Microstructure and Corrosion Resistance of Low Gd Magnesium Alloys

The phase composition and microstructure of Mg-6Gd-2Y-1Sb-0.5Zr and Mg-9Gd-2Y-1Sb-0.5Zr (%) alloys were studied by optical microscopy (OM),scanning electron microscopy (SEM) and X-ray diffraction (XRD),and the corrosion resistant properties of the alloys were tested by corrosion weightlessness experiment.The results showed that the microstructure of the alloys was mainly composed of dendritic eutectic phase along the grain boundary distribution and a small amount of granular phase composition in the grains,and the alloy′s precipitated phase included α-Mg phase,Mg5Gd phase and Mg24Y5 phase.The corrosion degree of the alloys was increased with increasing the concentration of the NaCl,and the corrosion product was mainly Mg(OH)2,the alloys had low corrosion rates and prefect corrosion resistant performance．