Effects of alloying elements (Ca and Sr) on microstructure, mechanical property and in vitro corrosion behavior of biodegradable Zn-1.5Mg alloy

Zn, a promising biodegradable material, possesses excellent biocompatibility and biodegradability, however its low strength and hardness largely limit its application in biodegradable implants. The addition of alloying elements would generally be suggested as an effective method for improving the mechanical properties. In the current study, alloying with a minor amount of Ca or Sr in Zn-1.5Mg alloy, the ternary alloys were composed of the matrix Zn and precipitated phase (Mg2Zn11 and CaZn13 for Zn-1.5Mg-0.1Ca alloy, Mg2Zn11 and SrZn13 for Zn-1.5Mg-0.1Sr alloy, respectively). Besides, the grain size of ternary alloys became more homogeneous and smaller than that of Zn-1.5Mg alloy. Meanwhile, the effect of alloying elements on the mechanical properties and corrosion behavior of Zn-1.5Mg alloy were analyzed. The results showed that the ternary alloys exhibited much higher yield strength (YS), ultimate tensile strength (UTS) and elongation than those of Zn-1.5Mg alloy. The measured corrosion rates of the ternary alloys were slightly increased due to galvanic corrosion reaction. Besides, a model of the corrosion mechanism in the simulated body fluid was discussed here based on the results of the studied alloys.