Microstructure, Mechanical Properties, and in Vitro Corrosion Behavior of Biodegradable Zn-1Fe-xMg Alloy

Zinc (Zn), one of the promising candidates for biodegradable implant materials, has excellent biocompatibility and biodegradability. In this study, as-cast Zn1FexMg (x ≤ 1.5 wt %) alloys were prepared to systematically explore the effects of magnesium (Mg) alloying on their microstructures, mechanical properties, and biodegradability. The microstructure of Zn1FexMg alloy consisted of Zn matrix, Zn + Mg₂Zn₁₁ eutectic structure, and FeZn₁₃ phase. The addition of Mg not only promoted grain refinement of the alloy, but also improved its mechanical properties. The results of immersion tests showed that the addition of Mg accelerated microcell corrosion between different phases, and the modeling of the corrosion mechanism of alloys in simulated body fluid (SBF) solution was discussed to describe the interaction between different phases in the corrosion process. Zn1Fe1Mg possessed superior comprehensive mechanical properties and appropriate corrosion rate, and the values for hardness, tensile strength, yield strength, elongation, and corrosion rate were 105 HB, 157 MPa, 146 MPa, 2.3%, and 0.027 mm/a, respectively, thus revealing that Zn1Fe1Mg is a preferred candidate for biodegradable implant material.