Microstructures And Properties Of Mg-0.5zr-1.8zn-Xgd Bio-Magnesium Alloys

The effects of Gd content on the microstructure, mechanical properties and corrosion resistance of as-cast Mg-0.5Zr-1.8Zn-xGd bio-magnesium alloy were studied at high melting temperature (780 +/- 5 degrees C). The results show that the grain size of the alloy decreases with the increase of Gd content within the range of 0%similar to 2.5% (mass fraction). The alloy without Gd is mainly composed of alpha-Mg and a small amount of dispersed micron Zr particles, while the alloy containing Gd is mainly composed of alpha-Mg and (Mg, Zn)(3)Gd phase of different morphologies. The mechanical properties of the alloy are improved at first and then reduced with the increase of Gd content. When the Gd content is 1.5%, the alloy has better mechanical properties than others. Besides, the corrosion resistance is also improved at first and then reduced with the increase of Gd content. The alloy with 1.5% Gd content possesses a better corrosion resistance than others because of the uniformly distributed and fine reticulated second phase. In the immersion test of 120 h, the static corrosion rate of the alloy with 1.5% Gd content is 0.801 +/- 0.04 mm/a, and the corrosion morphology is relatively uniform.