium alloys with high strength and stiffness, damping properties and machinability such advantage as a result of being a focus in the field of material science. However, the development and application has been restricted because of its oxidation easy, poor corrosion resistance, low high-temperature strength and creep resistance. Rare-earth metal is considered to be one of the most effective and valuable elements in the field of improving the high-temperature mechanical properties and corrosion resistance of Magnesium alloys. Therefore, the development of rare earth metal used in magnesium alloys has become the majority of workers interested in the subject.In all the rare earth elements, Y is considered to be most effective elements to improve high-temperature properties of magnesium alloys, and the Nd can be made of magnesium alloys in high temperature and room temperature the same time intensify. This article based on the study of high-performance Mg-Y-Nd alloys. Systematic study has been done of microstructure, room temperature and high temperature mechanical properties of cast and aging Mg-Y-Nd alloys, and dry sliding friction and wear properties and corrosion of aging Mg-Y-Nd alloys. The most widely used alloys AZ91 are selected as a contrast in performance tests. Come to the following conclusions:⒈Rare earth elements Y, Nd can refine grain. In the solidification process, Y and Nd atoms are concentrated in the crystalα-Mg surface, and will prevent grain from further growing . In the cast Mg-Y-Nd alloy, new phases made up of Mg24Y5 and Mg12Nd precipitate into reticular in grain boundary. And there is a small precipitation within crystal. After solution and aging treatment, there are large granular new phase Mg24Y5 and Mg12Nd2Y precipitated within crystal. Thermodynamic analysis found that the new phase has a higher melting point.⒉Cast and aging Mg-Y-Nd alloys have excellent mechanical properties both at room temperature and high temperature. The ultimate tensile strength and elongation of cast and aging Mg-Y-Nd alloys at room temperature and high temperature of 200°C is higher than AZ91 alloy at room temperature and 150°C. The aging Mg-Y-Nd alloys have higher strength and better plasticity than cast alloys at the same experimental conditions.⒊The fracture surface of cast and aging Mg-Y-Nd alloys is mixed with cleavage fracture and toughness fracture at room temperature. And the fracture mode changes to the toughness fracture with the rising temperature.⒋In experimental conditions, aging Mg-Y-Nd alloys and AZ91 alloys both have occurred changes from minor wear (mainly oxidation wear, abrasive wear and minor delamination wear) to serious wear (mainly serious delamination wear and fusion wear). Rare earth elements Y, Nd increase stability of oxide film covered on the wear surface, and improve the carrying capacity of Magnesium alloys. All of those delayed changes from minor wear to serious wear effectively. This also proves aging Mg-Y-Nd alloys have superior wear-resistance to AZ91 alloys.⒌Under the same corrosion conditions, aging Mg-Y-Nd alloys have superior corrosion-resistance to AZ91 alloys. On one hand, the corrosion resistance ofα-Mg solid solution with Al is far poor thanα-Mg solid solution with rare earth elements Y, Nd. On the other hand, rare earth phases dispersed within grains prevent corrosion from developing deeply.
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