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M agnesium alloys have advantages of low density, high specific strength and specific stiffness, good damping, castability, machinability and easy recovery, and are regarded as engineering materials with the greatest potential after aluminum alloys. However, the lower hardness, modulus of elasticity, wear resistance, and high coefficient of thermal expansion of magnesium alloys limit their further application [1-4]. Mg-Zn-Re alloy has attracted more and more attention due to its special structural phase (long-period stacking ordered structures phase, LPSO) and good mechanical properties. A study found that when the volume fraction of LPSO phase in the magnesium matrix reaches 85%-90%, the yield strength of extruded Mg89Zn4Y7 alloy can reach 480 MPa [5]. Onorbe E. [6] prepared Mg100-3xY2xZnx alloys (where x = 0.5, 1 and 1.5at.%) with different LPSO phase contents by the in-situ method, and studied the effects of LPSO phase content on the microstructure and mechanical properties. The results indicate that with the increase of LPSO phase, the room temperature yield strength improved noticeably. LPSO can effectively

Magnesium alloy is a light engineering material, used in aerospace, automotive and electronics industries due to its high damping capacity, good electromagnetic shielding characteristics, high thermal and electrical conductivity, favorable dimensional stability and machinability [1-3]. Unfortunately, the poor corrosion resistance of Mg alloys is still a key factor restricting its wide application. Therefore, it is vital to prepare the Mg alloys with high strength and corrosion resistance. Mg-RE-Zn alloys with long-period stacking ordered (LPSO) phase have received considerable attention owing to their unique microstructures and outstanding mechanical properties. It is proved that LPSO phase can significantly improve the strength, ductility, and creep and corrosion resistance of Mg alloy [1, 4-8]. Cheng et al. [9] revealed that Mg-Zn-Y-Ti alloys with rod-like LPSO phases exhibited a more uniform corrosion mode and better corrosion resistance. Wang et al. [10] reported that Mg 98.5 Y 1 Zn 0.5 alloys containing LPSO phase presented higher corrosion resistance compared with

In this paper, the damping capacities and damping mechanisms of high damping, graphite-reinforced Mg97Zn1Y2 composites were investigated. Composites consisting of different graphite particle sizes (24, 11, and 3 μm) were designed and prepared using the casting method. The microstructure of the composites was examined using optical microscopy (OM) and transmission electron microscopy (TEM), which confirmed that the graphite particles were successfully planted into the Mg97Zn1Y2 matrix. Measurements made with a dynamic mechanical analyzer (DMA) showed that the Grp/Mg97Zn1Y2 composite has a high damping capacity. At the anelastic strain amplitude stage, the damping properties of the Grp/Mg97Zn1Y2 composites were found to be higher than those of the Mg97Zn1Y2 alloy. Furthermore, decreasing the graphite particle size was found to improve the damping properties of the Grp/Mg97Zn1Y2 composites. At the microplastic strain amplitude stage, the damping properties of the Mg97Zn1Y2 alloy were found to be higher than those of the Grp/Mg97Zn1Y2 composites. Moreover, the damping properties of the Grp/Mg97Zn1Y2 composites were found to decrease with increasing graphite particle size. The reason for the increased damping of the Grp/Mg97Zn1Y2 composites during the anelastic strain amplitude stage can be attributed to the increase in the number of damping sources and weak interactions among the dislocation damping mechanisms. At the microplastic strain amplitude stage, the damping properties of the composite are mainly affected by the activation volume of the slipped dislocation.

High-strength Mg-Zn-Y alloy with a long-period stacking ordered (LPSO) phase was chosen as the base alloy, and different Ca were added to it. The phase component and microstructure of the alloys were examined using diffraction of X-rays (XRD) and scanning electron microscopy (SEM). A new phase, Ca 2 Mg 6 Zn 3 , was found to be formed by the addition of Ca. The hydrogen evolution corrosion method and an electrochemical test showed that the amount of hydrogen evolution without Ca addition was twice that with Ca addition. The corrosion resistance of the magnesium alloy improved when the amount of Ca added was. In order to understand the dynamic corrosion process, we soaked Mg 97 Zn 1 Y 2 -X wt-% Ca (X = 0, 0.1, 0.3, 0.6, 1) alloy in 3.5 wt-% NaCl solution for 2, 6, 12 h. It was observed that with an increase in the Ca content, the degree of corrosion of the alloy gradually decreased, and the amount of granular corrosion products covering the alloy's surface also decreased.