The mechanical and corrosion resistance of Mg-Zn-Ca-Ag alloys: the influence of Ag content

Abstract

Biomedical magnesium alloys have become an ideal material for degradable implants because of their similar density and elastic modulus with human bone. In this study, Mg-3Zn-0.2Ca-xAg (x = 0%, 0.1%, 0.3%, 0.5%, 0.7%, wt.%) alloys were fabricated to enhance the comprehensive properties of the Mg-3Zn-0.2Ca (wt.%) alloys. The microstructure shows that the alloy possesses relatively smaller grain size of 2.08 μm when the addition of Ag is 0.3 wt.%. The Mg-3Zn-0.2Ca-0.3Ag also owns the best mechanical properties whose elongation, yield strength and tensile strength are 4.57%, 5.7%, and 2.4%, respectively, higher than that of Mg-3Zn-0.2Ca. The electrochemical experiments shows that Mg-3Zn-0.2Ca-0.3Ag has lower corrosion current density (30.5 μA/cm2), which indicates that its corrosion resistance has been improved. After immersed in simulated body fluids at 37 ℃ for 15 days, the hydrogen release rate and degradation rate of the Mg-3Zn-0.2Ca-0.3Ag is significantly lower than that of Mg-3Zn-0.2Ca. In addition, the cytotoxicity test with L 929 cells shows that Mg-3Zn-0.2Ca-0.3Ag alloy has good biocompatibility.

Keywords

• Ag
• Microstructure
• Mechanical properties
• In vitro corrosion